Optimization methods

jakub.ziontek
jakub.ziontek Altair Community Member
edited October 2020 in Community Q&A

Hi

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

Jakub  

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Answers

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited October 2019

    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)
    • BIGOPT

    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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