[petsc-users] SNES convergence issue

Tue May 17 08:13:44 CDT 2011

Gregory E. Fasshauer has a book and set of Matlab routines for meshfree methods http://www.mathworks.com/support/books/book48894.html?category=new   Perhaps you can use those to mimimc the rbf meshfree method you have coded and determine what has gone wrong.

  Barry

On May 17, 2011, at 1:09 AM, Tian(ICT) wrote:

> I am using SNES to solve a superelastic large deformatoin beam problem. The model contains only one brick element.
> I am solving the problem using both a FE and a RBF meshfree approximation. The code flows in the same way and switching between
> the two different approximation is just a change in shape function. The FE method converges well and matched with another code's results.
> However, the rbf meshfree method does not converge. I combed the code and could not find a reason.
> The following is the output. Anyone can give me a hint what is happening.
>  
> c:\pgfem -snes_monitor -ksp_type fgmres -ksp_monitor_true_residual -ksp_gmres_modifiedgramschmidt -ksp_rtol 1e-10 -pc_type none
>  
> atol=1e-050, rtol=1e-008, stol=1e-008, maxit=50, maxf=10000
>   0 SNES Function norm 7.071067597552e-001 
>   0 KSP preconditioned resid norm 7.071067597552e-001 true resid norm 7.071067597552e-001 ||Ae||/||Ax|| 1.000000000000e+000
>   1 KSP preconditioned resid norm 6.487378720919e-001 true resid norm 6.487378720919e-001 ||Ae||/||Ax|| 9.174539249441e-001
>   2 KSP preconditioned resid norm 5.946077657343e-001 true resid norm 5.946077657343e-001 ||Ae||/||Ax|| 8.409023920802e-001
>   3 KSP preconditioned resid norm 5.819067797177e-001 true resid norm 5.819067797177e-001 ||Ae||/||Ax|| 8.229404848557e-001
>   4 KSP preconditioned resid norm 5.782978365298e-001 true resid norm 5.782978365298e-001 ||Ae||/||Ax|| 8.178366682988e-001
>   5 KSP preconditioned resid norm 5.781901258865e-001 true resid norm 5.781901258865e-001 ||Ae||/||Ax|| 8.176843424417e-001
>   6 KSP preconditioned resid norm 5.206124902964e-001 true resid norm 5.206124902965e-001 ||Ae||/||Ax|| 7.362572668330e-001
>   7 KSP preconditioned resid norm 4.698325347773e-001 true resid norm 4.698325347774e-001 ||Ae||/||Ax|| 6.644435628646e-001
>   8 KSP preconditioned resid norm 2.252503531363e-001 true resid norm 2.252503531382e-001 ||Ae||/||Ax|| 3.185521139923e-001
>   9 KSP preconditioned resid norm 6.934719137364e-002 true resid norm 6.934719137322e-002 ||Ae||/||Ax|| 9.807174152489e-002
>  10 KSP preconditioned resid norm 2.116841871461e-003 true resid norm 2.116841872136e-003 ||Ae||/||Ax|| 2.993666575708e-003
>  11 KSP preconditioned resid norm 2.248666383380e-005 true resid norm 2.248666456589e-005 ||Ae||/||Ax|| 3.180094696545e-005
>  12 KSP preconditioned resid norm 1.982194861438e-005 true resid norm 1.982195167981e-005 ||Ae||/||Ax|| 2.803247374791e-005
>  13 KSP preconditioned resid norm 7.277668728205e-007 true resid norm 7.277725200859e-007 ||Ae||/||Ax|| 1.029225799422e-006
>  14 KSP preconditioned resid norm 5.491308415661e-007 true resid norm 5.491254698377e-007 ||Ae||/||Ax|| 7.765807104259e-007
>  15 KSP preconditioned resid norm 1.986082449735e-008 true resid norm 1.986464500270e-008 ||Ae||/||Ax|| 2.809285122600e-008
>  16 KSP preconditioned resid norm 2.868546981451e-012 true resid norm 2.473921585844e-011 ||Ae||/||Ax|| 3.498653564987e-011
>   1 SNES Function norm 6.961586744390e-001 
>   0 KSP preconditioned resid norm 6.961586744390e-001 true resid norm 6.961586744390e-001 ||Ae||/||Ax|| 1.000000000000e+000
>   1 KSP preconditioned resid norm 5.912814321436e-001 true resid norm 5.912814321436e-001 ||Ae||/||Ax|| 8.493486526188e-001
>   2 KSP preconditioned resid norm 5.867863600876e-001 true resid norm 5.867863600876e-001 ||Ae||/||Ax|| 8.428916878189e-001
>   3 KSP preconditioned resid norm 5.743057651077e-001 true resid norm 5.743057651077e-001 ||Ae||/||Ax|| 8.249638856696e-001
