Plans for near future of E@H ?


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astro-marwil
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Message 119870 - Posted 1 Nov 2012 11:24:38 UTC

    Hallo!
    FGRP1 is out of data and S6LV1 will end close to the end of this year.
    So I had a look into LSC-Virgo data analysis white paper - many thanks to joe areeda for posting this((:-))) -. But the only I found directly related to E@H was on page 131, in chaper 7 "LSC Computing and Software" the last block: "The LSC also developed the Einstein@Home project to leverage an alternative distributed computing paradigm for its most formidable computing challenge, the search for gravitational waves from isolated pulsars. The pulsar analysis puts reduced demand on quick turn-around and has low data flow, but requires PFlops of computing power. The ....". (We just reached 0.7PFLOPs.)
    On A@H are no following up projects for test now.
    For fresh data form the Advanced LIGO detectors we will have to wait for another year at minimum, according to the official time schedule.
    So what will be the near future of E@H? Will we crunch BRP1 tasks on our CPUs, which is much less effective?

    For a short answer we will be pleased.

    Kind regards and happy crunching
    Martin

    P.S.: I found the "LSC-Virgo data analysis white paper" still very much interesting.
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    Message 119874 - Posted 1 Nov 2012 14:57:38 UTC

      Last modified: 1 Nov 2012 15:12:40 UTC

      For fresh data form the Advanced LIGO detectors we will have to wait for another year at minimum


      Correct. But there may still something to be found in the existing data. For "continuous waves" searches the computing power is still what limits the sensitivity of a search, which roughly translates to the depth we could dig into space.

      We are already preparing the next GW search, which will focus fewer promising sky positions, allowing us to reach out further than ever before.


      Will we crunch BRP1 tasks on our CPUs, which is much less effective?


      You think? In contrast to the GW search the Radio-Pulsar search lead to a couple of really interesting new discoveries. In my very personal view this is more effective than the GW searches we did so far.

      We still haven't caught up with Arecibo data production, AFAIK we haven't yet processed any data from 2012. There are still a lot of Radio Pulsars out there waiting to be discovered!

      And finally the Gamma-Ray Pulsar search is suspended because we ran out of manpower, not of data. I hope we can resume that work soon.


      For a short answer we will be pleased.


      Short answer to a long question?


      BM
      astro-marwil
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      Message 119875 - Posted 1 Nov 2012 16:19:18 UTC - in response to Message 119874.

        Hallo BM!
        Thank you for quick answering.

        For "continuous waves" searches the computing power is still what limits the sensitivity of a search, which roughly translates to the depth we could dig into space.

        I believe so. I remember, in early days of EaH we where happy reaching 100GFLOPS, and one task lasted much more than a year to finish. Now we have 7000 times of this crunching power, which gives more freedome for more complex project tasks and longer averaging times, resulting in higher sensitivity.

        In contrast to the GW search the Radio-Pulsar search lead to a couple of really interesting new discoveries. In my very personal view this is more effective than the GW searches we did so far.

        Sorry, my sentence was incomplete. I compared crunching on CPU / GPU. If I remmber correctly the BRP tasks where running for about 10h on CPU instead of some 10min on GPU. Comparing the requiered electrical power to crunch 1 BRP task, I suggest the GPU is also in forehand. Did someone test this? The figure is highly dependend on the used hardware.

        We are already preparing the next GW search, which will focus fewer promising sky positions, allowing us to reach out further than ever before.

        ..... I hope we can resume that work soon.

        We´re happy to heare this and do wait.

        Kind regards and happy crunching
        Martin
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        Message 119876 - Posted 1 Nov 2012 16:45:11 UTC - in response to Message 119874.

          You think? In contrast to the GW search the Radio-Pulsar search lead to a couple of really interesting new discoveries. In my very personal view this is more effective than the GW searches we did so far.

          So, Einstein@Home can profit from the results of pulsar hunting?
          I always thought that this secondary project only diverts the resources.
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          Message 119879 - Posted 1 Nov 2012 19:46:33 UTC - in response to Message 119876.

            Last modified: 1 Nov 2012 20:12:21 UTC

            You think? In contrast to the GW search the Radio-Pulsar search lead to a couple of really interesting new discoveries. In my very personal view this is more effective than the GW searches we did so far.


            So, Einstein@Home can profit from the results of pulsar hunting?
            I always thought that this secondary project only diverts the resources.


            The ultimate goal of Einstein@Home is to contribute to a better understanding of our universe by studying neutron stars, objects with such extreme conditions that they drive our theories of matter and forces to the limits (and possibly beyond), allowing to test and refine these.

            The only way we can study these objects is through their emissions we could detect on (or near) earth - electromagnetic waves (like radio or gamma) or gravitational waves.

            In that sense every result, in particular every new discovery of a pulsar, helps a bit to understand - what is possible, and what not, which theories and models do match best what we observe. So all three searches currently running on Einstein@Home do help the general goal.

            As for the more narrow goal of detecting gravitational waves, the radio pulsar discoveries of Einstein@Home do help to form pulsar timing arrays that will help us to measure gravitational waves of a different wavelength than what the LIGO detectors and the GW search on Einstein@Home is sensitive for.

            Finally the radio pulsar search allows us to keep and even increase our user base and thus computing power, even during periods when there is no new data from the GW detectors available - like now.

            BM
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            Message 119881 - Posted 1 Nov 2012 20:17:03 UTC - in response to Message 119875.

              Last modified: 1 Nov 2012 20:17:31 UTC

              In contrast to the GW search the Radio-Pulsar search lead to a couple of really interesting new discoveries. In my very personal view this is more effective than the GW searches we did so far.

              Sorry, my sentence was incomplete. I compared crunching on CPU / GPU. If I remmber correctly the BRP tasks where running for about 10h on CPU instead of some 10min on GPU. Comparing the requiered electrical power to crunch 1 BRP task, I suggest the GPU is also in forehand. Did someone test this? The figure is highly dependend on the used hardware.


              So you meant 'efficient' instead of 'effective'.

              BM
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              Message 119882 - Posted 1 Nov 2012 21:48:56 UTC

                Last modified: 1 Nov 2012 23:24:18 UTC

                I remember the radio pulsar search as being initiated to solve several problems : an unavoidable hiatus in new data from the IFO's ie. keep the punters interested while we await GW detector upgrades, to help the PALFA consortium's need for processing their data, and to orthogonally study the same class of stars/systems as GW's will anyway. The gamma search is along the same lines.

                If that understanding is correct then : the radio and gamma work have done brilliantly. As for whether it is 'correct' for the E@H project to have solved such issues is a higher question. In any case the value of GW work has not been lost, indeed upper limits have now been placed on certain signal types ( of interest to observers and theorists alike ) not to mention an enormous slab of valuable experience in running the analysis 'pipeline' that E@H is a part of. For the first, or for that matter subsequent, GW detections then validation and confidence in the entire enterprise will be crucial.

                As a 'leading edge' activity I think it is quite reasonable & healthy to assess directions from time to time, to reflect upon progress or otherwise and try to make good guesses for the future. Else it wouldn't be called 'research' would it ?? :-)

                Cheers, Mike.
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                Message 120271 - Posted 21 Nov 2012 10:08:56 UTC - in response to Message 119874.

                  We are already preparing the next GW search, which will focus fewer promising sky positions, allowing us to reach out further than ever before.


                  Actually we will first extend the current S6 LineVeto search a bit to higher frequencies.

                  A number of recent publications and own results of pulsar searches (in radio and gamma-ray) lead us to think that there is a larger population of 'younger' (i.e. faster spinning) pulsars than we expected when we initially set up the search.

                  Note that this is another example of interaction between the different pulsar searches on Einstein@Home.

                  BM
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                  Message 120490 - Posted 27 Nov 2012 7:37:29 UTC - in response to Message 120271.

                    We are already preparing the next GW search, which will focus fewer promising sky positions, allowing us to reach out further than ever before.


                    Actually we will first extend the current S6 LineVeto search a bit to higher frequencies.

                    A number of recent publications and own results of pulsar searches (in radio and gamma-ray) lead us to think that there is a larger population of 'younger' (i.e. faster spinning) pulsars than we expected when we initially set up the search.

                    Note that this is another example of interaction between the different pulsar searches on Einstein@Home.

                    BM

                    Bernd what frequencies are we going out to ? Do we still have the WU count per frequency going like quadratic to frequency ?

                    Cheers, Mike.
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                    Message 120493 - Posted 27 Nov 2012 10:56:38 UTC - in response to Message 120490.

                      Last modified: 27 Nov 2012 10:56:59 UTC

                      Bernd what frequencies are we going out to ?


                      This is still being discussed. Most likely an additional 50Hz or so. The higher we get, the more we would need to include a possible 2nd order frequency derivative. Our current code should be able to do that, but that hasn't been (sufficiently) validated yet.

                      Do we still have the WU count per frequency going like quadratic to frequency ?


                      Yes, as long as we stick to only first frequency derivative ("spindown").

                      We are currently working on the Application. It will be only slightly different, returning two result files, one containing the older "2F" statistics, the other containing the newer "LV". In principle we are extending both previous runs (S6LV1 and S6Bucket) at once.

                      BM
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                      Message 120522 - Posted 27 Nov 2012 22:41:06 UTC

                        Ah I see. Not only faster spinning, but faster evolving too.

                        Cheers, Mike
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                        Message 121658 - Posted 28 Dec 2012 14:36:40 UTC

                          We'll continue with the BRP4 search indefinitely. First we need to catch up with the data backlog of about 13,000 beams (this will take a couple of months at the current rates) then we'll continue in the steady-state. PALFA is taking about 50 new beams of data per day, on the average, so this search will be running for some years, at least for as long as PALFA is collecting new data.


                          Since we are processing an average of 150beams/day, does that mean that we are going to have a shortage of BRP4 tasks to feed all the GPU´s?
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                          Message 121664 - Posted 29 Dec 2012 13:26:12 UTC - in response to Message 121658.

                            Last modified: 29 Dec 2012 13:45:44 UTC

                            We'll continue with the BRP4 search indefinitely. First we need to catch up with the data backlog of about 13,000 beams (this will take a couple of months at the current rates) then we'll continue in the steady-state. PALFA is taking about 50 new beams of data per day, on the average, so this search will be running for some years, at least for as long as PALFA is collecting new data.


                            Since we are processing an average of 150beams/day, does that mean that we are going to have a shortage of BRP4 tasks to feed all the GPU´s?


                            Not necessarily.

                            - The 13,000 beams (now rather 10,000) refer to the data that has been so far copied to the AEI. There is a bit more data to fetch from Cornell (~6000 beams IIRC).

                            - We could widen the parameter space that the data is searched for. This will give us more workunits per data.

                            - There is an OpenCL version of the Gamma-Ray pulsar search being actively worked on, I think it should be ready before the BRP search catches up with the Arecibo data.

                            - There is also (yet) another attempt to make use of the GPUs for the GW search, but this will take a little longer. Certainly not for the planned "extension" run, but possibly for the next; if not ready for the run's start, then we still might issue it when the run's in progress.

                            - While at it, the GW "extension" run will be named "S6BucketLVE". It has been successfully tested over on Albert and the launch on Einstein is projected for Jan 9.

                            BM
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                            Message 121666 - Posted 29 Dec 2012 14:13:19 UTC

                              Thanks for the detalhed answer Bernd.

                              It's good to have a project who comunicate this well with the crunchers.

                              Filipe
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                              Message 123188 - Posted 2 Mar 2013 12:17:58 UTC

                                Last modified: 2 Mar 2013 12:18:09 UTC

                                - Are you catching up wit the the Arecibo data?

                                - Is there any news about the open cl app for the Gamma Ray shearch?
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                                Message 123193 - Posted 2 Mar 2013 16:21:46 UTC - in response to Message 123188.

                                  - Are you catching up wit the the Arecibo data?

                                  - Is there any news about the open cl app for the Gamma Ray shearch?


                                  Hi!

                                  As for the Gamma Ray search, I think we can expect to start a full test of an app on Albert@Home in the next 7- 10 days or so.

                                  Cheers
                                  HB

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                                  Message 123400 - Posted 11 Mar 2013 16:25:51 UTC - in response to Message 123188.

                                    - Are you catching up wit the the Arecibo data?


                                    The time until we catch up with the backlog of Arecibo data is roughly shown by the "Days to process remaining data" on the Server status page.

                                    We're currently gathering more data to keep our analysis pipeline fed, e.g. from another survey of the Parkes telescope.

                                    BM
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                                    Message 123515 - Posted 18 Mar 2013 10:20:35 UTC - in response to Message 123193.

                                      As for the Gamma Ray search, I think we can expect to start a full test of an app on Albert@Home in the next 7- 10 days or so.


                                      FGRP2 OpneCL App launched on Albert.

                                      BM
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                                      Message 123516 - Posted 18 Mar 2013 10:49:27 UTC - in response to Message 123515.



                                        FGRP2 OpneCL App launched on Albert.

                                        BM


                                        Thank you to inform us. However I have a question.
                                        Is this new application for ati only? Certainly, we'd like to have something similar for Nvidia.

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                                        Message 123517 - Posted 18 Mar 2013 11:09:39 UTC

                                          See the related thread on Albert@Home.

                                          BM

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                                          Message 123577 - Posted 21 Mar 2013 11:43:08 UTC - in response to Message 123400.

                                            We're currently gathering more data to keep our analysis pipeline fed, e.g. from another survey of the Parkes telescope.


                                            This is done as a new "application" (in BOINC terms) that will get the new label "BRP5". It is currently being tested on Albert, too ("Binary Radio Pulsar Search (Perseus Arm Survey)").

                                            BM
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                                            Message 123642 - Posted 25 Mar 2013 15:31:21 UTC - in response to Message 123577.

                                              We're currently gathering more data to keep our analysis pipeline fed, e.g. from another survey of the Parkes telescope.


                                              This is done as a new "application" (in BOINC terms) that will get the new label "BRP5". It is currently being tested on Albert, too ("Binary Radio Pulsar Search (Perseus Arm Survey)").


                                              There's some more info over here.

                                              BM
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                                              Message 125872 - Posted 19 Jul 2013 15:37:31 UTC - in response to Message 119879.

