[Trilinos-Users] Complex sparse matrix vector product focusing on load balancing

[Heroux, Mike]

Zifan,

One approach to consider with Epetra is to split the complex vectors into real and imaginary parts.  Essentially you would have an Epetra multivector with two columns, the first being the real coefficients and the second being the imaginary coefficients.

Since your matrix is real-valued, there is no mixing of real and imaginary parts of x  when computing y, so computing y = Ax is just a sparse matrix multiply with two right-hand-sides.

Epetra does support this operation.

I think this approach would be more effective than trying to use complex arithmetic, because your matrix has no imaginary component.

Does this help?

Mike

On Dec 11, 2013, at 6:47 AM, "Zifan Liu" <zif.liu at gmail.com<mailto:zif.liu at gmail.com>> wrote:

Hello,

I want to write a sparse matrix vector product kernel using trilinos.

y=A*x
where A is a large sparse real valued matrix.
Vector x is a complex valued vector.
Vector y is the result.

The main steps and my solutions are the following:

- Read the real-valued sparse matrix from a matlab file.---> Use "EpetraExt::MatlabFileToCrsMatrix()" function.

- Perform load balancing and redistribute the data ---> Use "Isorropia::Epetra::createBalancedCopy" function.

- Generate my complex vector x ---> ?

- Perform the MVP y=A*x ---> ?

Here, since the vector x is a complex valued vector, does Epetra support complex valued vector and complex valued MVP ?

If not, can we perform load balancing and redistribute the matrix data using Tpetra ? Is there an example about this ?

Thanks for your help,

Z. L.
--
Mr. LIU Zifan

Lab. PRiSM, University of Versailles, 45 avenue des Etats-Unis, 78035 Versailles cedex FRANCE

Maison de la simulation, Digiteo Labs-Bâtiment 565-PC 190, CEA/Saclay, 91191 Gif-sur-Yvette cedex FRANCE

Tel (+33) 1 39 25 43 43
Cell (+33) 6 42 03 25 96
zifan.liu at prism.uvsq.fr<mailto:zifan.liu at prism.uvsq.fr>
zif.liu at gmail.com<mailto:zif.liu at gmail.com>
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