• NAME
• SYNOPSIS
• F95 INTERFACE
• C INTERFACE
• PURPOSE
• ARGUMENTS

NAME

dgemm - perform one of the matrix-matrix operations C := alpha*op( A )*op( B ) + beta*C

SYNOPSIS

  SUBROUTINE DGEMM( TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, 
 *      BETA, C, LDC)
  CHARACTER * 1 TRANSA, TRANSB
  INTEGER M, N, K, LDA, LDB, LDC
  DOUBLE PRECISION ALPHA, BETA
  DOUBLE PRECISION A(LDA,*), B(LDB,*), C(LDC,*)

  SUBROUTINE DGEMM_64( TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, 
 *      BETA, C, LDC)
  CHARACTER * 1 TRANSA, TRANSB
  INTEGER*8 M, N, K, LDA, LDB, LDC
  DOUBLE PRECISION ALPHA, BETA
  DOUBLE PRECISION A(LDA,*), B(LDB,*), C(LDC,*)

F95 INTERFACE

  SUBROUTINE GEMM( [TRANSA], [TRANSB], [M], [N], [K], ALPHA, A, [LDA], 
 *       B, [LDB], BETA, C, [LDC])
  CHARACTER(LEN=1) :: TRANSA, TRANSB
  INTEGER :: M, N, K, LDA, LDB, LDC
  REAL(8) :: ALPHA, BETA
  REAL(8), DIMENSION(:,:) :: A, B, C

  SUBROUTINE GEMM_64( [TRANSA], [TRANSB], [M], [N], [K], ALPHA, A, 
 *       [LDA], B, [LDB], BETA, C, [LDC])
  CHARACTER(LEN=1) :: TRANSA, TRANSB
  INTEGER(8) :: M, N, K, LDA, LDB, LDC
  REAL(8) :: ALPHA, BETA
  REAL(8), DIMENSION(:,:) :: A, B, C

C INTERFACE

#include <sunperf.h>

void dgemm(char transa, char transb, int m, int n, int k, double alpha, double *a, int lda, double *b, int ldb, double beta, double *c, int ldc);

void dgemm_64(char transa, char transb, long m, long n, long k, double alpha, double *a, long lda, double *b, long ldb, double beta, double *c, long ldc);

PURPOSE

dgemm performs one of the matrix-matrix operations C := alpha*op( A )*op( B ) + beta*C where op( X ) is one of

   op( X ) = X   or   op( X ) = X',

alpha and beta are scalars, and A, B and C are matrices, with op( A ) an m by k matrix, op( B ) a k by n matrix and C an m by n matrix.

ARGUMENTS

• TRANSA (input)
  On entry, TRANSA specifies the form of op( A ) to be used in the matrix multiplication as follows:

  TRANSA = 'N' or 'n', op( A ) = A.

  TRANSA = 'T' or 't', op( A ) = A'.

  TRANSA = 'C' or 'c', op( A ) = A'.

  Unchanged on exit.

• TRANSB (input)
  On entry, TRANSB specifies the form of op( B ) to be used in the matrix multiplication as follows:

  TRANSB = 'N' or 'n', op( B ) = B.

  TRANSB = 'T' or 't', op( B ) = B'.

  TRANSB = 'C' or 'c', op( B ) = B'.

  Unchanged on exit.

• M (input)
  On entry, M specifies the number of rows of the matrix op( A ) and of the matrix C. M must be at least zero. Unchanged on exit.

• N (input)
  On entry, N specifies the number of columns of the matrix op( B ) and the number of columns of the matrix C. N must be at least zero. Unchanged on exit.

• K (input)
  On entry, K specifies the number of columns of the matrix op( A ) and the number of rows of the matrix op( B ). K must be at least zero. Unchanged on exit.

• ALPHA (input)
  On entry, ALPHA specifies the scalar alpha. Unchanged on exit.

• A (input)
  k when TRANSA = 'N' or 'n', and is m otherwise. Before entry with TRANSA = 'N' or 'n', the leading m by k part of the array A must contain the matrix A, otherwise the leading k by m part of the array A must contain the matrix A. Unchanged on exit.

• LDA (input)
  On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. When TRANSA = 'N' or 'n' then LDA > = max( 1, m ), otherwise LDA > = max( 1, k ). Unchanged on exit.

• B (input)
  n when TRANSB = 'N' or 'n', and is k otherwise. Before entry with TRANSB = 'N' or 'n', the leading k by n part of the array B must contain the matrix B, otherwise the leading n by k part of the array B must contain the matrix B. Unchanged on exit.

• LDB (input)
  On entry, LDB specifies the first dimension of B as declared in the calling (sub) program. When TRANSB = 'N' or 'n' then LDB > = max( 1, k ), otherwise LDB > = max( 1, n ). Unchanged on exit.

• BETA (input)
  On entry, BETA specifies the scalar beta. When BETA is supplied as zero then C need not be set on input. Unchanged on exit.

• C (input/output)
  Before entry, the leading m by n part of the array C must contain the matrix C, except when beta is zero, in which case C need not be set on entry. On exit, the array C is overwritten by the m by n matrix ( alpha*op( A )*op( B ) + beta*C ).

• LDC (input)
  On entry, LDC specifies the first dimension of C as declared in the calling (sub) program. LDC > = max( 1, m ). Unchanged on exit.