                                                You think? In contrast to the GW search the Radio-Pulsar search lead to a couple of really interesting new discoveries. In my very personal view this is more effective than the GW searches we did so far.


                                                So, Einstein@Home can profit from the results of pulsar hunting?
                                                I always thought that this secondary project only diverts the resources.


                                                The ultimate goal of Einstein@Home is to contribute to a better understanding of our universe by studying neutron stars, objects with such extreme conditions that they drive our theories of matter and forces to the limits (and possibly beyond), allowing to test and refine these.

                                                The only way we can study these objects is through their emissions we could detect on (or near) earth - electromagnetic waves (like radio or gamma) or gravitational waves.

                                                In that sense every result, in particular every new discovery of a pulsar, helps a bit to understand - what is possible, and what not, which theories and models do match best what we observe. So all three searches currently running on Einstein@Home do help the general goal.

                                                As for the more narrow goal of detecting gravitational waves, the radio pulsar discoveries of Einstein@Home do help to form pulsar timing arrays that will help us to measure gravitational waves of a different wavelength than what the LIGO detectors and the GW search on Einstein@Home is sensitive for.

                                                Finally the radio pulsar search allows us to keep and even increase our user base and thus computing power, even during periods when there is no new data from the GW detectors available - like now.

                                                BM


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                                                Message 125873 - Posted 19 Jul 2013 15:48:55 UTC - in response to Message 119874.

                                                  The ultimate goal of Einstein@Home is to contribute to a better understanding of our universe by studying neutron stars, objects with such extreme conditions that they drive our theories of matter and forces to the limits (and possibly beyond), allowing to test and refine these.


                                                  Boy am I in the wrong place. I thought we were trying to find and contact ET's...come to think of it, I think this has already been done..



                                                  No reply needed. It would only start trouble :)
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                                                  Message 131535 - Posted 16 Jun 2014 10:41:41 UTC

                                                    Any update?

                                                    What is coming after S6 casa and FGRP3?
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                                                    Message 131537 - Posted 16 Jun 2014 11:40:12 UTC - in response to Message 131535.

                                                      FGRP3 was originally meant to process the new data published by FERMI last November. However at the launch of FGRP3, we couldn't finish the preparation of this data for our search, so we launched FGRP3 first to finish the analysis of the older data set that was left over from the previous run FGRP2. When the current FGRP3 runs out of that data, we intend to have the new data prepared. Work on that is well underway. Also we are working on improvements on the analysis code that will give us an increase in sensitivity of ~25% without additional computing cost.

                                                      S6CasA is actually part of a larger effort that we internally call "S6Directed", i.e. an analysis of "S6" data targeting single positions (hopefully GW sources) in the sky. We started with the most promising "Cassiopeia A", and will then simply move on to the next target (there are about a dozen on our list). We are also working on improving the analysis code for this, trying to make it more efficient and sensitive.

                                                      BM

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                                                      Message 131538 - Posted 16 Jun 2014 13:06:05 UTC

                                                        (there are about a dozen on our list)


                                                        12 targets. Uau! This is going to take some serious computing power.

                                                        S6 casa is running for more than a year now.
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                                                        Message 131542 - Posted 16 Jun 2014 19:25:00 UTC - in response to Message 131538.

                                                          Last modified: 16 Jun 2014 19:25:56 UTC

                                                          Well, we intend to spend less time on the other targets than we did on CasA, and we hope that the more efficient search code will help to not lose too much sensitivity. We also probably won't cover all possible sources; we will probably cut the run short when more sensitive data from the advanced detectors becomes available for analysis, which is currently planned to happen end of next year.

                                                          BM

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                                                          Message 131543 - Posted 16 Jun 2014 21:24:58 UTC - in response to Message 131537.

                                                            Last modified: 16 Jun 2014 21:31:22 UTC

                                                            Hallo!

                                                            We started with the most promising "Cassiopeia A", and will then simply move on to the next target (there are about a dozen on our list).

                                                            I would like to know, what is so promissing on Cassiopeia A. It´s not sure whether it´s a black hole or a pulsar, whose magnetic axis is never directed to earth, as the radition activity doesn´t show a measurable periodicity. Where as the Crab-Pulsar is just 57% as far away as Cas A and so giving 3 times stronger GW signal, Further the Crab-Pulsar is also a young pulsar, just about 1000 years old, and does show glitches in the rotation periode, which are interpreted as reorientation of his material. This should result in GWs, ok? Furthermore the Crab-Pulsar is realy very well controlled by the Jodrell Bank Observatory. So one do know the exact period at that time and when such glitches happend and how strong they are. So the Crab-Pulsar would have been on the top of my list.
                                                            Kind regards an happy crunching
                                                            Martin
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                                                            Message 131621 - Posted 20 Jun 2014 14:51:10 UTC - in response to Message 131543.

                                                              Hallo!
                                                              We started with the most promising "Cassiopeia A", and will then simply move on to the next target (there are about a dozen on our list).

                                                              I would like to know, what is so promissing on Cassiopeia A. It´s not sure whether it´s a black hole or a pulsar, whose magnetic axis is never directed to earth, as the radition activity doesn´t show a measurable periodicity. Where as the Crab-Pulsar is just 57% as far away as Cas A and so giving 3 times stronger GW signal, Further the Crab-Pulsar is also a young pulsar, just about 1000 years old, and does show glitches in the rotation periode, which are interpreted as reorientation of his material. This should result in GWs, ok? Furthermore the Crab-Pulsar is realy very well controlled by the Jodrell Bank Observatory. So one do know the exact period at that time and when such glitches happend and how strong they are. So the Crab-Pulsar would have been on the top of my list.
                                                              Kind regards an happy crunching
                                                              Martin


                                                              That is exactly the point: Because the rotation of the Crab-pulsar is so well understood, it doesn't take a massive network of computers like Einstein@home to search for GWs from it (at least as long as you assume that the GW frequency is related to the EM pulse frequency in a known way (like the first being twice the latter for a certain emission mechanism), which is a reasonable assumption, but by no means certain). So most searches involving the Crab-pulsar are "targeted" or "narrow band" searches, where the search frequency and frequency derivatives of the GW signal are very tightly constrained by EM observations. So this kind of search is not that computationally expensive.

                                                              For Cas A however, as you mentioned, this is not the case. So we need to do a much more expensive "directed" search here. The sky position of the source is known from EM observations, but for the frequency and frequency derivative(s), we need to try an awful lot of independent templates, and that's what Einstein@home can do really well.

                                                              HB

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                                                              Message 131721 - Posted 24 Jun 2014 20:59:56 UTC - in response to Message 131621.

                                                                Last modified: 24 Jun 2014 21:01:16 UTC

                                                                Hallo Bikeman!

                                                                Hallo!

                                                                We started with the most promising "Cassiopeia A", and will then simply move on to the next target (there are about a dozen on our list).


