a basic question on ScaLAPACK

Post here if you have a question about LAPACK or ScaLAPACK algorithm or data format

a basic question on ScaLAPACK

Postby Powergon » Thu Jan 31, 2013 4:06 pm

I am new user of ScaLAPACK. I have a very basic question:

Given a matrix 'A", we can build a process grid and distribute the matrix data onto the grids and then call some ScalAPACK routines.

In the variable list of the routine, say, eigensolver:
pdsyev (jobz, uplo, n, a, ia, ja, desc_a, w, z, iz, jz, desc_z, work, lwork, info);

what is the matrix variable "a" on the entry actually? Is it using the whole global matrix "A" or just local distributed submatrix?

If it's just the local distributed submatrix, then what if now, my matrix has already been distributed, stored in local matrix "a", and I know exactly the block cyclic distribution mapping between the global and local indices. So, without gathering back all the data to form a single matrix "A", can I call the ScaLAPACK routines ?

I hope I am expressing myself clear....

Thank you very much !

Posts: 12
Joined: Sat Sep 22, 2012 12:42 pm

Return to Algorithm / Data

Who is online

Users browsing this forum: No registered users and 1 guest