[petsc-users] Question about Pseudo Time Stepping

[Aldo Bonfiglioli]

Hi there,

I am using -ts_type pseudo to find steady solutions of the Euler/NS PDEs.

It looks like FormRHSFunction is called twice with the exactly same 
value of the dependent variable (u)

before invoking TSRHSJacobianFn and then solving the linear system with 
KSP (u is then updated)

> 1 TS dt 0.141197 time 0.141197
> Calling FormRHSFunction; ||u|| =    60.489405479528003 
>        463.15635675129079        62.813532026019146 
>        5.9789502719351155
> Calling FormRHSFunction; ||u|| =    60.489405479528003 
>        463.1563567512907962.8135320260191465.9789502719351155
> Calling TSRHSJacobianFn with ||u|| =    60.489405479528003 
>        463.15635675129079        62.813532026019146 
>        5.9789502719351155
>      Linear solve converged due to CONVERGED_RTOL iterations 9
> Calling FormRHSFunction; ||u|| = 
>    60.489405476878737463.1563567560218662.8135320316169655.9789502710519811
> 2 TS dt 0.155917 time 0.297115
> Calling FormRHSFunction; ||u|| = 
>    60.489405476878737463.1563567560218662.8135320316169655.9789502710519811
> Calling FormRHSFunction; ||u|| = 
>    60.489405476878737463.1563567560218662.8135320316169655.9789502710519811
> Calling TSRHSJacobianFn with ||u|| = 
>    60.489405476878737463.1563567560218662.8135320316169655.9789502710519811
>
Why is it so? Am I possibly misusing (or missing) some options?

My .petscrc file is attached.

Thank you,

Aldo

-- 
Dr. Aldo Bonfiglioli
Associate professor of Fluid Mechanics
Dipartimento di Ingegneria
Universita' della Basilicata
V.le dell'Ateneo Lucano, 10 85100 Potenza ITALY
tel:+39.0971.205203 fax:+39.0971.205215
web:https://urldefense.us/v3/__http://docenti.unibas.it/site/home/docente.html?m=002423__;!!G_uCfscf7eWS!ci_aySHdF2Qx_B-37IOzELFDtcQRthJ2NItK-JNbfXB0M2_21B_z97WIfjxZUyKCVRRhd1mzL6b-rnCed_i8LLA56JvFdz7JBrw$ 
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-dm_plex_dim 2
-dm_plex_filename /home/abonfi/grids/2D/aerofoils/naca0012/euler/gmsh/naca0012.msh
#-dm_plex_filename /home/abonfi/grids/2D/aerofoils/naca0012/euler/gmsh/mesh.h5
-testcase 3
##-dm_view
##-dm_plex_view_labels "marker"
##-dm_plex_view_labels "Face Sets"
-freestream_Mach_number .5
-flow_angles 1.,0.,0.
-dm_mat_type baij
##-Reynolds 1.e39
-colors 4,5,-1,-1,-1,-1
-dm_plex_simplex true
-dm_plex_interpolate 
-dm_plex_check_all
-petscpartitioner_view
##-dm_petscsection_view
##-ts_dt 100.
-ts_max_steps 100
-ts_type pseudo
-pc_factor_mat_ordering_type rcm
-pc_factor_reuse_ordering
-ksp_converged_reason
-options_left
##-ksp_view