                                                                I would like to know, what is so promissing on Cassiopeia A. It´s not sure whether it´s a black hole or a pulsar, whose magnetic axis is never directed to earth, as the radition activity doesn´t show a measurable periodicity. Where as the Crab-Pulsar is just 57% as far away as Cas A and so giving 3 times stronger GW signal, Further the Crab-Pulsar is also a young pulsar, just about 1000 years old, and does show glitches in the rotation periode, which are interpreted as reorientation of his material. This should result in GWs, ok? Furthermore the Crab-Pulsar is realy very well controlled by the Jodrell Bank Observatory. So one do know the exact period at that time and when such glitches happend and how strong they are. So the Crab-Pulsar would have been on the top of my list. Furthermore, doesn´t these glitches - abrupt changes in rotational speed - emit GW-power?
                                                                Kind regards an happy crunching
                                                                Martin

                                                                ..... So most searches involving the Crab-pulsar are "targeted" or "narrow band" searches, where the search frequency and frequency derivatives of the GW signal are very tightly constrained by EM observations. So this kind of search is not that computationally expensive. ....

                                                                From this I conclude, that it was already for a limited range of parameters done without success. So, will it be repeated here with a much wider field of parameters? Furthermore, doesn´t these glitches - abrupt changes in rotational speed likely due to material reorientation inside the pulsar - emit GW-power?

                                                                Kind regards and happy crunching
                                                                Martin
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                                                                Message 131732 - Posted 25 Jun 2014 9:51:50 UTC - in response to Message 131721.


                                                                  From this I conclude, that it was already for a limited range of parameters done without success. So, will it be repeated here with a much wider field of parameters? Furthermore, doesn´t these glitches - abrupt changes in rotational speed likely due to material reorientation inside the pulsar - emit GW-power?

                                                                  Kind regards and happy crunching
                                                                  Martin


                                                                  At this point I have to caution that I'm not a physicist, but hey, I can point you to what physicists have done:

                                                                  GW searches for the Crab pulsar:

                                                                  A presentation with a birds-eye view of observational results,

                                                                  http://gr20-amaldi10.edu.pl/userfiles/12-01_Marie Anne Bizouard - Observational Results from Ground-based___.pdf

                                                                  A pointer to results for Crab pulsar and Vela pulsar (another well studied young pulsar and a real champion when it comes to glitching) is on page 44:

                                                                  Vela: Astrophys. J. 737 (2011) 93 : http://iopscience.iop.org/0004-637X/737/2/93/
                                                                  Crab and others: Astrophys. J. 713 (2010) 671 : http://iopscience.iop.org/0004-637X/713/1/671/

                                                                  There might be newer studies but you will get an idea from those papers.

                                                                  You will also easily find papers that discuss how/if pulsar glitches (and whatever happens before or after the glitch) might cause detectable GWs:


                                                                  PhysRevD.84.023007, also on http://arxiv.org/pdf/1104.1704.pdf


                                                                  http://www.phys.ufl.edu/ireu/IREU2013/pdf_reports/Corey_Bathurst_Final_Report.pdf


                                                                  I'm not aware of any plans to do narrow-band or even targeted searches for Einstein@Home. That's simply not the kind of search we are specializing in, E@H is better at all-sky searches or directed searches if you are looking for continuous gravitational waves.

                                                                  Cheers
                                                                  HB

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                                                                  Message 131753 - Posted 26 Jun 2014 3:28:14 UTC

                                                                    Last modified: 26 Jun 2014 3:36:39 UTC

                                                                    Well, I'm game ! :-0

                                                                    My reading of Prix et al seems to indicate that glitching can have a detectable GW signature(s), under the curious title of 'transient continuous waves'. These are further subdivided into 'repeating' and 'non-repeating' transient continuous waves. :-)

                                                                    This appears to mean that processes either causative to, or consequent upon, the glitching events generate GW emission regularities that decay in amplitude over far shorter time periods ( eg. weeks ) than the typical winding down behaviour of the spinning neutron star. That in turn depends upon the physics, or model thereof, applied to the problem.

                                                                    As for all the Bayesian stuff : aarggh .... I've never really grasped Bayes .... :-(

                                                                    However for us simple souls there is ( my emphasis ) :

                                                                    In addition to the fully coherent search method, we have derived the necessary formalism for a semi-coherent transient search, which could be used to perform an all-sky, all-frequency wide parameter-space transient search, for example running on Einstein@Home. More work is required to fully develop and implement this approach.

                                                                    Cheers, Mike.

                                                                    ( edit ) As far as I can tell : one takes the 'standard' continuous wave model and looks at detection within shorter 'windows'. This necessarily affects the detection statistics, or if you like, the confidence that one can place upon a positive result from a given template actually being evidence for a real phenomenon in the sky. That is : what likelihood may be assigned to us being fooled by random/uncorrelated noise.
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                                                                    Message 132072 - Posted 9 Jul 2014 9:10:57 UTC - in response to Message 131732.

                                                                      Last modified: 9 Jul 2014 9:11:29 UTC

                                                                      I'm not aware of any plans to do narrow-band or even targeted searches for Einstein@Home. That's simply not the kind of search we are specializing in, E@H is better at all-sky searches or directed searches if you are looking for continuous gravitational waves.


                                                                      The main argument here is that these searches have a computing time / data volume ratio that make these infeasible for volunteer computing. Your computers will spend more time on downloading data for a task than on computing it.

                                                                      BM
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                                                                      Message 132073 - Posted 9 Jul 2014 9:19:45 UTC - in response to Message 131537.

                                                                        Last modified: 10 Jul 2014 7:34:23 UTC

                                                                        S6CasA is actually part of a larger effort that we internally call "S6Directed", i.e. an analysis of "S6" data targeting single positions (hopefully GW sources) in the sky. We started with the most promising "Cassiopeia A", and will then simply move on to the next target (there are about a dozen on our list). We are also working on improving the analysis code for this, trying to make it more efficient and sensitive.


                                                                        Update on that: At present it looks like there will be numerous and substantial changes to the analysis application code which effect e.g. on the runtime behavior are difficult to foresee. We will probably have a series of short "engineering runs" to get a better understanding of the new code in the heterogeneous environment of Einstein@Home before we will continue with actual searches.

                                                                        BM
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                                                                        Message 132094 - Posted 10 Jul 2014 6:35:23 UTC - in response to Message 132073.

                                                                          Last modified: 10 Jul 2014 6:35:59 UTC

                                                                          .... to get a better understanding of the new code in the heterogeneous environment of Einstein@Home ....

                                                                          Yes. Experience has shown the ability of the E@H milieu to step upon the mines in the field. :-)

                                                                          Cheers, Mike.
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                                                                          Message 132402 - Posted 23 Jul 2014 9:47:40 UTC - in response to Message 132073.

                                                                            Another update: still under heavy discussion and thus quite preliminary, but it currently looks like after the current S6CasA "directed" run we will squeeze in a short (1-2 month) run where we will follow-up a few (million) candidates from the S6Bucket runs. The remaining ~45d S6CasA look a bit tight to set one up, but essentially we would just need a new workunit generator - data, application, validator etc. are still there from the original run. At least a follow-up run would fit much better in now than interrupting or having to wait for the end of the next "science run".

                                                                            BM

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                                                                            Message 136739 - Posted 22 Dec 2014 22:07:36 UTC

                                                                              Hello,
                                                                              What´s planed after FGRP4 run?

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                                                                              Message 136753 - Posted 23 Dec 2014 10:23:17 UTC - in response to Message 136739.

                                                                                Hallo Majo!
                                                                                Please look for this thread.

