Re: [Yade-dev] Do we want low precision float in the gitlab CI pipeline?

2020-03-02 Thread Janek Kozicki (yade) 
OK, thanks :)

And thanks for the link to sudoDEM :)

Bruno Chareyre said: (by the date of Sun, 1 Mar 2020 21:48:19 +0100)

> (sorry for previous empty message)
> Hi,
> I don't think DEM can realistically work with floats. If 100 particles in a
> row are elongated by 0.01%, the relative displacement between the 99th and
> 100th particles is 1e-6 times the positions. With single precision it would
> already produce substantial numerical noise in terms of contact force.
> I mentioned single precision in relation with solving linear systems with
> cholmod, and that part does not support HP.
> I think we can skip the float pipeline. :)
> Cheers
> Bruno
> 
> 
> 
> On Sun, 1 Mar 2020 at 16:24, Janek Kozicki (yade) 
> wrote:
> 
> > Hi,
> >
> > The high precision tests are now running in the gitlab pipeline. And
> > we can be sure that `double` are not getting by accident into master.
> > (except for the modules which are not supported by HP right now [1],
> > in there some `double` could sneak in)
> >
> > This work also makes low-precision possible. I didn't add this to the
> > pipeline, thinking it's not of much use. In some comment Bruno
> > mentioned that some people want to use float in the GPUs to get the
> > results faster. (Whether these results are correct is a topic for a
> > different discussion :)
> >
> > I could prepare a merge request that adds float to the pipeline,
> > because it is compiling (so it works) but it is not passing the tests.
> >
> > The disadvantage is that in many test scripts an exception will have
> > to be written using following distinction:
> >if (yade.config.highPrecisionDecimalPlaces < 7):
> >
> > That's because some of the tests produce different results when float
> > is used, which is not a surprise ;)
> >
> > Currently yade --check has following failures on float:
> >
> > 7  checks are failed
> >   checkColliderConstantness.py
> >   checkViscElEng.py
> >   checkPotentialParticles.py
> >   checkColliderCorrectness.py
> >   checkJCFpm.py
> >   checkWirePM.py
> >   checkCapillaryModels.py
> >
> > And yade --test also has similar errors due to only 6 available
> > decimal places. The log is longer, so I attach it.
> >
> > And most of these failures are because the results are compared with
> > 1e-8 precision, while float maximally can offer 6 decimal places.
> >
> > best regards
> > Janek
> >
> >
> > [1]
> > https://yade-dev.gitlab.io/-/trunk/-/jobs/455155443/artifacts/install/share/doc/yade-ci/html/HighPrecisionReal.html#supported-modules
> >
> >
> >
> > --
> > Janek Kozicki, PhD. DSc. Arch. Assoc. Prof.
> > Gdańsk University of Technology
> > Faculty of Applied Physics and Mathematics
> > Department of Theoretical Physics and Quantum Information
> > --
> > http://yade-dem.org/
> > http://pg.edu.pl/jkozicki (click English flag on top right)
> > ___
> > Mailing list: https://launchpad.net/~yade-dev
> > Post to : yade-dev@lists.launchpad.net
> > Unsubscribe : https://launchpad.net/~yade-dev
> > More help   : https://help.launchpad.net/ListHelp
> >
> 
> 
> -- 
> -- 
> ___
> Bruno Chareyre
> Associate Professor
> ENSE³ - Grenoble INP
> Lab. 3SR
> BP 53
> 38041 Grenoble cedex 9
> Tél : +33 4 56 52 86 21
> 
> 
> Email too brief?
> Here's why: email charter
> 


-- 
--
Janek Kozicki, PhD. DSc. Arch. Assoc. Prof.
Gdańsk University of Technology
Faculty of Applied Physics and Mathematics
Department of Theoretical Physics and Quantum Information
--
http://yade-dem.org/
http://pg.edu.pl/jkozicki (click English flag on top right)

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Re: [Yade-dev] Do we want low precision float in the gitlab CI pipeline?

2020-03-01 Thread Bruno Chareyre 
(sorry for previous empty message)
Hi,
I don't think DEM can realistically work with floats. If 100 particles in a
row are elongated by 0.01%, the relative displacement between the 99th and
100th particles is 1e-6 times the positions. With single precision it would
already produce substantial numerical noise in terms of contact force.
I mentioned single precision in relation with solving linear systems with
cholmod, and that part does not support HP.
I think we can skip the float pipeline. :)
Cheers
Bruno



On Sun, 1 Mar 2020 at 16:24, Janek Kozicki (yade) 
wrote:

