BLAS Option

Type

Selection

Range

The settings listed below

Default

Intel

This option specifies the BLAS/LAPACK function library to use for basic vector and matrix computations. Possible values are:

  • Automatic

  • Off

  • Intel

BLAS (Basic Linear Algebra Subroutines) and LAPACK (Linear Algebra PACKage) functions are used throughout Knitro for fundamental vector and matrix calculations. Some optimization problems are observed to spend very little CPU time in BLAS/LAPACK operations, while others spend more than 50%. Be aware that the different function implementations can return slightly different answers due to roundoff errors in double precision arithmetic. Thus, changing the value of this option sometimes alters the iterates generated by Knitro, or even the final solution point.

Note

  • Repeating the same solve using setting ‘Intel’ can result in a different solution on a 32 bits computer.

  • The option Number of BLAS Threads determines the number of threads to be used in case the BLAS/LAPACK function library is selected.

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