                                                                                Merry Christmas and a happy New Year!

                                                                                Kind regards and happy crunching
                                                                                Martin
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                                                                                Message 136757 - Posted 23 Dec 2014 11:32:21 UTC

                                                                                  Last modified: 23 Dec 2014 11:36:10 UTC

                                                                                  We will get more data for FGRP4, so the run will last longer than what is currently shown at the server status page.

                                                                                  However all current searches are chewing old data, and neither Arecibo nor Fermi produce enough new data to keep Einstein@Home continuously fed from these.

                                                                                  Work on the advanced LIGO detectors is well underway, and they should start taking "scientific" data soon. Perspectively during 2015 the focus of Einstein@Home will shift back to its original purpose, the analysis of data from gravitational wave observatories.

                                                                                  BM

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                                                                                  Message 136791 - Posted 24 Dec 2014 10:49:27 UTC

                                                                                    What is planned after the current BRP5 run from the Parkes radio telescope in Australia?
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                                                                                    Message 138001 - Posted 28 Jan 2015 22:19:27 UTC - in response to Message 136791.

                                                                                      Last modified: 29 Jan 2015 10:06:54 UTC

                                                                                      What is planned after the current BRP5 run from the Parkes radio telescope in Australia?


                                                                                      It took us a while to decide on that. Currently planned is to re-analyze data from PMPS (Parkes Multi-beam Pulsar Survey) with a much larger parameter space that we can now cover using GPUs. The data itself is pretty old, but in BRP3 we already found 24 unknown pulsars that escaped earlier analysis. Maybe there's still more to find in there.

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                                                                                      Message 138006 - Posted 29 Jan 2015 9:36:23 UTC

                                                                                        Thanks to inform us. Mutch apreciated.
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                                                                                        Message 138145 - Posted 6 Feb 2015 9:09:51 UTC

                                                                                          Last modified: 17 Feb 2015 6:16:18 UTC

                                                                                          Here's a bit more:

                                                                                          - Radio pulsar (GPU) search: preparation of the successor to BRP5 (named - surprise! - BRP6) is underway. As I wrote, this will be another sift through PMPS data, with extended parameter space, mainly up to higher frequency.

                                                                                          - Gravitational Wave searches: after the "S6Bucket Follow-Up #1" run we will have a second follow-up run, further narrowing down (30-50% of the candidates, 10% of the sky region, 2-3x longer coherent integration time). Preparation is already underway, although a few things, e.g. the actual number of candidates, can only be determined after the current run has finished. This second stage follow-up run is planned to take most (~90%) of the CPU computing power on Einstein@Home, the Gamma-Ray search will be reduced to a minimum (default) share.

                                                                                          - Gamma-Ray search: Due to an error in pre-processing too few workunits have been produced for the last 50 or so "file sets" of FGRP4. While this has been corrected for the "file sets" that haven't been touched until about a week ago, we need to re-do a couple of sets afterwards. At current share of ~50% CPU computing power this would take another ~2 months of FGRP4 beyond what's currently shown at the server status page. However taking into account the planned lowering of the FGRP share in favor of GW search, I think FGRP4 will continue at least for another half year.

                                                                                          BM

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                                                                                          Message 138162 - Posted 7 Feb 2015 8:54:53 UTC

                                                                                            Due to an error in pre-processing too few workunits have been produced for the last 50 or so "file sets" of FGRP4. While this has been corrected for the "file sets" that haven't been touch until about a week ago, we need to re-do a couple of sets afterwards.

                                                                                            Bernd, could you clarify, did we lost some data or did we process something incorrectly?
                                                                                            And since we are talking about it, could you please briefly explain how FGRP pipeline works?
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                                                                                            Message 138175 - Posted 8 Feb 2015 8:02:10 UTC - in response to Message 138162.

                                                                                              Due to an error in pre-processing too few workunits have been produced for the last 50 or so "file sets" of FGRP4. While this has been corrected for the "file sets" that haven't been touch until about a week ago, we need to re-do a couple of sets afterwards.

                                                                                              Bernd, could you clarify, did we lost some data or did we process something incorrectly?
                                                                                              And since we are talking about it, could you please briefly explain how FGRP pipeline works?

                                                                                              I'll attempt to clarify things from what I understand (I could be wrong on some things but I hope not) as a volunteer, just like yourself. Hopefully, if I get it basically correct, it might save Bernd some time.

                                                                                              Firstly, it's nothing to do with data loss or incorrect processing. When you get an FGRP4 task to process for the first time, you get a data file (eg LATeah0099E.dat for recent tasks) plus a set of parameters to be used by the app in the analysis of the data. You don't see these parameters directly - they are contained in the scheduler reply to your BOINC client's request for work. They get inserted into the state file (client_state.xml) where they will remain ready to be used once that particular task gets to the top of the queue.

                                                                                              Once you have a particular data file, you can get further tasks that use the same file with different parameter sets. This may continue for days or even weeks until the full range of parameter sets have been distributed. Once that happens, the scheduler moves on to the next data file (eg LATeah0100E.dat) and the whole process repeats.

                                                                                              Bernd's message is simply advising that there was some sort of bug in the work generation process so that not all parameter sets were created for approximately the last 50 data files - I'm guessing something like LATeah0049E.dat to LATeah0098E.dat approximately. The current file (LATeah0099E.dat) has lasted for around 8 days now (and may last even longer) so I'm sure all parameter sets are being generated for this data file. The previous data file (LATeah0098E.dat) lasted less than half a day before being replaced by the current file so it would appear to have suffered from the bug.

                                                                                              Now that the problem is known, I imagine it will be a simple matter to go back and generate all the missing parameter sets. This will create a whole bunch of tasks that will extend the life of the FGRP4 run as Bernd was mentioning.

                                                                                              ____________
                                                                                              Cheers,
                                                                                              Gary.
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                                                                                              Message 138176 - Posted 8 Feb 2015 8:34:24 UTC - in response to Message 138175.

                                                                                                Due to an error in pre-processing too few workunits have been produced for the last 50 or so "file sets" of FGRP4. While this has been corrected for the "file sets" that haven't been touch until about a week ago, we need to re-do a couple of sets afterwards.

                                                                                                Bernd, could you clarify, did we lost some data or did we process something incorrectly?
                                                                                                And since we are talking about it, could you please briefly explain how FGRP pipeline works?

                                                                                                I'll attempt to clarify things from what I understand (I could be wrong on some things but I hope not) as a volunteer, just like yourself. Hopefully, if I get it basically correct, it might save Bernd some time.

                                                                                                Firstly, it's nothing to do with data loss or incorrect processing. When you get an FGRP4 task to process for the first time, you get a data file (eg LATeah0099E.dat for recent tasks) plus a set of parameters to be used by the app in the analysis of the data. You don't see these parameters directly - they are contained in the scheduler reply to your BOINC client's request for work. They get inserted into the state file (client_state.xml) where they will remain ready to be used once that particular task gets to the top of the queue.

                                                                                                Once you have a particular data file, you can get further tasks that use the same file with different parameter sets. This may continue for days or even weeks until the full range of parameter sets have been distributed. Once that happens, the scheduler moves on to the next data file (eg LATeah0100E.dat) and the whole process repeats.

