yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxxxxxx>]

It's all fine provided that you keep it backward-compatible. Else it's
worst than the initial pb in my view.
Cheers
Bruno


Le mer. 29 avr. 2020 09:37, Jerome Duriez <jerome.duriez@xxxxxxxx> a écrit :

> Thanks for feedback, what about just a change in name: gravWork ->
> gravPotential ?
>
> There would be no more doubts whether it is work by gravity or work
> against gravity ; and decrease of that quantity during a fall would seem
> more logical to me (and others ?)
>
> I agree otherwise with your general remarks about O.energy, but since
> it's there (we won't remove it anyway, will we ?) I think it could be
> worth to make such a small improvement.
>
> Jérôme
>
>
> ------
> Chargé de Recherche / Research Associate
> Inrae, RECOVER
> 3275 route Cezanne – CS 40061 13182 Aix-en-Provence Cedex 5 FRANCE
> +33 (0)4 42 66 99 21
>
> https://www6.paca.inrae.fr/recover/membres-du-laboratoire/pages-personnelles/jerome-duriez
>
> On 28/04/2020 16:27, Bruno Chareyre wrote:
> > Hi Jérôme,
> > I feel like it is a question of perspective, and undecidable overall.
> > Is it work by gravity or work against gravity? You can find the two
> > meanings easily. It's still a work in both cases.
> >
> > OTOH it seems these energies are underdocumented overall. I did not find
> > a list of available energies anywhere in the doc.
> > I must say trackEnergy=True is slow. It computes many un-needed things
> > (gravitational work is a good example, why should we increment
> > G-=g*vel*dt at every iteration while we can get at any point in time
> > -g*pos? same issue with elastic work).
> > In current design I would not recommend it although it is elegant and
> > handy for quick tests.
> > Cheers
> > Bruno
> > So
> >
> > Bruno
> >
> > On Mon, 20 Apr 2020 at 16:13, Jerome Duriez <jerome.duriez@xxxxxxxx
> > <mailto:jerome.duriez@xxxxxxxx>> wrote:
> >
> >     I now think the most logical would be to keep this expression with a
> >     minus sign [*], but rename 'gravWork' into 'gravPotential' (like we
> >     have
> >     'elastPotential').
> >
> >     It would reconcile for me the name with the coded expression, and be
> >     more logical with the existence of O.energy.total() function (which
> >     sums
> >     all terms in O.energy and certainly is expected to be constant)
> >
> >
> >     Thoughts ?
> >
> >     [*]
> >
> https://gitlab.com/yade-dev/trunk/-/blob/master/pkg/dem/NewtonIntegrator.cpp#L85
> >
> >     ------
> >     Chargé de Recherche / Research Associate
> >     Inrae, RECOVER
> >     3275 route Cezanne – CS 40061 13182 Aix-en-Provence Cedex 5 FRANCE
> >     +33 (0)4 42 66 99 21
> >
> https://www6.paca.inrae.fr/recover/membres-du-laboratoire/pages-personnelles/jerome-duriez
> >
> >     On 20/04/2020 10:25, Jerome Duriez wrote:
> >      > Hi,
> >      >
> >      > Is there a consensus (outside myself) for the extra minus sign in
> >      > O.energy['gravWork'], computed in NewtonIntegrator at [*].
> >      >
> >      > It seems that code line was initially introduced by Vaclav in
> >      > GravityEngine in commit [**] (and made finally its way into
> >      > NewtonIntegrator).
> >      >
> >      > As far as I'm concerned, I can not make sense of the comment
> >     justifying
> >      > that sign, just above [*], neither of a consequent negative power
> of
> >      > weight during some free fall.
> >      >
> >      >
> >      > Jérôme
> >      >
> >      >
> >      > [*]
> >      >
> >
> https://gitlab.com/yade-dev/trunk/-/blob/master/pkg/dem/NewtonIntegrator.cpp#L85
> >
> >      >
> >      >
> >      > [**]
> >      >
> >
> https://gitlab.com/yade-dev/trunk/-/commit/d41480acf2ad616268c9ed562b625952c87c98a5
> ,
> >
> >      > see also corresponding file from that time at
> >      >
> >
> https://gitlab.com/yade-dev/trunk/-/blob/d41480acf2ad616268c9ed562b625952c87c98a5/pkg/common/GravityEngines.cpp#L33
> >
> >      >
> >      > ------
> >      > Chargé de Recherche / Research Associate
> >      > Inrae, RECOVER
> >      > 3275 route Cezanne – CS 40061 13182 Aix-en-Provence Cedex 5 FRANCE
> >      > +33 (0)4 42 66 99 21
> >      >
> >
> https://www6.paca.inrae.fr/recover/membres-du-laboratoire/pages-personnelles/jerome-duriez
> >
> >      >
> >
> >     _______________________________________________
> >     Mailing list: https://launchpad.net/~yade-dev
> >     Post to     : yade-dev@xxxxxxxxxxxxxxxxxxx
> >     <mailto:yade-dev@xxxxxxxxxxxxxxxxxxx>
> >     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
> > <https://marcuselliott.co.uk/wp-content/uploads/2017/04/emailCharter.jpg
> >
>
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-dev
> Post to     : yade-dev@xxxxxxxxxxxxxxxxxxx
> Unsubscribe : https://launchpad.net/~yade-dev
> More help   : https://help.launchpad.net/ListHelp
>