BLAS/SRC/strmm.f(3) Library Functions Manual BLAS/SRC/strmm.f(3)

BLAS/SRC/strmm.f


subroutine strmm (side, uplo, transa, diag, m, n, alpha, a, lda, b, ldb)
STRMM

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, 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, 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.

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 176 of file strmm.f.

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