strmm.f −

**Functions/Subroutines**

subroutine **strmm** (SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA, B, LDB)

STRMM

**subroutine strmm (characterSIDE, characterUPLO, characterTRANSA, characterDIAG, integerM, integerN, realALPHA, real, dimension(lda,*)A, integerLDA, real, dimension(ldb,*)B, integerLDB)
STRMM Purpose:**

STRMM performs one of the matrix-matrix operations

B := alpha*op( A )*B, or B := alpha*B*op( A ),

where alpha is a scalar, B is an m by n matrix, A is a unit, or

non-unit, upper or lower triangular matrix and op( A ) is one of

op( A ) = A or op( A ) = A**T.

**Parameters:**

*SIDE*

SIDE is CHARACTER*1

On entry, SIDE specifies whether op( A ) multiplies B from

the left or right as follows:

SIDE = ’L’ or ’l’ B := alpha*op( A )*B.

SIDE = ’R’ or ’r’ B := alpha*B*op( A ).

*UPLO*

UPLO is CHARACTER*1

On entry, UPLO specifies whether the matrix A is an upper or

lower triangular matrix as follows:

UPLO = ’U’ or ’u’ A is an upper triangular matrix.

UPLO = ’L’ or ’l’ A is a lower triangular matrix.

*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.

*DIAG*

DIAG is CHARACTER*1

On entry, DIAG specifies whether or not A is unit triangular

as follows:

DIAG = ’U’ or ’u’ A is assumed to be unit triangular.

DIAG = ’N’ or ’n’ A is not assumed to be unit

triangular.

*M*

M is INTEGER

On entry, M specifies the number of rows of B. M must be at

least zero.

*N*

N is INTEGER

On entry, N specifies the number of columns of B. N must be

at least zero.

*ALPHA*

ALPHA is REAL

On entry, ALPHA specifies the scalar alpha. When alpha is

zero then A is not referenced and B need not be set before

entry.

*A*

A is REAL array of DIMENSION ( LDA, k ), where k is m

when SIDE = ’L’ or ’l’ and is n when SIDE = ’R’ or ’r’.

Before entry with UPLO = ’U’ or ’u’, the leading k by k

upper triangular part of the array A must contain the upper

triangular matrix and the strictly lower triangular part of

A is not referenced.

Before entry with UPLO = ’L’ or ’l’, the leading k by k

lower triangular part of the array A must contain the lower

triangular matrix and the strictly upper triangular part of

A is not referenced.

Note that when DIAG = ’U’ or ’u’, the diagonal elements of

A are not referenced either, but are assumed to be unity.

*LDA*

LDA is INTEGER

On entry, LDA specifies the first dimension of A as declared

in the calling (sub) program. When SIDE = ’L’ or ’l’ then

LDA must be at least max( 1, m ), when SIDE = ’R’ or ’r’

then LDA must be at least max( 1, n ).

*B*

B is REAL array of DIMENSION ( LDB, n ).

Before entry, the leading m by n part of the array B must

contain the matrix B, and on exit is overwritten by the

transformed matrix.

*LDB*

LDB is INTEGER

On entry, LDB specifies the first dimension of B as declared

in the calling (sub) program. LDB 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 178 of file strmm.f.

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