{"id":455696,"date":"2026-04-02T21:55:00","date_gmt":"2026-04-02T21:55:00","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/em_control_magnet-syntax-issues\/"},"modified":"2026-04-02T21:55:00","modified_gmt":"2026-04-02T21:55:00","slug":"em_control_magnet-syntax-issues","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/em_control_magnet-syntax-issues\/","title":{"rendered":"EM_CONTROL_MAGNET syntax issues"},"content":{"rendered":"

<p>I recently noticed something I didn’t understand with the EM_CONTROL_MAGNET keyword. On page 385 of the keyword manual (https:\/\/lsdyna.ansys.com\/wp-content\/uploads\/2025\/04\/LS-DYNA_Manual_Vol_III_R16.pdf<\/a>) it mentions there are two inputs, both mcomp to turn on the keyword, and ncycm to set the number of cycles. So it would be written like this:<br>*EM_CONTROL_MAGNET<br>$# mcomp ncycm<br>1 100<br>However, when I use lsprepost to make a keyword file and include the EM_CONTROL_MAGNET keyword, there is no ncycm command, only the mcomp, and it is automatically written as:<br>*EM_CONTROL_MAGNET<br>$# mcomp<br>1<\/p><p> <\/p><p>Moreover, with the syntax written by LSPP, the simulation will crash stating “forrtl: severe (164): Program Exception – integer divide by zero” after assembling Fem-Bem matricies, and building P mat, Q mat, and W mat through 100 percent.  This may be a problem with the syntax, or maybe the rebuilding of magnetic vector of a deforming magnet happens too often and there is a threshold somewhere between NCYCM being undefined and 100 that allows the simulation to complete.  If it helps, here is the EM chunk of my .k file<br><br>*EM_PERMANENT_MAGNET<br>$#      id       pid     mtype     north     south        hc<br>         1         1         1         2         1     21033<br>*EM_CONTROL<br>$#   emsol     numls         –   dimtype    nperio         –   ncylfem   ncylbem<br>         1       100                   0         0                   1         1<br>*EM_CONTROL_MAGNET<br>$#   mcomp<br>         1<br>*EM_CONTROL_TIMESTEP<br>$#  tstype    dtcons      lcid    factor     tsmin     tsmas     rlcsf    mecats<br>         3       0.0         0       1.0    1.0E-4      0.25        25         0<br>*EM_CONTROL_COUPLING<br>$#   thcpl     smcpl    thlcid    smlcid   thcplfl   smcplfl<br>         1         2         0         0         0         0<br>*EM_SOLVER_FEMBEM_MONOLITHIC<br>$#   mtype     stype    abstol    reltol     maxit<br>         0         1    1.0E-6    1.0E-4       100<br>*EM_MAT_002<br>$#     mid     mtype     sigma     eosid     murel     eosmu    deatht<br>         1         4       0.0         0       1.1         0    1.0E28<br>*EM_EXTERNAL_FIELD<br>$# fieldid     ftype      fdef     lcidx     lcidy     lcidz<br>         1         1         1         4         2         4<\/p><\/p>\n","protected":false},"template":"","class_list":["post-455696","topic","type-topic","status-publish","hentry","topic-tag-ansys-ls-dyna-1","topic-tag-ls_dyna-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t