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[Bruno Chareyre <1400075@xxxxxxxxxxxxxxxxxx>]

It seems to me that:
1/ a robust (velocity-consistent) implementation would need much more than a simple bugfix
2/ assigning velocity is the right way to control motion according to the documentation [1]
Therefore, I would suggest to simply remove addMove from sources.

Do you guys have a realistic example of something that can't be achieved without addMove?
As mentionned in #2, assigning velocity means that the displacement per iteration depends on the timestep but isn't it what we want? I mean, imposing a constant displacement of a body per timestep implies that the velocity of the said body is changing all the time (with a changing dt). A physical quantity depending on a numerical detail is an odd feature.

Further, if someone really wants to addMove() and doesn't care about velocity consictency, it could be simply:
b.state.pos += move #in a pyRunner, typically

[1] https://yade-dem.org/doc/user.html#imposed-velocity


@Janek
>you will see that addMove() isn't used anywhere except for the file ./examples/test/force-move.py

This grep output is typical for such function (supposed to be used
through python wrapper mainly), i.e. implementation in the source code +
one example script. It doesn't tell really if the function is used or
not (by yade users), and if it is used it can still have nasty side
effects.

@Vaclav
>I would have to remember hard what was the reason to introduce it

Maybe an intermediate state of the tensile tests, where groups of
particles had to be moved as rigid blocks - now done with constant
velocity but maybe with constant disp/iter previously?

Bruno

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https://bugs.launchpad.net/bugs/1400075

Title:
  O.forces.addMove does not work

Status in Yet Another Dynamic Engine:
  New

Bug description:
  Hi,

  I tried O.forces.addMove to apply displacement to a particle, but the
  method seems not to work..

  b = sphere((0,0,0),1)
  O.bodies.append(b)
  O.forces.addMove(0,(1,0,0))
  print b.state.pos # (0,0,0)
  O.step()
  print b.state.pos # is (0,0,0) again...

  Is this behavior ok, do I do something wrong or is it a bug?

  I use Ubuntu 14.04 and yade  2014-11-08.git-d693417

  Thanks
  Jan

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