Merge pull request #6235 from jdannberg/failure_cut_timestep_fix

Fix for cut timestep size nonlinear solver strategy

Author: gassmoeller

doc/modules/changes/20250214_jdannberg

@@ -0,0 +1,9 @@
+Fixed: If the nonlinear solver fails in a timestep with mesh
+refinement and "cut timestep size" is selected as the
+Nonlinear solver failure strategy, ASPECT now correctly
+repeats the timestep first before refining the mesh. Before,
+ASPECT would execute refinement/coarsening of the mesh first,
+which could lead to changes of the mesh in each failure
+cycle.
+<br>
+(Juliane Dannberg, 2025/02/14)

source/simulator/core.cc

@@ -2123,17 +2123,17 @@ namespace aspect
             && !parameters.run_postprocessors_on_nonlinear_iterations)
           postprocess ();
 
+        // if the time stepping manager tells us to refine the mesh,
+        // we need to do this before going to the next time step
         if (time_stepping_manager.should_refine_mesh())
           {
             pcout << "Refining the mesh based on the time stepping manager ...\n" << std::endl;
             refine_mesh(max_refinement_level);
           }
-        else
-          maybe_refine_mesh(new_time_step_size, max_refinement_level);
 
         if (time_stepping_manager.should_repeat_time_step())
           {
-            pcout << "Repeating the current time step based on the time stepping manager ..." << std::endl;
+            pcout << "Repeating the current time step based on the time stepping manager ...\n" << std::endl;
 
             if (mesh_deformation)
               mesh_deformation->mesh_displacements = mesh_deformation->old_mesh_displacements;
@@ -2151,6 +2151,9 @@ namespace aspect
             continue; // repeat time step loop
           }
 
+        if (!time_stepping_manager.should_refine_mesh())
+          maybe_refine_mesh(new_time_step_size, max_refinement_level);
+
         // see if we want to write a timing summary
         maybe_write_timing_output();
 

tests/free_surface_timestep_repeat/screen-output

@@ -45,84 +45,81 @@ Number of mesh deformation degrees of freedom: 1,162
    Solving ve_stress_xy system ... 12 iterations.
    Solving Stokes system (GMG)... 46+0 iterations.
 
-Number of active cells: 505 (on 3 levels)
-Number of degrees of freedom: 12,022 (4,356+566+566+2,178+2,178+2,178)
-
-Number of mesh deformation degrees of freedom: 1,132
 Repeating the current time step based on the time stepping manager ...
+
 *** Timestep 1:  t=0.460632 years, dt=0.460632 years
    Solving mesh displacement system... 5 iterations.
    Solving temperature system... 0 iterations.
    Solving ve_stress_xx system ... 12 iterations.
    Solving ve_stress_yy system ... 12 iterations.
    Solving ve_stress_xy system ... 12 iterations.
-   Solving Stokes system (GMG)... 51+0 iterations.
+   Solving Stokes system (GMG)... 47+0 iterations.
 
    Postprocessing:
-     Compositions min/max/mass: -2.36e+05/4.138e+05/3.094e+11 // -4.138e+05/2.36e+05/-3.094e+11 // -9.739e+04/5.046e+05/1.814e+16
+     Compositions min/max/mass: -2.36e+05/4.138e+05/3.097e+11 // -4.138e+05/2.36e+05/-3.097e+11 // -9.736e+04/5.045e+05/1.814e+16
      Temperature min/avg/max:   293 K, 293 K, 293 K
      Topography min/max:        -11.65 m, 4.811 m
      RMS, max velocity:         19.5 m/year, 63.2 m/year
 
-Number of active cells: 499 (on 3 levels)
-Number of degrees of freedom: 11,895 (4,310+560+560+2,155+2,155+2,155)
+Number of active cells: 505 (on 3 levels)
+Number of degrees of freedom: 12,022 (4,356+566+566+2,178+2,178+2,178)
 
-Number of mesh deformation degrees of freedom: 1,120
+Number of mesh deformation degrees of freedom: 1,132
 *** Timestep 2:  t=0.960632 years, dt=0.5 years
    Solving mesh displacement system... 5 iterations.
    Solving temperature system... 0 iterations.
    Solving ve_stress_xx system ... 12 iterations.
    Solving ve_stress_yy system ... 12 iterations.
    Solving ve_stress_xy system ... 11 iterations.
-   Solving Stokes system (GMG)... 54+0 iterations.
+   Solving Stokes system (GMG)... 53+0 iterations.
 