                                                                                                Bernd's message is simply advising that there was some sort of bug in the work generation process so that not all parameter sets were created for approximately the last 50 data files - I'm guessing something like LATeah0049E.dat to LATeah0098E.dat approximately. The current file (LATeah0099E.dat) has lasted for around 8 days now (and may last even longer) so I'm sure all parameter sets are being generated for this data file. The previous data file (LATeah0098E.dat) lasted less than half a day before being replaced by the current file so it would appear to have suffered from the bug.

                                                                                                Now that the problem is known, I imagine it will be a simple matter to go back and generate all the missing parameter sets. This will create a whole bunch of tasks that will extend the life of the FGRP4 run as Bernd was mentioning.


                                                                                                Okay, now I see. Much appreciated, Gary!
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                                                                                                Message 138178 - Posted 8 Feb 2015 10:52:10 UTC - in response to Message 138145.

                                                                                                  - Radio pulsar (GPU) search: preparation of the successor to BRP5 (named - surprise! - BRP6) is underway. As I wrote, this will be another sift through PMPS data, with extended parameter space, mainly up to higher frequency.


                                                                                                  Einstein preferences now lists Parkes. Server Status lists BRP6. Applications page lists Parkes as BRP5.

                                                                                                  Is Parkes BRP6 or are we looking at Parkes and BRP6 as separate projects?
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                                                                                                  Message 138184 - Posted 8 Feb 2015 15:29:19 UTC - in response to Message 138178.

                                                                                                    Last modified: 8 Feb 2015 15:30:26 UTC

                                                                                                    Applications page lists Parkes as BRP5.

                                                                                                    Is Parkes BRP6 or are we looking at Parkes and BRP6 as separate projects?


                                                                                                    The reference to "BRP5" that you see on the Applications page is just in the name of the "plan-class". It's basically a name for a filter condition that will assign the "best" application version to your host depending on your hardware and software. Those filter-conditions are the same for BRP5 and BRP6, so they were just re-used for BRP6. We could have copied and renamed them, but that would make it quite a bit harder to maintain the configuration.

                                                                                                    So the new search on Parkes data is definitely called BRP6, no matter what the plan class for the apps are named. I hope this is not too confusing.

                                                                                                    Cheers
                                                                                                    HB
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                                                                                                    Message 138186 - Posted 8 Feb 2015 18:00:49 UTC - in response to Message 138184.

                                                                                                      A bit confusing but understanding it. Thanks for the answer.
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                                                                                                      Message 138203 - Posted 9 Feb 2015 14:01:25 UTC - in response to Message 138175.

                                                                                                        Thanks, Gary!

                                                                                                        BM

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                                                                                                        Message 138207 - Posted 9 Feb 2015 15:35:16 UTC

                                                                                                          Hi all,

                                                                                                          the following is to give you a bit more background on the new binary radio pulsar search "BRP6" aka "PMPS XT" is about. The data your GPUs will be analyzing are archival observations from the Parkes Telescope in Australia, from the very successful Parkes Multi-beam Pulsar Survey (PMPS).

                                                                                                          The very same data set has been previously analyzed using Einstein@Home in the BRP3 (PMPS) , which led to the discovery of 24 new radio pulsars, including quite a few interesting ones. You can read up on all the details and discoveries in the publication "Einstein@Home Discovery of 24 Pulsars in the Parkes Multi-beam Pulsar Survey", which is available for free on the arXiv.

                                                                                                          When we planned and conducted this first analysis we where limited by the available computing power on Einstein@Home, which at that time forced us to limit our search to pulsars spinning with at most 130 Hz. Searching for faster spinning pulsars in binaries requires more templates, and the dependence on the spin frequency is pretty steep (f^3 for the experts). In the concluding paragraphs of the publication we speculated on what kind of searches we might be able to do in the future, assuming the usual (Moore's law) growth in computing power over time. Extrapolating from the computing power and apps back the we estimated that within a decade we would be able to re-do our analysis and search up to 250 Hz.

                                                                                                          Here we are, a bit more than four years after the start of the BRP3 PMPS search. Improvements in the Nvidia BRP GPU apps and the development of an ATI/AMD GPU app allow us to already now extend our search range up to pulsar spin frequencies of 300 Hz. And that is precisely what BRP6 will do. With your help we will re-analyze the PMPS data and look for faster spinning pulsars in tight binary systems. Scientifically speaking, this is very interesting territority: fast-spinning (millisecond) pulsars in short-orbital-period binaries are an extremely exciting class of astronomical objects. One can do precise tests of general relativity with them, study stellar evolution, and get a more complete picture of the pulsar population in our Galaxy.

                                                                                                          The PMPS data set still is quite large with over 41,000 individual observations. At the current computing power it would take about three years to conduct this very thorough analysis that nobody has ever done before. During this time, however, if the available computing power keeps growing as expected, the actual time to completion will be less.


                                                                                                          Thank you for your support, keep on crunching,
                                                                                                          Benjamin
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                                                                                                          Message 138219 - Posted 9 Feb 2015 17:17:28 UTC - in response to Message 138207.

                                                                                                            Thank you for your comprehensive information.

                                                                                                            ...Improvements in the Nvidia BRP GPU apps and the development of an ATI/AMD GPU app allow us to already now extend our search range up to pulsar spin frequencies of 300 Hz...

                                                                                                            Imagine what we could achieve with applications utilizing newer versions of CUDA, OpenCL or AVX.
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                                                                                                            Message 138230 - Posted 9 Feb 2015 17:57:37 UTC

                                                                                                              I just put a new cruncher online and after reading the post by Benjamin I'm ordering parts for another new one.

                                                                                                              This is exciting information, keep it coming when you can. It is very much appreciated.

                                                                                                              Phil


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                                                                                                              Message 138234 - Posted 9 Feb 2015 20:44:55 UTC - in response to Message 138207.

                                                                                                                Is this new application limited to GPUs only? I would like to help out with my CPUs.

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                                                                                                                Message 138250 - Posted 10 Feb 2015 1:55:13 UTC

                                                                                                                  Last modified: 10 Feb 2015 4:30:32 UTC

                                                                                                                  Hi Ben ! This is all great news. May we find yet more rare birds .... :-)

                                                                                                                  Once upon a time I meant to ask about that PMPS survey as described in that 2013 E@H 24 pulsar paper ( page 2, section 2. PARKES MULTI-BEAM PULSAR SURVEY AND PREVIOUS ANALYSES ):

                                                                                                                  .... with a total of 3190 telescope pointings (Manchester et al. 2001). Each pointing is comprised of 13 dual-polarization beams. These are arranged in two hexagonal rings, each containing six beams around a central beam, creating a ‘Star-of-David’ pattern (Staveley-Smith et al. 1996). Each observation covers a radio bandwidth of 288 MHz, which is observed in a filterbank of 96 channels each with 3MHz width, centered on 1374 MHz. The sampling time is 250 us and the filterbank data have a dynamic range of 1 bit per sample. Each beam has an integration time of 2097.152 s, with 2^23 time samples. This yields a file size of 100.7MB per beam and a total data volume of 4.1 TB for all filterbank and associated header files.