> Hi,
>
> The high precision tests are now running in the gitlab pipeline. And
> we can be sure that `double` are not getting by accident into master.
> (except for the modules which are not supported by HP right now [1],
> in there some `double` could sneak in)
>
> This work also makes low-precision possible. I didn't add this to the
> pipeline, thinking it's not of much use. In some comment Bruno
> mentioned that some people want to use float in the GPUs to get the
> results faster. (Whether these results are correct is a topic for a
> different discussion :)
>
> I could prepare a merge request that adds float to the pipeline,
> because it is compiling (so it works) but it is not passing the tests.
>
> The disadvantage is that in many test scripts an exception will have
> to be written using following distinction:
>if (yade.config.highPrecisionDecimalPlaces < 7):
>
> That's because some of the tests produce different results when float
> is used, which is not a surprise ;)
>
> Currently yade --check has following failures on float:
>
> 7  checks are failed
>   checkColliderConstantness.py
>   checkViscElEng.py
>   checkPotentialParticles.py
>   checkColliderCorrectness.py
>   checkJCFpm.py
>   checkWirePM.py
>   checkCapillaryModels.py
>
> And yade --test also has similar errors due to only 6 available
> decimal places. The log is longer, so I attach it.
>
> And most of these failures are because the results are compared with
> 1e-8 precision, while float maximally can offer 6 decimal places.
>
> best regards
> Janek
>
>
> [1]
> https://yade-dev.gitlab.io/-/trunk/-/jobs/455155443/artifacts/install/share/doc/yade-ci/html/HighPrecisionReal.html#supported-modules
>
>
>
> --
> Janek Kozicki, PhD. DSc. Arch. Assoc. Prof.
> Gdańsk University of Technology
> Faculty of Applied Physics and Mathematics
> Department of Theoretical Physics and Quantum Information
> --
> http://yade-dem.org/
> http://pg.edu.pl/jkozicki (click English flag on top right)
> ___
> Mailing list: https://launchpad.net/~yade-dev
> Post to : yade-dev@lists.launchpad.net
> Unsubscribe : https://launchpad.net/~yade-dev
> More help   : https://help.launchpad.net/ListHelp
>


-- 
-- 
___
Bruno Chareyre
Associate Professor
ENSE³ - Grenoble INP
Lab. 3SR
BP 53
38041 Grenoble cedex 9
Tél : +33 4 56 52 86 21


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Here's why: email charter

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Re: [Yade-dev] Do we want low precision float in the gitlab CI pipeline?

2020-03-01 Thread Bruno Chareyre 
Hi,
I don't think DEM can in gener

On Sun, 1 Mar 2020 at 16:24, Janek Kozicki (yade) 
wrote:

> Hi,
>
> The high precision tests are now running in the gitlab pipeline. And
> we can be sure that `double` are not getting by accident into master.
> (except for the modules which are not supported by HP right now [1],
> in there some `double` could sneak in)
>
> This work also makes low-precision possible. I didn't add this to the
> pipeline, thinking it's not of much use. In some comment Bruno
> mentioned that some people want to use float in the GPUs to get the
> results faster. (Whether these results are correct is a topic for a
> different discussion :)
>
> I could prepare a merge request that adds float to the pipeline,
> because it is compiling (so it works) but it is not passing the tests.
>
> The disadvantage is that in many test scripts an exception will have
> to be written using following distinction:
>if (yade.config.highPrecisionDecimalPlaces < 7):
>
> That's because some of the tests produce different results when float
> is used, which is not a surprise ;)
>
> Currently yade --check has following failures on float:
>
> 7  checks are failed
>   checkColliderConstantness.py
>   checkViscElEng.py
>   checkPotentialParticles.py
>   checkColliderCorrectness.py
>   checkJCFpm.py
>   checkWirePM.py
>   checkCapillaryModels.py
>
> And yade --test also has similar errors due to only 6 available
> decimal places. The log is longer, so I attach it.
>
> And most of these failures are because the results are compared with
> 1e-8 precision, while float maximally can offer 6 decimal places.
>
> best regards
> Janek
>
>
> [1]
> https://yade-dev.gitlab.io/-/trunk/-/jobs/455155443/artifacts/install/share/doc/yade-ci/html/HighPrecisionReal.html#supported-modules
>
>
>
> --
> Janek Kozicki, PhD. DSc. Arch. Assoc. Prof.
> Gdańsk University of Technology
> Faculty of Applied Physics and Mathematics
> Department of Theoretical Physics and Quantum Information
> --
> http://yade-dem.org/
> http://pg.edu.pl/jkozicki (click English flag on top right)
> ___
> Mailing list: https://launchpad.net/~yade-dev
> Post to : yade-dev@lists.launchpad.net
> Unsubscribe : https://launchpad.net/~yade-dev
> More help   : https://help.launchpad.net/ListHelp
>


-- 
-- 
___
Bruno Chareyre
Associate Professor
ENSE³ - Grenoble INP
Lab. 3SR
BP 53
38041 Grenoble cedex 9
Tél : +33 4 56 52 86 21


Email too brief?
Here's why: email charter

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