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fix move/surf command

fix move/surf/kk command


fix ID move/surf groupID Nevery Nlarge args ... 


fix 1 move/surf all 100 1000 trans 1 0 0
fix 1 move/surf partial 100 10000 rotate 360 0 0 1 5 5 0 connect yes
fix 1 move/surf object2 100 50000 rotate 360 0 0 1 5 5 0 


This command performs on-the-fly movement of all the surface elements in the specfied group via one of several styles. See the group surf command for info on how surface elements can be assigned to surface groups. Surface element moves can also be performed before or between simulations by using the move_surf command.

Moving surfaces during a simulation run can be useful if you want to to track transient changes in a flow while some attribute of the surface elements change, e.g. the separation between two spheres.

All of the command arguments which appear after Nlarge, which determine how surface elements move, are exactly the same as for the move_surf command, starting with its style argument. This includes optional keywords it defines. See its doc page for details.

Nevery specifies how often surface elements are moved incrementally along the path towards their final position. The current timestep must be a multiple of Nevery.

Nlarge must be a multiple of Nevery and specifies how long it will take the surface elements to move to their final position.

Thus if Nlarge = 100*Nevery, each surface elements will move 1/100 of its total distance every Nevery steps.

The same rules that the move_surf command follows for particle deletion after surface elements move, are followed by this command as well. The criteria are applied after every incremental move. This is to prevent particles from ending up inside surface objects.

Likewise, the connect option of the move_surf command should be used in the same manner by this command if you need to insure that moving only some elements of an object do not result in a non-watertight surface grid.

Restart, output info:

No information about this fix is written to binary restart files. No global or per-particle or per-grid quantities are stored by this fix for access by various output commands.

Styles with a kk suffix are functionally the same as the corresponding style without the suffix. They have been optimized to run faster, depending on your available hardware, as discussed in the Accelerating SPARTA section of the manual. The accelerated styles take the same arguments and should produce the same results, except for different random number, round-off and precision issues.

These accelerated styles are part of the KOKKOS package. They are only enabled if SPARTA was built with that package. See the Making SPARTA section for more info.

You can specify the accelerated styles explicitly in your input script by including their suffix, or you can use the -suffix command-line switch when you invoke SPARTA, or you can use the suffix command in your input script.

See the Accelerating SPARTA section of the manual for more instructions on how to use the accelerated styles effectively.


An error will be generated if any surface element vertex is moved outside the simulation box.

Related commands:

read_surf, move_surf, remove_surf

Default: none