---
name: "dsymm.f"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/dsymm.f"
---

# dsymm.f(3)

## NAME

BLAS/SRC/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

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 **188** of file **dsymm.f**.

## Author

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