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blasintel-mkl

Standart rowwise vector matrix operations

I am searching for rowwise vector matrix operations( I think that should be BLAS level 2 routines). For example to substruct a vector from a matrix rowwise, or to normalize matrix by it rows sum. Are there such optimized standard routines?

Solution

  • Unfortunately, there is no such operation in BLAS. All the available subroutines are listed here: http://www.netlib.org/lapack/lug/node145.html

    You can write your own subroutines and call BLAS level 1 for jobs like norm, axpy, etc... However, the gain in performance is generally modest.

    -> BLAS is really important for matrix-matrix (or matrix-vector) products where cache management, data locality and access pattern make a really big difference (in perfs).