                                                                                                                  ... I've pretty well got all that except the red highlighted bit. So that's basically an on/off switch, so to speak, for each 3MHz wide channel ? Have I read that right ? It seems rather coarse grained or rather more likely I'm missing something important here.

                                                                                                                  Cheers, Mike.

                                                                                                                  ( edit ) I guess that relates also to the later comment :

                                                                                                                  .... we convert the survey data in filterbank format from 1 bit dynamic range per sample into a file format with 8 bits per sample using ...

                                                                                                                  which I also don't follow. I guess I am thinking that for each given 250 us interval a certain frequency bin collects some number of photons ( of the energy corresponding to the frequency range in the bin ) which is then either above or below some threshold and then assigned a 0 or a 1 accordingly. That can't be right, can it ?
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                                                                                                                  Message 138256 - Posted 10 Feb 2015 6:33:44 UTC - in response to Message 138250.

                                                                                                                    Last modified: 10 Feb 2015 6:35:00 UTC

                                                                                                                    Hi Mike,

                                                                                                                    ... I've pretty well got all that except the red highlighted bit. So that's basically an on/off switch, so to speak, for each 3MHz wide channel ? Have I read that right ? It seems rather coarse grained or rather more likely I'm missing something important here.


                                                                                                                    you have understood this correctly. In the PMPS data taken in the late 1990s, the data were encoded with 1 bit per sample. So at each timestamp (every 250 microseconds), the filterbank computes a radio spectrum of 96 channels covering 288 MHz of bandwidth. The values of that spectrum are stored in 1-bit format, i.e., an on-off switch. As far as I know that did a lot of testing and modelling beforehand and it turns out that you lose only a bit of SNR when encoding data in 1-bit format. Also, it makes your analysis more robust against very loud short-time outliers (like radio frequency interference).

                                                                                                                    You should also keep in mind, that for the actual pulsar searching you will de-disperse the data and sum the values in 96 channels, effectively averaging the 1-bit samples. At this point your resulting de-dispersed (time series) data will not be stored with 1-bit samples!

                                                                                                                    Regarding your other question about the 8-bit conversion issue: The quote from the paper is correct. The conversion only has to happen for technical reasons. The telescope data we feed into the pipeline still has 1 bit per sample, but the piece of code we used for de-dispersion from the standard PRESTO pulsar processing software suite needs 8 bit per sample at least. This is why we simply re-write the 1-bit-per-sample data into 8-bit-per-sample data. This step does not add any resolution or information.

                                                                                                                    Cheers,
                                                                                                                    Benjamin

                                                                                                                    edit: added links
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                                                                                                                    Message 138257 - Posted 10 Feb 2015 8:34:55 UTC - in response to Message 138256.

                                                                                                                      Interesting, so if I understand correctly, it is plain 1-bit sampling (similar to PCM audio) and not a form of PWM (similar to DSD audio) I thought so far?

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                                                                                                                      Message 138258 - Posted 10 Feb 2015 8:49:57 UTC - in response to Message 138257.

                                                                                                                        Hi Sebastian,

                                                                                                                        Interesting, so if I understand correctly, it is plain 1-bit sampling (similar to PCM audio) and not a form of PWM (similar to DSD audio) I thought so far?


                                                                                                                        yup, this is correct. The filterbank generates radio spectra for each time sample. The frequency bins of the radio spectrum contain the intensity (the two orthogonal polarizations squared and summed), and are 1-bit encoded when digitized.


                                                                                                                        Cheers,
                                                                                                                        Benjamin
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                                                                                                                        Message 138266 - Posted 10 Feb 2015 13:35:38 UTC - in response to Message 138219.


                                                                                                                          Imagine what we could achieve with applications utilizing newer versions of CUDA, OpenCL or AVX.


                                                                                                                          AVX: That would be useful only for CPU apps, which we don't plan to have for BRP6 in the foreseeable future.

                                                                                                                          Newer versions of CUDA: Yes, that's on our list of TODOs for the near future, in fact the OSX-CUDA version we are now using for BRP6 is already CUDA 5.5.

                                                                                                                          Newer versions of OpenCL: not sure what to gain from that, but we might want to try a different FFT lib.

                                                                                                                          I also have one or two ideas for further optimizations that would reduce the amount of data transferred over the PCIe bus. As this BRP6 run will last for quite a while, I'm willing to invest some time again to make this more efficient.


                                                                                                                          Cheers
                                                                                                                          HB



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                                                                                                                          Message 138267 - Posted 10 Feb 2015 14:05:17 UTC - in response to Message 138266.

                                                                                                                            AVX: That would be useful only for CPU apps, which we don't plan to have for BRP6 in the foreseeable future.
                                                                                                                            I thought not only about BRP6, but also about other applications/subprojects.

                                                                                                                            Newer versions of CUDA: Yes, that's on our list of TODOs for the near future, in fact the OSX-CUDA version we are now using for BRP6 is already CUDA 5.5.
                                                                                                                            This is good news.

                                                                                                                            Newer versions of OpenCL: not sure what to gain from that, but we might want to try a different FFT lib.
                                                                                                                            I was thinking about using shared memory in APUs, etc.

                                                                                                                            I also have one or two ideas for further optimizations that would reduce the amount of data transferred over the PCIe bus. As this BRP6 run will last for quite a while, I'm willing to invest some time again to make this more efficient.
                                                                                                                            This is even better news.
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                                                                                                                            Message 138283 - Posted 10 Feb 2015 22:28:30 UTC - in response to Message 138256.

                                                                                                                              Last modified: 10 Feb 2015 22:44:23 UTC

                                                                                                                              Thanks Ben, I have my missing bits now. A real signal may still line up in the bins after some de-dispersion attempt, now in 8-bit dynamic range and also remembering that the pulsar emissions are fairly broad across the bands of interest anyway. So that power, added in quadrature, if periodic in the time series can then be caught by Fourier etc. A good statistic plus details from that goes toward new observations to confirm and characterise maybe a new discovery. Actually that makes the process and its proven successes even more impressive! :-) :-)

                                                                                                                              One other question if I may : what's the order of magnitude of a 'typical' dispersion delay ( or the difference b/w that for lowest frequency of interest c/w the highest ) compared to the sampling interval ? Or if you like : what's the general range of how many samples do we shift the data across to successfully get the 'right' emission spectrum ? Hopefully I have worded that right .... ie. I don't know how to convert a delta_DM value to a time delay.

                                                                                                                              Cheers, Mike.
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                                                                                                                              Message 138289 - Posted 11 Feb 2015 8:13:55 UTC - in response to Message 138283.

                                                                                                                                Last modified: 11 Feb 2015 8:14:13 UTC

                                                                                                                                Hi Mike,

                                                                                                                                One other question if I may : what's the order of magnitude of a 'typical' dispersion delay ( or the difference b/w that for lowest frequency of interest c/w the highest ) compared to the sampling interval ? Or if you like : what's the general range of how many samples do we shift the data across to successfully get the 'right' emission spectrum ? Hopefully I have worded that right .... ie. I don't know how to convert a delta_DM value to a time delay.