    Postprocessing:
-     Compositions min/max/mass: -2.096e+06/3.187e+06/2.942e+12 // -3.187e+06/2.096e+06/-2.942e+12 // -8.812e+05/4.289e+06/1.333e+17
+     Compositions min/max/mass: -2.095e+06/3.187e+06/-8.572e+11 // -3.187e+06/2.095e+06/8.572e+11 // -8.812e+05/4.289e+06/1.333e+17
      Temperature min/avg/max:   293 K, 293 K, 293 K
      Topography min/max:        -43.31 m, 18.13 m
      RMS, max velocity:         8.63 m/year, 27.4 m/year
 
-Number of active cells: 502 (on 3 levels)
-Number of degrees of freedom: 11,956 (4,332+563+563+2,166+2,166+2,166)
+Number of active cells: 499 (on 3 levels)
+Number of degrees of freedom: 11,895 (4,310+560+560+2,155+2,155+2,155)
 
-Number of mesh deformation degrees of freedom: 1,126
+Number of mesh deformation degrees of freedom: 1,120
 *** Timestep 3:  t=1.46063 years, dt=0.5 years
    Solving mesh displacement system... 5 iterations.
    Solving temperature system... 0 iterations.
    Solving ve_stress_xx system ... 12 iterations.
    Solving ve_stress_yy system ... 12 iterations.
    Solving ve_stress_xy system ... 12 iterations.
-   Solving Stokes system (GMG)... 53+0 iterations.
+   Solving Stokes system (GMG)... 54+0 iterations.
 
    Postprocessing:
-     Compositions min/max/mass: -1.204e+06/1.463e+06/1.36e+13 // -1.463e+06/1.204e+06/-1.36e+13 // -6.296e+05/2.308e+06/5.936e+16
+     Compositions min/max/mass: -1.204e+06/1.463e+06/9.777e+12 // -1.463e+06/1.204e+06/-9.777e+12 // -6.296e+05/2.307e+06/5.939e+16
      Temperature min/avg/max:   293 K, 293 K, 293 K
      Topography min/max:        -29.59 m, 12.04 m
      RMS, max velocity:         7.63 m/year, 24.4 m/year
 
-Number of active cells: 499 (on 3 levels)
-Number of degrees of freedom: 11,895 (4,310+560+560+2,155+2,155+2,155)
+Number of active cells: 502 (on 3 levels)
+Number of degrees of freedom: 11,956 (4,332+563+563+2,166+2,166+2,166)
 
-Number of mesh deformation degrees of freedom: 1,120
-*** Timestep 4:  t=1.97252 years, dt=0.511887 years
+Number of mesh deformation degrees of freedom: 1,126
+*** Timestep 4:  t=1.97242 years, dt=0.511791 years
    Solving mesh displacement system... 5 iterations.
    Solving temperature system... 0 iterations.
    Solving ve_stress_xx system ... 12 iterations.
    Solving ve_stress_yy system ... 12 iterations.
    Solving ve_stress_xy system ... 12 iterations.
-   Solving Stokes system (GMG)... 54+0 iterations.
+   Solving Stokes system (GMG)... 53+0 iterations.
 
    Postprocessing:
-     Compositions min/max/mass: -1.958e+06/2.632e+06/7.548e+12 // -2.632e+06/1.958e+06/-7.548e+12 // -1.046e+06/3.851e+06/1.095e+17
+     Compositions min/max/mass: -1.959e+06/2.632e+06/1.494e+13 // -2.632e+06/1.959e+06/-1.494e+13 // -1.046e+06/3.85e+06/1.095e+17
      Temperature min/avg/max:   293 K, 293 K, 293 K
      Topography min/max:        -42.1 m, 17.48 m
      RMS, max velocity:         3.72 m/year, 11.6 m/year
 
-Number of active cells: 502 (on 3 levels)
-Number of degrees of freedom: 11,956 (4,332+563+563+2,166+2,166+2,166)
+Number of active cells: 499 (on 3 levels)
+Number of degrees of freedom: 11,895 (4,310+560+560+2,155+2,155+2,155)
 
-Number of mesh deformation degrees of freedom: 1,126
-*** Timestep 5:  t=2 years, dt=0.0274814 years
+Number of mesh deformation degrees of freedom: 1,120
+*** Timestep 5:  t=2 years, dt=0.0275774 years
    Solving mesh displacement system... 5 iterations.
    Solving temperature system... 0 iterations.
    Solving ve_stress_xx system ... 10 iterations.
@@ -131,16 +128,16 @@ Number of mesh deformation degrees of freedom: 1,126
    Solving Stokes system (GMG)... 50+0 iterations.
 
