blas_init(3) BLAS routine of NEC Numeric Library Collection blas_init(3) NAME blas_init SYNOPSIS SUBROUTINE blas_init() DESCRIPTION Retrieves the value of the environment variables for BLAS routines. ARGUMENTS None. ENVIRONENT VARIABLES The following environment variables are referenced by this routine. VE_BLAS_DGEMM_MODE Specifies the DGEMM algorithm. = auto, 0 Automatic selection. (default) = dot, 1 DOT algorithm is used. = greedya, 2 GREEDYA algorithm is used. The algorithm minimizes the number of loading/storing elements of the matrix A. = greedyc, 3 GREEDYC algorithm is used. The algorithm minimizes the number of loading/storing elements of the matrix C. VE_BLAS_DGEMM_USE_FMA Specifies whether DGEMM uses vector fused-multiply-add instructions. = yes, 1 DGEMM uses vector fused-multiply-add instructions. (default) = no, 0 DGEMM does not use vector fused-multiply-add instructions. EXAMPLE Please call blas_init() only once before calling other BLAS routines. For Fortran call blas_init() . . . call dgemm(. . .) For C void blas_init(); int main(void){ blas_init(); . . . cblas_dgemm(. . .); NOTES This routine must not be called in a OpenMP parallel region because the routine is NOT reentrant. BLAS routine blas_init(3)