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1

Can someone please answer Lili’s question. I also can not figure it out.

Regards,

Mojib

Hi All,

May I ask a question following this thread regarding the meaning of the
"args" of keywords "*pos*" and "*vel*" in "fix wall/piston command?"  The
doc says that

*"pos* args = z
    z = z coordinate at which the piston begins (distance units)
  *vel* args = vz
    vz = final velocity of the piston (velocity units)"

which seems: pos needs only one argument z, and vel needs only one
argument vz (the z component of the piston).

But in the Example part of the doc:  fix walls all wall/piston zlo pos
1.0 0.0 0.0 vel 0.0 0.0 10.0 units box

There are three args for each, what is the meaning of them?

Thank you very much,
Lili
2

That is an error with the doc page. This command requires x, y, and z coordinates for the pos keyword and x, y, and z velocities for the vel keyword. Note the wall can only move in the +z direction, so x and y velocities have no effect at all. The same for x and y for pos keyword - they have no effect. There may be a need to change the source code to match the doc page, since the doc page makes more sense to me.

Ray

3

I changed the code to just use the z and vz values, not x,y.

The doc page is thus correct, except the examples were also
changed to just take a single value.

Steve