Hi,
I have made a small test including MKL and MAGMA eigenvectors/eigenvalues calculation. I thought it could be due to my data, but it also gives wrong results using the random double matrix generator. For small values (14  32) of N, it gives right results, however it doesn't give the right value for eigenvectors for large values of N (1024 onwards). It always gives right results for eigenvalues though. Is that a bug?
Possible bug dsyevd_gpu test wrong eigenvectors result
Possible bug dsyevd_gpu test wrong eigenvectors result
 Attachments

 test.tar.gz
 (2.57 KiB) Downloaded 100 times
Re: Possible bug dsyevd_gpu test wrong eigenvectors result
Hi Stan,
Did you have a chance to run my test? I've run the test on the Fermi C2050 cards. I have not tried on the K20s yet, but I guess it will hav ethe same effect.
Have you ever heard anything else from anybody about that?
Thanks for your help.
Luis
Did you have a chance to run my test? I've run the test on the Fermi C2050 cards. I have not tried on the K20s yet, but I guess it will hav ethe same effect.
Have you ever heard anything else from anybody about that?
Thanks for your help.
Luis

 Posts: 264
 Joined: Fri Aug 21, 2009 10:39 pm
Re: Possible bug dsyevd_gpu test wrong eigenvectors result
Hi Luis,
I just ran the test and reproduced your result on a K20c.
I added a check for the factorization though and for the orthogonality and everything looks fine:
I added the check at the end of calcMAGMA.cc with the following code:
Similar check for the LAPACK result gives that the factorization is correct and the eigenvectors are orthogonal:
I suppose this has to do with the directions of the vectors, or if there are repeated eigenvalues we may have chosen different than LAPACK corresponding eigenvectors. Is it important for you that the result matches the LAPACK results?
Stan
I just ran the test and reproduced your result on a K20c.
I added a check for the factorization though and for the orthogonality and everything looks fine:
Code: Select all
test> ./benchmark_cpu N 2000
Reading input file
Read succesful
Calculating eigenvalues with MKL
Quering space...
Solving eigenvalues...
Calculating eigenvalues with MAGMA
Quering for workspace
Warming up...
Quering optimal sizes...
Performing MAGMA operation...
Successful calculation of eigenvectors/eigenvalues
Testing the factorization A = U S U' for correctness:
(1)  A  U S U'  / (A N) = 3.670771e18
(2)  I  U'U  / N = 6.732193e17
Eigenvalues: SUCESS!!!!
Calculating max difference eigenvectors ...
ERROR: max diff = 1.088852
Code: Select all
double result[3], eps = lapackf77_dlamch( "E" );
lapackf77_dsyt21( &ione, uplo, &N, &izero,
A, &N,
w, h_work,
Ar, &N,
Ar, &N,
NULL, h_work, &result[0] );
printf("Testing the factorization A = U S U' for correctness:\n");
printf("(1)  A  U S U'  / (A N) = %e\n", result[0]*eps);
printf("(2)  I  U'U  / N = %e\n", result[1]*eps);
Code: Select all
Testing the factorization A = U S U' for correctness:
(1)  A  U S U'  / (A N) = 4.021844e18
(2)  I  U'U  / N = 1.075072e16
Stan
Re: Possible bug dsyevd_gpu test wrong eigenvectors result
I understand...And yes, your are right. Mathematically the result is correct, but for some reason they are different to the ones calculated with LAPACK. It seems that is important that eigenvectors match the LAPACK eigenvectors within my application...
Re: Possible bug dsyevd_gpu test wrong eigenvectors result
Hi, Stan!
I was using the default "testing_dsyevd" and "testing_dsyevd_gpu" in the "testing" directory in MAGMA v1.3.0. If a very small matrix, e.g. 10x10 matrix, was specified, then it gave some error messages.
Could you please help me to fix this problme?
Thank you!
/* the output */
xwu@t2090th1:~/magma/magma1.3.0/testing> ./testing_dsyevd_gpu N 10
MAGMA 1.3.0
device 0: Tesla M2090, 1301.0 MHz clock, 5375.4 MB memory, capability 2.0
device 1: Tesla M2090, 1301.0 MHz clock, 5375.4 MB memory, capability 2.0
testing_dsyevd N 10 [JV] [JN]
N CPU Time(s) GPU Time(s)
===================================
MKL ERROR: Parameter 11 was incorrect on entry to magma_dsytrd_gpu.
MKL ERROR: Parameter 11 was incorrect on entry to magma_dsytrd_gpu.
10 0.00 0.00
xwu@t2090th1:~/magma/magma1.3.0/testing> ./testing_dsyevd N 10
MAGMA 1.3.0
device 0: Tesla M2090, 1301.0 MHz clock, 5375.4 MB memory, capability 2.0
device 1: Tesla M2090, 1301.0 MHz clock, 5375.4 MB memory, capability 2.0
testing_dsyevd N 10 [JV] [JN]
N CPU Time(s) GPU Time(s)
===================================
MKL ERROR: Parameter 9 was incorrect on entry to magma_dsytrd.
MKL ERROR: Parameter 9 was incorrect on entry to magma_dsytrd.
10 0.00 0.00
I was using the default "testing_dsyevd" and "testing_dsyevd_gpu" in the "testing" directory in MAGMA v1.3.0. If a very small matrix, e.g. 10x10 matrix, was specified, then it gave some error messages.
Could you please help me to fix this problme?
Thank you!
/* the output */
xwu@t2090th1:~/magma/magma1.3.0/testing> ./testing_dsyevd_gpu N 10
MAGMA 1.3.0
device 0: Tesla M2090, 1301.0 MHz clock, 5375.4 MB memory, capability 2.0
device 1: Tesla M2090, 1301.0 MHz clock, 5375.4 MB memory, capability 2.0
testing_dsyevd N 10 [JV] [JN]
N CPU Time(s) GPU Time(s)
===================================
MKL ERROR: Parameter 11 was incorrect on entry to magma_dsytrd_gpu.
MKL ERROR: Parameter 11 was incorrect on entry to magma_dsytrd_gpu.
10 0.00 0.00
xwu@t2090th1:~/magma/magma1.3.0/testing> ./testing_dsyevd N 10
MAGMA 1.3.0
device 0: Tesla M2090, 1301.0 MHz clock, 5375.4 MB memory, capability 2.0
device 1: Tesla M2090, 1301.0 MHz clock, 5375.4 MB memory, capability 2.0
testing_dsyevd N 10 [JV] [JN]
N CPU Time(s) GPU Time(s)
===================================
MKL ERROR: Parameter 9 was incorrect on entry to magma_dsytrd.
MKL ERROR: Parameter 9 was incorrect on entry to magma_dsytrd.
10 0.00 0.00