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Hello,</div>
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I want to solve PF solidification+Navier stokes using Finite different method, and I have a strange problem. My code runs fine for some system sizes and fails for some of the system sizes. When I run with the following options:</div>
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<span style="background-color: rgb(0, 255, 0);">mpirun -np 2 ./one.out -ts_monitor -snes_fd_color -ts_max_snes_failures -1 -ts_type bdf -ts_bdf_adapt -pc_type bjacobi -snes_linesearch_type l2 -snes_type ksponly -ksp_type gmres -ksp_gmres_restart 1001 -sub_pc_type
ilu -sub_ksp_type preonly -snes_monitor -ksp_monitor -snes_linesearch_monitor -ksp_monitor_true_residual -ksp_converged_reason -log_view</span></div>
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<span style="background-color: rgb(255, 255, 128);"><br>
</span></div>
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<span style="background-color: rgb(255, 255, 255); color: rgb(12, 136, 42);"> 0 SNES Function norm 1.465357113711e+01
</span><span style="background-color: rgb(255, 255, 128);">
<div><span style="color: rgb(12, 136, 42);"> 0 SNES Function norm 1.465357113711e+01
</span></div>
<div><span style="color: rgb(12, 136, 42);"> Linear solve did not converge due to DIVERGED_PC_FAILED iterations 0</span></div>
<div><span style="color: rgb(12, 136, 42);"> PC_FAILED due to SUBPC_ERROR
</span></div>
<div><span style="color: rgb(12, 136, 42);"> Linear solve did not converge due to DIVERGED_PC_FAILED iterations 0</span></div>
<div><span style="color: rgb(12, 136, 42);"> PC_FAILED due to SUBPC_ERROR
</span></div>
<div><span style="color: rgb(12, 136, 42);"> 0 SNES Function norm 1.465357113711e+01
</span></div>
<div><span style="color: rgb(12, 136, 42);"> 0 SNES Function norm 1.465357113711e+01
</span></div>
<div><span style="color: rgb(12, 136, 42);"> Linear solve did not converge due to DIVERGED_PC_FAILED iterations 0</span></div>
<div><span style="color: rgb(12, 136, 42);"> PC_FAILED due to SUBPC_ERROR
</span></div>
<div><span style="color: rgb(12, 136, 42);"> Linear solve did not converge due to DIVERGED_PC_FAILED iterations 0</span></div>
<div><span style="color: rgb(12, 136, 42);"> PC_FAILED due to SUBPC_ERROR
</span></div>
<div><span style="color: rgb(12, 136, 42);"> 0 SNES Function norm 1.465357113711e+01
</span></div>
<div><span style="color: rgb(12, 136, 42);"> 0 SNES Function norm 1.465357113711e+01
</span></div>
<div><span style="color: rgb(12, 136, 42);">^C Linear solve did not converge due to DIVERGED_PC_FAILED iterations 0</span></div>
<div><span style="color: rgb(12, 136, 42);"> PC_FAILED due to SUBPC_ERROR
</span></div>
<div><span style="color: rgb(12, 136, 42);"> 0 SNES Function norm 1.465357113711e+01
</span></div>
<div><span style="color: rgb(12, 136, 42);"> Linear solve did not converge due to DIVERGED_PC_FAILED iterations 0</span></div>
<div><span style="color: rgb(12, 136, 42);"> PC_FAILED due to SUBPC_ERROR
</span></div>
<div><span style="color: rgb(12, 136, 42);"> 0 SNES Function norm 1.465357113711e+01</span>
</div>
</span></div>
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<br>
</div>
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<span style="background-color: rgb(255, 128, 255);">Even setting pc_type to LU does not solve the problem.</span></div>
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<span style="color: rgb(237, 92, 87);">0 TS dt 0.0001 time 0.</span>
<div><span style="color: rgb(237, 92, 87);">copy!</span></div>
<div><span style="color: rgb(237, 92, 87);">copy!</span></div>
<div><span style="color: rgb(237, 92, 87);">Write output at step= 0!</span></div>
<div><span style="color: rgb(237, 92, 87);">Write output at step= 0!</span></div>
<div><span style="color: rgb(237, 92, 87);"> 0 SNES Function norm 1.465357113711e+01
</span></div>
<div><span style="color: rgb(237, 92, 87);"> 0 SNES Function norm 1.465357113711e+01
</span></div>
<div><span style="color: rgb(237, 92, 87);"> Linear solve did not converge due to DIVERGED_PC_FAILED iterations 0</span></div>
<div><span style="color: rgb(237, 92, 87);"> PC_FAILED due to FACTOR_NUMERIC_ZEROPIVOT
</span></div>
<div><span style="color: rgb(237, 92, 87);"> Linear solve did not converge due to DIVERGED_PC_FAILED iterations 0</span></div>
<span style="color: rgb(237, 92, 87);"> PC_FAILED due to FACTOR_NUMERIC_ZEROPIVOT</span></div>
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<br>
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I guess the problem is that in mass conservation I used forward discretization for u (velocity in x) and for the moment in x , I used forward discretization for p (pressure) to ensure non-zero terms on the diagonal of matrix. I tried to run it with valgrind
but it did not output anything. <br>
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<br>
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Does anyone have suggestions on how to solve this issue? <br>
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Best,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Sepideh<br>
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