dgemm.f man page

dgemm.f —

Synopsis

Functions/Subroutines

subroutine dgemm (TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
DGEMM

Function/Subroutine Documentation

subroutine dgemm (characterTRANSA, characterTRANSB, integerM, integerN, integerK, double precisionALPHA, double precision, dimension(lda,*)A, integerLDA, double precision, dimension(ldb,*)B, integerLDB, double precisionBETA, double precision, dimension(ldc,*)C, integerLDC)

DGEMM 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**T,

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.

Parameters:

TRANSA

TRANSA is CHARACTER*1
 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**T.

    TRANSA = 'C' or 'c',  op( A ) = A**T.

TRANSB

TRANSB is CHARACTER*1
 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**T.

    TRANSB = 'C' or 'c',  op( B ) = B**T.

M

M is INTEGER
 On entry,  M  specifies  the number  of rows  of the  matrix
 op( A )  and of the  matrix  C.  M  must  be at least  zero.

N

N is INTEGER
 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.

K

K is INTEGER
 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.

ALPHA

ALPHA is DOUBLE PRECISION.
 On entry, ALPHA specifies the scalar alpha.

A

A is DOUBLE PRECISION array of DIMENSION ( LDA, ka ), where ka is
 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.

LDA

LDA is INTEGER
 On entry, LDA specifies the first dimension of A as declared
 in the calling (sub) program. When  TRANSA = 'N' or 'n' then
 LDA must be at least  max( 1, m ), otherwise  LDA must be at
 least  max( 1, k ).

B

B is DOUBLE PRECISION array of DIMENSION ( LDB, kb ), where kb is
 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.

LDB

LDB is INTEGER
 On entry, LDB specifies the first dimension of B as declared
 in the calling (sub) program. When  TRANSB = 'N' or 'n' then
 LDB must be at least  max( 1, k ), otherwise  LDB must be at
 least  max( 1, n ).

BETA

BETA is DOUBLE PRECISION.
 On entry,  BETA  specifies the scalar  beta.  When  BETA  is
 supplied as zero then C need not be set on input.

C

C is DOUBLE PRECISION array of DIMENSION ( LDC, n ).
 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

LDC is INTEGER
 On entry, LDC specifies the first dimension of C as declared
 in  the  calling  (sub)  program.   LDC  must  be  at  least
 max( 1, m ).

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Further Details:

Level 3 Blas routine.

-- Written on 8-February-1989.
   Jack Dongarra, Argonne National Laboratory.
   Iain Duff, AERE Harwell.
   Jeremy Du Croz, Numerical Algorithms Group Ltd.
   Sven Hammarling, Numerical Algorithms Group Ltd.

Definition at line 188 of file dgemm.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dgemm(3) is an alias of dgemm.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK