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Optimization methods

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I try topology optimization, and its working. I wanted to check difference in algorithms, but when i want to use f.ex. SQP, message appears:

   *** ERROR # 1870 ***
  Topology and free-sizing optimization are not available when the
  MFD, SQP or BIGOPT optimization methods are selected on the DOPTPRM
  OPTMETH card. The DUAL optimizer must be used.


It is weird, because MFD or SQP can (theoretically) be use for topology optimization. Maybe there are different parameters to change?


Best regards


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Optimization Algoritms
If the default settings fail to converge to a feasible solution, a different optimization algorithm can help
Use DOPTPRM, OPTMETH to change the default
For topology, free-size and topography optimization

  • DUAL 
  • DUAL2 (default) – improved and more stable

For size and shape

  • MFD (default)
  • SQP (default if equality constraints are present)

Note:DUAL2 appears to be more stable than DUAL. Solution stability has been improved, reducing probability of failure in converging to a solution. For legacy reasons, the default CONLIN version remains DUAL. Use DUAL2 if Topology, Free-Size, or Topography optimization fails to converge

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