strsm.f - Man Page

BLAS/SRC/strsm.f

Synopsis

Functions/Subroutines

subroutine strsm (side, uplo, transa, diag, m, n, alpha, a, lda, b, ldb)
STRSM

Function/Subroutine Documentation

subroutine strsm (character side, character uplo, character transa, character diag, integer m, integer n, real alpha, real, dimension(lda,*) a, integer lda, real, dimension(ldb,*) b, integer ldb)

STRSM

Purpose:

``` STRSM  solves one of the matrix equations

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

where alpha is a scalar, X and B are m by n matrices, 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.

The matrix X is overwritten on B.```
Parameters

SIDE

```          SIDE is CHARACTER*1
On entry, SIDE specifies whether op( A ) appears on the left
or right of X as follows:

SIDE = 'L' or 'l'   op( A )*X = alpha*B.

SIDE = 'R' or 'r'   X*op( A ) = alpha*B.```

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 k 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  right-hand  side  matrix  B,  and  on exit  is
overwritten by the solution matrix  X.```

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 180 of file strsm.f.

Author

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Referenced By

The man page strsm(3) is an alias of strsm.f(3).

Tue Nov 28 2023 12:08:41 Version 3.12.0 LAPACK