Controlling the Optimization Loops with Stopping Criteria

One topology optimization loop consists of a sequence of one flow analysis followed by one adjoint analysis. The number of iterations of each flow solution and adjoint solution per loop, and the overall number of loops are controlled by individual stopping criteria.

To obtain the steady-state solution of flow variables, you specify a value of 300 iterations initially, then you reduce the number of iterations to 100. For the adjoint solution of the pressure drop objective, you set the number of iterations to 100. This low number of iterations is sufficient as you do not want to achieve full convergence every time, but a solution that is moving in the right direction. For this tutorial, the total number of optimization loops is set to 300.

To control the optimization loops:
  1. Create a stopping criterion for the flow solution:
    1. Right-click the Solvers > Steady > Stopping Criteria node and select New Criterion > Fixed Steps.
    2. Select the Stopping Criteria > Fixed Steps node and set Fixed Steps to ${PrimalIterations}.
  2. Create a stopping criterion for the adjoint solution:
    1. Right-click the Solvers > Adjoint > Solvers > Adjoint Steady > Stopping Criteria node and select New Criterion > Fixed Steps.
    2. Select the Stopping Criteria > Fixed Steps node and set Fixed Steps to 100.
  3. Create an overall stopping criterion:
    1. Right-click the Stopping Criteria node and select New Monitor Criterion.
    2. In the Select Monitor dialog, select Optimization Iteration Monitor.
    3. Edit the Optimization Iteration Monitor Criterion node and set the following properties:
      NodePropertySetting
      Optimization Iteration Monitor CriterionCriterion OptionMaximum
      Maximum LimitMaximum Value300
  4. Select the Stopping Criteria > Maximum Steps node and set Enabled to Deactivated.
  5. Save the simulation.