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Questions tagged [blas]

Basic Linear Algebra Subprograms - A standard API library with vector-vector, matrix-vector, and matrix-matrix operations.

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74
votes
6answers
17k views

How much better are Fortran compilers really?

This question is an extension of two discussions that came up recently in the replies to "C++ vs Fortran for HPC". And it is a bit more of a challenge than a question... One of the most often-heard ...
15
votes
3answers
2k views

Why isn't my Matrix-Vector Multiplication Scaling?

Sorry for the long post but I wanted to include everything that I thought was relevant in the first go. What I want I am implementing a parallel version of Krylov Subspace Methods for Dense Matrices....
5
votes
3answers
1k views

Performance optimization or tuning possible for Scalapack Gemm?

I'm comparing the performance of distributed gemm, using Scalapack over OpenBLAS, with threaded gemm, using OpenBLAS. It seems quite hard for me to get scalapack to give better results than ...
6
votes
1answer
2k views

What is the best way to multiply a diagonal matrix (in fortran)

What is the best way to compute: $$ Y = D X $$ where $D \in \mathbb{R}^{m\times m}$ is diagonal and $X \in \mathbb{C}^{m \times n}$ is general. I am mostly interested in these two cases: $m >> ...
3
votes
2answers
1k views

How Do I solve large systems given UMFPACK memory limitations?

I am trying to solve a system of equations (A x = b) for 3D heat diffusion (i.e. each equation has at most 7 terms not including the constant "b" term) using UMFPACK with boost numeric bindings to C++....
3
votes
1answer
2k views

Intel MKL - Difference between mkl_intel_lp64 and mkl_gf_lp64

I am currently trying to link a program against the Intel MKL 11.0 library instead of using NetLIB or OpenBLAS. Doing this I recognized the following error which I can not explain to my self at the ...