    Postprocessing:
-     Compositions min/max/mass: -1.953e+06/2.611e+06/7.161e+12 // -2.611e+06/1.953e+06/-7.161e+12 // -1.049e+06/3.836e+06/1.086e+17
+     Compositions min/max/mass: -1.954e+06/2.611e+06/1.511e+13 // -2.611e+06/1.954e+06/-1.511e+13 // -1.049e+06/3.835e+06/1.086e+17
      Temperature min/avg/max:   293 K, 293 K, 293 K
      Topography min/max:        -41.78 m, 17.33 m
-     RMS, max velocity:         65.5 m/year, 204 m/year
+     RMS, max velocity:         65.2 m/year, 203 m/year
      Writing graphical output:  output-free_surface_timestep_repeat/solution/solution-00001
 
-Number of active cells: 499 (on 3 levels)
-Number of degrees of freedom: 11,895 (4,310+560+560+2,155+2,155+2,155)
+Number of active cells: 502 (on 3 levels)
+Number of degrees of freedom: 11,956 (4,332+563+563+2,166+2,166+2,166)
 
-Number of mesh deformation degrees of freedom: 1,120
+Number of mesh deformation degrees of freedom: 1,126
 Termination requested by criterion: end time
 
 

tests/free_surface_timestep_repeat/statistics

@@ -30,9 +30,9 @@
 # 30: RMS velocity (m/year)
 # 31: Max. velocity (m/year)
 # 32: Visualization file name
-0 0.000000000000e+00 0.000000000000e+00 547 5283 607 7014 0  0  0  0 40 42 42  0.00000000e+00 0.00000000e+00 0.00000000e+00  0.00000000e+00 0.00000000e+00  0.00000000e+00  0.00000000e+00 0.00000000e+00 0.00000000e+00 2.93000000e+02 2.93000000e+02 2.93000000e+02  0.00000000e+00  0.00000000e+00 0.00000000e+00 4.30293501e+00 1.35647074e+01 output-free_surface_timestep_repeat/solution/solution-00000 
-1 4.606320049007e-01 4.606320049007e-01 505 4922 566 6534 0 24 24 24 95 99 99 -2.35990776e+05 4.13757522e+05 3.09411377e+11 -4.13757522e+05 2.35990776e+05 -3.09411377e+11 -9.73936239e+04 5.04577200e+05 1.81434010e+16 2.93000000e+02 2.93000000e+02 2.93000000e+02 -6.17699489e-16 -1.16534250e+01 4.81087884e+00 1.95058152e+01 6.32374792e+01                                                          "" 
-2 9.606320049007e-01 5.000000000000e-01 499 4870 560 6465 0 12 12 11 53 55 55 -2.09566169e+06 3.18669907e+06 2.94173714e+12 -3.18669907e+06 2.09566169e+06 -2.94173714e+12 -8.81213946e+05 4.28852593e+06 1.33287393e+17 2.93000000e+02 2.93000000e+02 2.93000000e+02  0.00000000e+00 -4.33069967e+01 1.81263226e+01 8.63329048e+00 2.74078607e+01                                                          "" 
-3 1.460632004901e+00 5.000000000000e-01 502 4895 563 6498 0 12 12 12 52 54 54 -1.20361490e+06 1.46277555e+06 1.35953400e+13 -1.46277555e+06 1.20361490e+06 -1.35953400e+13 -6.29617426e+05 2.30755820e+06 5.93597106e+16 2.93000000e+02 2.93000000e+02 2.93000000e+02  2.25987618e-16 -2.95874495e+01 1.20362040e+01 7.62819605e+00 2.44127830e+01                                                          "" 
-4 1.972518629830e+00 5.118866249297e-01 499 4870 560 6465 0 12 12 12 53 55 55 -1.95839260e+06 2.63170605e+06 7.54831352e+12 -2.63170605e+06 1.95839260e+06 -7.54831352e+12 -1.04564407e+06 3.85125539e+06 1.09491021e+17 2.93000000e+02 2.93000000e+02 2.93000000e+02 -1.50658412e-17 -4.20977965e+01 1.74799578e+01 3.72450610e+00 1.15928563e+01                                                          "" 
-5 2.000000000000e+00 2.748137016955e-02 502 4895 563 6498 0 10 10 10 49 51 51 -1.95300695e+06 2.61143532e+06 7.16143046e+12 -2.61143532e+06 1.95300695e+06 -7.16143046e+12 -1.04914831e+06 3.83563457e+06 1.08581043e+17 2.93000000e+02 2.93000000e+02 2.93000000e+02 -3.16382665e-16 -4.17788330e+01 1.73314344e+01 6.55142505e+01 2.04138181e+02 output-free_surface_timestep_repeat/solution/solution-00001 
+0 0.000000000000e+00 0.000000000000e+00 547 5283 607 7014 0  0  0  0 40 42 42  0.00000000e+00 0.00000000e+00  0.00000000e+00  0.00000000e+00 0.00000000e+00  0.00000000e+00  0.00000000e+00 0.00000000e+00 0.00000000e+00 2.93000000e+02 2.93000000e+02 2.93000000e+02  0.00000000e+00  0.00000000e+00 0.00000000e+00 4.30293501e+00 1.35647074e+01 output-free_surface_timestep_repeat/solution/solution-00000 
+1 4.606320049007e-01 4.606320049007e-01 520 5055 581 6711 0 24 24 24 91 95 95 -2.35970380e+05 4.13757219e+05  3.09717661e+11 -4.13757219e+05 2.35970380e+05 -3.09717661e+11 -9.73645441e+04 5.04526986e+05 1.81434014e+16 2.93000000e+02 2.93000000e+02 2.93000000e+02 -9.03950472e-17 -1.16534234e+01 4.81092915e+00 1.95058162e+01 6.32372447e+01                                                          "" 
+2 9.606320049007e-01 5.000000000000e-01 505 4922 566 6534 0 12 12 11 52 54 54 -2.09535068e+06 3.18666459e+06 -8.57220878e+11 -3.18666459e+06 2.09535068e+06  8.57220878e+11 -8.81179760e+05 4.28871285e+06 1.33279906e+17 2.93000000e+02 2.93000000e+02 2.93000000e+02  1.20526730e-16 -4.33068823e+01 1.81261689e+01 8.63338662e+00 2.74096791e+01                                                          "" 
+3 1.460632004901e+00 5.000000000000e-01 499 4870 560 6465 0 12 12 12 53 55 55 -1.20354792e+06 1.46262676e+06  9.77736170e+12 -1.46262676e+06 1.20354792e+06 -9.77736170e+12 -6.29632809e+05 2.30748415e+06 5.93930090e+16 2.93000000e+02 2.93000000e+02 2.93000000e+02 -1.05460888e-16 -2.95864265e+01 1.20371251e+01 7.62739115e+00 2.44174175e+01                                                          "" 
+4 1.972422597720e+00 5.117905928193e-01 502 4895 563 6498 0 12 12 12 52 54 54 -1.95901040e+06 2.63180128e+06  1.49396196e+13 -2.63180128e+06 1.95901040e+06 -1.49396196e+13 -1.04559648e+06 3.85043082e+06 1.09480836e+17 2.93000000e+02 2.93000000e+02 2.93000000e+02 -6.02633648e-17 -4.20967760e+01 1.74761044e+01 3.72173130e+00 1.15843521e+01                                                          "" 
+5 2.000000000000e+00 2.757740227997e-02 499 4870 560 6465 0 10 10 10 49 51 51 -1.95361330e+06 2.61147875e+06  1.51065024e+13 -2.61147875e+06 1.95361330e+06 -1.51065024e+13 -1.04911666e+06 3.83476186e+06 1.08581340e+17 2.93000000e+02 2.93000000e+02 2.93000000e+02  1.50658412e-17 -4.17769337e+01 1.73271746e+01 6.52152985e+01 2.03164129e+02 output-free_surface_timestep_repeat/solution/solution-00001 

