Help!Numerical Error:IterSolver Iterations:too many iterations were needed!

Clearly defined bug reports and their fixes
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jeffjoy
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Help!Numerical Error:IterSolver Iterations:too many iterations were needed!

Post by jeffjoy »

The procedure can run before,but recently,I run the procedure in a new machine, it doesn't work,errors!
Who knows?please!Error !too many iterations were needed ! in the navier-Stokes equations!

Code: Select all

Solver 4
  Equation = "Navier-Stokes"
  
  Stabilization Method = String Stabilized
  Flow Model = Stokes

  Exported Variable 1 = -dofs 1 "dSdt" 
  Exported Variable 2 = -dofs 1 "dS" 
  Exported Variable 3 = -dofs 1 "ZbDEM"
  Exported Variable 4 = -dofs 1 "ZsDEM"

  Linear System Solver = Iterative      
  Linear System Iterative Method = BICGStab
   
  Linear System Preconditioning = ILU0
  Linear System Convergence Tolerance = Real 1.0e-4 !8
  Linear System Max Iterations = 500
  Linear System Residual Output = 500
  Linear System Abort Not Converged = True 

  Nonlinear System Max Iterations = 50
  Nonlinear System Convergence Tolerance  = 1.0e-3 !5
  Nonlinear System Newton After Iterations = 5 
  Nonlinear System Newton After Tolerance = 1.0e-02
  Nonlinear System Relaxation Factor = 1.00

  Steady State Convergence Tolerance = Real 1.0e-3
End
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raback
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Re: Help!Numerical Error:IterSolver Iterations:too many iterations were needed!

Post by raback »

Hi, This is not a bug as it clearly writes what the issue is. Yes, it is undesired but divergence with itertative solvers does happen. -Peter
jeffjoy
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Joined: 10 Nov 2020, 04:01
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Re: Help!Numerical Error:IterSolver Iterations:too many iterations were needed!

Post by jeffjoy »

raback wrote: 16 Nov 2021, 02:47 Hi, This is not a bug as it clearly writes what the issue is. Yes, it is undesired but divergence with itertative solvers does happen. -Peter
How should we do to deal with it?
kevinarden
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Re: Help!Numerical Error:IterSolver Iterations:too many iterations were needed!

Post by kevinarden »

You could try increasing this

Linear System Max Iterations = 500
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