# dsymm.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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dsymm.f

## SYNOPSIS

### Functions/Subroutines

subroutine dsymm (SIDE, UPLO, M, N, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
DSYMM

## Function/Subroutine Documentation

### subroutine dsymm (character SIDE, character UPLO, integer M, integer N, double precision ALPHA, double precision, dimension(lda,*) A, integer LDA, double precision, dimension(ldb,*) B, integer LDB, double precision BETA, double precision, dimension(ldc,*) C, integer LDC)

DSYMM

Purpose:

``` DSYMM  performs one of the matrix-matrix operations

C := alpha*A*B + beta*C,

or

C := alpha*B*A + beta*C,

where alpha and beta are scalars,  A is a symmetric matrix and  B and
C are  m by n matrices.
```

Parameters:

SIDE

```          SIDE is CHARACTER*1
On entry,  SIDE  specifies whether  the  symmetric matrix  A
appears on the  left or right  in the  operation as follows:

SIDE = 'L' or 'l'   C := alpha*A*B + beta*C,

SIDE = 'R' or 'r'   C := alpha*B*A + beta*C,
```

UPLO

```          UPLO is CHARACTER*1
On  entry,   UPLO  specifies  whether  the  upper  or  lower
triangular  part  of  the  symmetric  matrix   A  is  to  be
referenced as follows:

UPLO = 'U' or 'u'   Only the upper triangular part of the
symmetric matrix is to be referenced.

UPLO = 'L' or 'l'   Only the lower triangular part of the
symmetric matrix is to be referenced.
```

M

```          M is INTEGER
On entry,  M  specifies the number of rows 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 C.
N  must be at least zero.
```

ALPHA

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

A

```          A is DOUBLE PRECISION array, dimension ( LDA, ka ), where ka is
m  when  SIDE = 'L' or 'l'  and is  n otherwise.
Before entry  with  SIDE = 'L' or 'l',  the  m by m  part of
the array  A  must contain the  symmetric matrix,  such that
when  UPLO = 'U' or 'u', the leading m by m upper triangular
part of the array  A  must contain the upper triangular part
of the  symmetric matrix and the  strictly  lower triangular
part of  A  is not referenced,  and when  UPLO = 'L' or 'l',
the leading  m by m  lower triangular part  of the  array  A
must  contain  the  lower triangular part  of the  symmetric
matrix and the  strictly upper triangular part of  A  is not
referenced.
Before entry  with  SIDE = 'R' or 'r',  the  n by n  part of
the array  A  must contain the  symmetric matrix,  such that
when  UPLO = 'U' or 'u', the leading n by n upper triangular
part of the array  A  must contain the upper triangular part
of the  symmetric matrix and the  strictly  lower triangular
part of  A  is not referenced,  and when  UPLO = 'L' or 'l',
the leading  n by n  lower triangular part  of the  array  A
must  contain  the  lower triangular part  of the  symmetric
matrix and the  strictly upper triangular part of  A  is not
referenced.
```

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

B

```          B is DOUBLE PRECISION array, dimension ( LDB, N )
Before entry, the leading  m by n 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.   LDB  must  be  at  least
max( 1, m ).
```

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, 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 updated
matrix.
```

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

NAG Ltd.

Date:

December 2016

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 191 of file dsymm.f.

## Author

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