tests/nonlinear_failure_strategy_cut/screen-output

@@ -49,6 +49,7 @@ Number of degrees of freedom: 9,141 (4,290+561+2,145+2,145)
 WARNING: The nonlinear solver in the current timestep failed to converge.
 Acting according to the parameter 'Nonlinear solver failure strategy'...
 Repeating the current time step based on the time stepping manager ...
+
 *** Timestep 1:  t=6625.49 years, dt=6625.49 years
    Solving temperature system... 11 iterations.
    Skipping porosity composition solve because RHS is zero.

tests/nonlinear_failure_strategy_cut_refinement.prm

@@ -0,0 +1,22 @@
+# Check that nonlinear solver strategy "cut timestep size" works
+# also if we change the mesh in the same time step.
+#
+# Like iterated_advection_and_stokes_residual.prm
+# but we coarsen the mesh after timestep 0 and 1.
+
+include $ASPECT_SOURCE_DIR/tests/iterated_advection_and_stokes_residual.prm
+
+set Nonlinear solver failure strategy = cut timestep size
+set Max nonlinear iterations = 4
+set Dimension = 2
+set End time = 14000
+
+subsection Mesh refinement
+  set Coarsening fraction                      = 1
+  set Refinement fraction                      = 0
+  set Initial adaptive refinement              = 0
+  set Initial global refinement                = 4
+  set Strategy                                 = composition
+  set Time steps between mesh refinement       = 1
+  set Minimum refinement level                 = 2
+end