                                                                                                                                The dispersion delay between two radio frequencies f1 and f2 is

                                                                                                                                delta_t = 4149 secs * (f1^-2 - f2^-2) * DM,

                                                                                                                                where DM is measured in pc/cm^3 and f1 and f2 are measured in MHz. You can divide this by sampling time to get the dispersion time delay delta_t in samples. You can find this formula for example on this handy NRAO webpage. It's also equation (2.43) in the introduction of my PhD thesis.

                                                                                                                                For the PMPS data we have f1= 1230 MHz, f2= 1518 MHz, and for a DM of, say, 200 pc/cm^3 I get delta_t = 0.188 seconds, which corresponds to 753.5 of the 250-microsecond samples.


                                                                                                                                Cheers,
                                                                                                                                Benjamin
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                                                                                                                                Message 138309 - Posted 11 Feb 2015 22:23:18 UTC

                                                                                                                                  Last modified: 11 Feb 2015 23:16:42 UTC

                                                                                                                                  Thank you Ben. Hmmm .. typically hundreds of samples indeed.

                                                                                                                                  Cheers, Mike.

                                                                                                                                  ( edit ) Something's broken with your PhD thesis link @ Harvard but I found this one.
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                                                                                                                                  Message 138315 - Posted 12 Feb 2015 1:26:21 UTC - in response to Message 138207.

                                                                                                                                    Hi all,
                                                                                                                                    the following is to give you a bit more background on the new binary radio pulsar search "BRP6" aka "PMPS XT" is about. The data your GPUs will be analyzing are archival observations from the Parkes Telescope in Australia, from the very successful Parkes Multi-beam Pulsar Survey (PMPS).


                                                                                                                                    Thank you much for the very helpful information regarding the new binary radio pulsar search.

                                                                                                                                    Jeroen
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                                                                                                                                    Message 138656 - Posted 24 Feb 2015 3:45:55 UTC

                                                                                                                                      Last modified: 24 Feb 2015 4:28:55 UTC

                                                                                                                                      I decided to bite the bullet and get a copy of the 'Handbook Of Pulsar Astronomy' by Lorimer & Kramer. I expect that will keep me busy for a while. Having only finished the first - introductory/overview - chapter, the field reminds me of lepidoptery ie. the study of butterflies and moths. I don't mean that in any derogatory sense at all, but rather what a wonderful collection of objects in the pulsar category are out there, and boy are there some weird astrophysical gadgets operating ! I have this image in my mind of these fast, dense rotors just showering sparks all over the neighborhood ie. what a wild place must be the surface of a neutron star. I also note how hungrily one can study all meaningful aspects of the radio emission properties. So far it seems quite well written, not too much of a brain strain. I just have to quote this ( I'm assuming a wee bit tongue-in-cheek ) comment about galactic pulsar distributions :

                                                                                                                                      Although the clustering of sources around the Sun seen in the left panel of Figure 1.9 would be consistent with Ptolemy's geocentric picture of the heavens, it is clearly at variance with what we know about the Galaxy ......



                                                                                                                                      In any event it has already settled my mind about dispersion effects. As this graphic illustrates :



                                                                                                                                      the propagation delays can span several pulse cycles. The other thing that especially strikes me while reading is that neutron stars, being nearly black holes as it were, retain EM visibility for behaviours that may demonstrate really high gravitational field strengths ( yes, I know that is an obvious comment ).

                                                                                                                                      Cheers, Mike.
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                                                                                                                                      Message 138863 - Posted 1 Mar 2015 16:30:42 UTC - in response to Message 138656.

                                                                                                                                        Last modified: 1 Mar 2015 16:34:24 UTC

                                                                                                                                        I decided to bite the bullet and get a copy of the 'Handbook Of Pulsar Astronomy' by Lorimer & Kramer.


                                                                                                                                        Highly readable, and a bit like the "Bible" of the field I guess. Within a few weeks after coming to the AEI I noticed that there was this book that was lying around in quite a lot of offices.

                                                                                                                                        Cheers
                                                                                                                                        HB
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                                                                                                                                        Message 138870 - Posted 2 Mar 2015 4:13:26 UTC - in response to Message 138863.

                                                                                                                                          Last modified: 2 Mar 2015 7:16:35 UTC

                                                                                                                                          I decided to bite the bullet and get a copy of the 'Handbook Of Pulsar Astronomy' by Lorimer & Kramer.


                                                                                                                                          Highly readable, and a bit like the "Bible" of the field I guess. Within a few weeks after coming to the AEI I noticed that there was this book that was lying around in quite a lot of offices.

                                                                                                                                          Cheers
                                                                                                                                          HB

                                                                                                                                          Yeah I sense that. It is quoted so frequently in many papers, and not just from AEI ....

                                                                                                                                          FWIW : I've done chapter 2. I note that the very first extra-solar planet discovery was from around a neutron star ! B1257+12 reported in 1992 ( Wolszczan & Frail ) Roughly one Mercury and two Earths those latter two being in 3:2 resonance. I never knew that !

                                                                                                                                          Cheers, Mike.
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                                                                                                                                          Message 138874 - Posted 2 Mar 2015 8:05:04 UTC - in response to Message 138870.

                                                                                                                                            Last modified: 2 Mar 2015 8:11:35 UTC

                                                                                                                                            http://www.amazon.com/Astronomy-Cambridge-Observing-Handbooks-Astronomers/dp/0521828236

                                                                                                                                            I wondered what size that bullet was so I had to take a look.

                                                                                                                                            I wouldn't mind getting it but at the same time it makes me think I could buy more RAM for that much too.

                                                                                                                                            I guess if my memory was the way it used to be I would buy and read the book

                                                                                                                                            Maybe I will find a free version.

                                                                                                                                            Edit: I found some of the book
                                                                                                                                            http://books.google.com/books/about/Handbook_of_Pulsar_Astronomy.html?id=OZ8tdN6qJcsC
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                                                                                                                                            Message 138877 - Posted 2 Mar 2015 9:06:17 UTC

                                                                                                                                              Last modified: 2 Mar 2015 9:07:59 UTC

                                                                                                                                              There is a relevant article by Duncan Lorimer in Living Reviews In Relativity ( a Max Planck Institute for Gravitational Physics production ) which seems to summarise much of the book.

                                                                                                                                              Cheers, Mike.
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                                                                                                                                              Message 138887 - Posted 2 Mar 2015 13:13:19 UTC - in response to Message 138877.

                                                                                                                                                Hallo!

                                                                                                                                                I guess if my memory was the way it used to be I would buy and read the book

                                                                                                                                                Why buying? Why not lending from a public library? Here in Berlin/Germany that works fine.

                                                                                                                                                There is another wellknown book about : A.G. Lyne, F. Graham-Smith ; Pulsar Astronomy, 4th ed. 2012, Cabridge University Press, 978-1-107-01014-7 (ISBN), €139,65
                                                                                                                                                That´s from the people from Jodrell Bank Observatory, who discovered the first pulsar.
                                                                                                                                                I bought one exemplar of the 2nd ed. very cheep from a second hand bookshop.

                                                                                                                                                Kind regards and happy crunching
                                                                                                                                                Martin
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                                                                                                                                                This material is based upon work supported by the National Science Foundation (NSF) under Grants PHY-1104902, PHY-1104617 and PHY-1105572 and by the Max Planck Gesellschaft (MPG). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the investigators and do not necessarily reflect the views of the NSF or the MPG.

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