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How to do A*B and A*x only

Posted: Wed Apr 03, 2013 10:28 pm
by cz0397
Hi!
I am trying to use Jacobi iteration on magma. And I know the functions(sgemv and sgemm), but it must be A*B + C and A*X + y, which do something unnecessary. Does the lapack or magma fix this problem, or if I put zero in C or y, it will not be computed?

Thanks for answering.
David

Re: How to do A*B and A*x only

Posted: Wed Apr 10, 2013 12:47 am
by cz0397
Is the only way is to set beta 0? By lapack, when setting beta 0, it won't computing the rest.

Re: How to do A*B and A*x only

Posted: Wed Apr 10, 2013 3:37 pm
by mgates3
Yes, set beta=0. Also, y or C should be initialized to valid numbers, i.e., not NAN or INF, which would be propagated.
-mark

Re: How to do A*B and A*x only

Posted: Mon May 06, 2013 6:31 am
by luiceur
I use cudaMemset to make sure there is not garbage in that section of memory