test cases for GMRES and CG

[Matthew Knepley]

On Wed, Jul 16, 2008 at 7:20 PM, Yipkei Kwok <ykwok2 at miners.utep.edu> wrote:
> Hi,
>
> Question 1: Test case results for GMRES, one of the Krylov Subspace Methods,
> do not match the standard results.

These appear to be normal floating point roundoff effects.

> Question 2: Where can I found test cases for CG, another Krylov Subspace
> Method?

You can run all tests using 'make testexamples'

  Matt

> [Question 1: Test case results for GMRES, one of the Krylov Subspace
> Methods, do not match the standard results.]
> I have installed PETSc 2.3.3 on an Itanium 2 machine.
>
> Then, I tried to verify the correctness of the installation by running test
> cases in the following directory.
> src/ksp/ksp/examples/tests
>
> I got the following error when running example 17
> $ make runex17
> 17c17
> <  16 KSP Residual norm 4.19038e-08
> ---
>>  16 KSP Residual norm 2.9736e-07
> 29c29
> <     type=aij, rows=36, cols=36
> ---
>>     type=seqaij, rows=36, cols=36
> 32c32
> < Norm of error 9.90874e-10, Iterations 16
> ---
>> Norm of error 7.03149e-09,Iterations 16
> Possible problem with ex17_1, diffs above
>
>
>
>
>
> And, I got the following error when running the example 19.
> $ make runex19
> 3,21c3,22
> <   0 KSP Residual norm 2.34801
> <   1 KSP Residual norm 1.10991
> <   2 KSP Residual norm 0.905352
> <   3 KSP Residual norm 0.719343
> <   4 KSP Residual norm 0.542882
> <   5 KSP Residual norm 0.378135
> <   6 KSP Residual norm 0.2063
> <   7 KSP Residual norm 0.0785186
> <   8 KSP Residual norm 0.0271851
> <   9 KSP Residual norm 0.0154188
> <  10 KSP Residual norm 0.00984534
> <  11 KSP Residual norm 0.00604218
> <  12 KSP Residual norm 0.00189778
> <  13 KSP Residual norm 0.000708898
> <  14 KSP Residual norm 0.000230128
> <  15 KSP Residual norm 9.31276e-05
> <  16 KSP Residual norm 3.83561e-05
> <  17 KSP Residual norm 2.04223e-05
> < Number of iterations = 17
> ---
>>   0 KSP Residual norm 2.90126
>>   1 KSP Residual norm 1.45832
>>   2 KSP Residual norm 1.18005
>>   3 KSP Residual norm 0.941127
>>   4 KSP Residual norm 0.696937
>>   5 KSP Residual norm 0.484776
>>   6 KSP Residual norm 0.245944
>>   7 KSP Residual norm 0.102339
>>   8 KSP Residual norm 0.0501583
>>   9 KSP Residual norm 0.0346147
>>  10 KSP Residual norm 0.0196042
>>  11 KSP Residual norm 0.0102261
>>  12 KSP Residual norm 0.00331366
>>  13 KSP Residual norm 0.00153735
>>  14 KSP Residual norm 0.000698171
>>  15 KSP Residual norm 0.000356882
>>  16 KSP Residual norm 0.000136588
>>  17 KSP Residual norm 5.23453e-05
>>  18 KSP Residual norm 1.50308e-05
>> Number of iterations = 18
> Possible problem with ex19_1, diffs above
>
> Does anyone have a clue why the results are different?
>
> Note that I also have PETSc installed on a Xeon machine. The results
> generated on the Xeon match the results generated on the Itanium 2 machine
> for ex19. But, for ex17, the results generated on the Xeon machine match
> neither the standard results nor the results generated on the Itanium 2
> machine.
>
>
>
>
>
>
> [Question 2: Where can I find test cases for CG, another Krylov Subspace
> Method?]
>
> ex17 and ex19 in the src/ksp/ksp/examples/tests directory are using the
> GMRES method. We want to make sure that the CG method is working correctly.
> The option `-ksp_type cg' does not appear in any test case of that
> directory. Where can I find test cases for CG? Or, is there anyway that I
> can verify the correctness of the CG installation?
>
>
>
> [Extra information]
> Here is the machine configuration.
> Four Intel Itanium 2 processor
> 8GB memory
> Red Hat Enterprise Linux AS release 4 (Nahant Update 5)
> gcc 3.4.6
> gfortran 4.1.1
> PETSc Configure Options: --with-mpi=0 --prefix=/usr/local/EE/ --with-x=0
> --with-x11=0
> -download-c-blas-lapack=ifneeded -download-f-blas-lapack=ifneeded
> --with-shared=
> 0 --with-scalar-type=complex --configModules=PETSc.Configure
> --optionsModule=PETSc.compilerOptions
>
> Please note that the option `--with-mpi=0' is used as we want a sequential
> version of PETSc.
>
>
>
> Thank you very much!
>
> Regards,
> Yipkei
>
> --
> Join the We Campaign! (http://www.wecansolveit.org/)
>
> ********************************************
> Yipkei Kwok
> Ph.D. Student
> Research Assistant
> HiPerSys Lab
> Department of Computer Science
> The University of Texas at El Paso
> Phone: 915 747 6433 (O)
> E-mail: ykwok2 at miners dot utep dot edu
> ********************************************
>
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which
their experiments lead.
-- Norbert Wiener