Warmstart

[jacopenji]

A warmstart flag is present in the input file. Has this feature been implemented? @RShaw026

[PhilipOesterlePekrun]

Yes, it has been implemented and should work.

[jacopenji]

Hi Philip, thanks for the fast reply and for the help in improving the code.
May I also ask you how the input file should be modified to solve an incremental problem exploiting the warmstart?
Thanks!

[PhilipOesterlePekrun]

@jacopenji You would just set WarmStartingFlag: true in the .yaml file. For example

mirco_input:
  WarmStartingFlag: true
  RandomTopologyFlag: true
  RandomSeedFlag: false
  MaxIteration: 100
  PressureGreenFunFlag: true
  parameters:
    material_parameters:
      E1: 1.0
      nu1: 0.3
      E2: 1.0
      nu2: 0.3
    geometrical_parameters:
      LateralLength: 1000.0
      Resolution: 7
      HurstExponent: 0.7
      InitialTopologyStdDeviation: 20.0
      Delta: 10.0
      Tolerance: 0.01

I have sometimes seen improvements in the time to solution of 4x by using warmstart, so it is indeed very useful.

[mayrmt]

@jacopenji are you looking for a "load stepping scheme", i.e. imposing a final value of the far field displacement subdivided into smaller increments?

[RShaw026]

@jacopenji Currently we can solve for one far-field displacement Delta at a time in an input file. Warm start is used only in the correction process. Currently, there is no way to define multiple load steps in one input file and no provision to use the active set of the previous load step in the next time step. Are you looking for a way to define multiple load steps in an input file?

[jacopenji]

Ok, yes, that is what I was interested in. Thanks all for the clarification.