>   4 KSP preconditioned resid norm 5.713990222419e-001 true resid norm 5.713990222419e-001 ||Ae||/||Ax|| 8.207884828877e-001
>   5 KSP preconditioned resid norm 5.712949806941e-001 true resid norm 5.712949806941e-001 ||Ae||/||Ax|| 8.206390319772e-001
>   6 KSP preconditioned resid norm 5.144041331498e-001 true resid norm 5.144041331499e-001 ||Ae||/||Ax|| 7.389179393110e-001
>   7 KSP preconditioned resid norm 4.642286939843e-001 true resid norm 4.642286939846e-001 ||Ae||/||Ax|| 6.668432227160e-001
>   8 KSP preconditioned resid norm 2.225622386414e-001 true resid norm 2.225622386428e-001 ||Ae||/||Ax|| 3.197004459108e-001
>   9 KSP preconditioned resid norm 6.852028979252e-002 true resid norm 6.852028979329e-002 ||Ae||/||Ax|| 9.842625296383e-002
>  10 KSP preconditioned resid norm 2.091417649890e-003 true resid norm 2.091417651046e-003 ||Ae||/||Ax|| 3.004225513287e-003
>  11 KSP preconditioned resid norm 2.221359037659e-005 true resid norm 2.221359037215e-005 ||Ae||/||Ax|| 3.190880353542e-005
>  12 KSP preconditioned resid norm 1.804209918914e-005 true resid norm 1.804209941359e-005 ||Ae||/||Ax|| 2.591664813792e-005
>  13 KSP preconditioned resid norm 1.533714545172e-005 true resid norm 1.533714905817e-005 ||Ae||/||Ax|| 2.203111104021e-005
>  14 KSP preconditioned resid norm 5.645319291054e-008 true resid norm 5.645404908731e-008 ||Ae||/||Ax|| 8.109365172072e-008
>  15 KSP preconditioned resid norm 3.193476220728e-010 true resid norm 3.097685921426e-010 ||Ae||/||Ax|| 4.449683721779e-010
>  16 KSP preconditioned resid norm 3.809088792508e-012 true resid norm 2.536256355736e-011 ||Ae||/||Ax|| 3.643215905885e-011
>   2 SNES Function norm 6.943721478945e-001 
>   0 KSP preconditioned resid norm 6.943721478945e-001 true resid norm 6.943721478945e-001 ||Ae||/||Ax|| 1.000000000000e+000
>   1 KSP preconditioned resid norm 6.312241812914e-001 true resid norm 6.312241812914e-001 ||Ae||/||Ax|| 9.090574603338e-001
>   2 KSP preconditioned resid norm 5.826977509711e-001 true resid norm 5.826977509711e-001 ||Ae||/||Ax|| 8.391721251177e-001
>   3 KSP preconditioned resid norm 5.690491242974e-001 true resid norm 5.690491242974e-001 ||Ae||/||Ax|| 8.195160563725e-001
>   4 KSP preconditioned resid norm 5.668884553347e-001 true resid norm 5.668884553347e-001 ||Ae||/||Ax|| 8.164043691178e-001
>   5 KSP preconditioned resid norm 5.667877314429e-001 true resid norm 5.667877314429e-001 ||Ae||/||Ax|| 8.162593116120e-001
>   6 KSP preconditioned resid norm 5.103464760431e-001 true resid norm 5.103464760434e-001 ||Ae||/||Ax|| 7.349754416143e-001
>   7 KSP preconditioned resid norm 4.605661569558e-001 true resid norm 4.605661569565e-001 ||Ae||/||Ax|| 6.632843185791e-001
>   8 KSP preconditioned resid norm 2.208053445289e-001 true resid norm 2.208053445308e-001 ||Ae||/||Ax|| 3.179928014111e-001
>   9 KSP preconditioned resid norm 6.797979448157e-002 true resid norm 6.797979448302e-002 ||Ae||/||Ax|| 9.790109624810e-002
>  10 KSP preconditioned resid norm 2.074808319295e-003 true resid norm 2.074808318610e-003 ||Ae||/||Ax|| 2.988035054259e-003
>  11 KSP preconditioned resid norm 2.203325006674e-005 true resid norm 2.203324811647e-005 ||Ae||/||Ax|| 3.173118072677e-005
>  12 KSP preconditioned resid norm 1.823511305062e-005 true resid norm 1.823511045569e-005 ||Ae||/||Ax|| 2.626129304147e-005
>  13 KSP preconditioned resid norm 1.735630734709e-005 true resid norm 1.735630720647e-005 ||Ae||/||Ax|| 2.499568460385e-005
>  14 KSP preconditioned resid norm 2.741404670294e-008 true resid norm 2.741193558629e-008 ||Ae||/||Ax|| 3.947729710849e-008
>  15 KSP preconditioned resid norm 1.660262277254e-010 true resid norm 1.728810158968e-010 ||Ae||/||Ax|| 2.489745828962e-010
>  16 KSP preconditioned resid norm 4.907918572393e-012 true resid norm 1.668357561843e-011 ||Ae||/||Ax|| 2.402685025461e-011
>   3 SNES Function norm 6.943722078847e-001 
> STEP 0 (Newton iterations: 3)
>  
> diverged reason: DIVERGED_LS_FAILURE
> 
> 