# cgemm.f (3) - Linux Manuals

cgemm.f -

## SYNOPSIS

### Functions/Subroutines

subroutine cgemm (TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
CGEMM

## Function/Subroutine Documentation

### subroutine cgemm (characterTRANSA, characterTRANSB, integerM, integerN, integerK, complexALPHA, complex, dimension(lda,*)A, integerLDA, complex, dimension(ldb,*)B, integerLDB, complexBETA, complex, dimension(ldc,*)C, integerLDC)

CGEMM Purpose:

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

C := alpha*op( A )*op( B ) + beta*C,

where  op( X ) is one of

op( X ) = X   or   op( X ) = X**T   or   op( X ) = X**H,

alpha and beta are scalars, and A, B and C are matrices, with op( A )
an m by k matrix,  op( B )  a  k by n matrix and  C an m by n matrix.
```

Parameters:

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**H.
```

TRANSB

```          TRANSB is CHARACTER*1
On entry, TRANSB specifies the form of op( B ) to be used in
the matrix multiplication as follows:

TRANSB = 'N' or 'n',  op( B ) = B.

TRANSB = 'T' or 't',  op( B ) = B**T.

TRANSB = 'C' or 'c',  op( B ) = B**H.
```

M

```          M is INTEGER
On entry,  M  specifies  the number  of rows  of the  matrix
op( A )  and 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
op( B ) and the number of columns of the matrix C. N must be
at least zero.
```

K

```          K is INTEGER
On entry,  K  specifies  the number of columns of the matrix
op( A ) and the number of rows of the matrix op( B ). K must
be at least  zero.
```

ALPHA

```          ALPHA is COMPLEX
On entry, ALPHA specifies the scalar alpha.
```

A

```          A is COMPLEX array of DIMENSION ( LDA, ka ), where ka is
k  when  TRANSA = 'N' or 'n',  and is  m  otherwise.
Before entry with  TRANSA = 'N' or 'n',  the leading  m by k
part of the array  A  must contain the matrix  A,  otherwise
the leading  k by m  part of the array  A  must contain  the
matrix A.
```

LDA

```          LDA is INTEGER
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. When  TRANSA = 'N' or 'n' then
LDA must be at least  max( 1, m ), otherwise  LDA must be at
least  max( 1, k ).
```

B

```          B is COMPLEX array of DIMENSION ( LDB, kb ), where kb is
n  when  TRANSB = 'N' or 'n',  and is  k  otherwise.
Before entry with  TRANSB = 'N' or 'n',  the leading  k by n
part of the array  B  must contain the matrix  B,  otherwise
the leading  n by k  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. When  TRANSB = 'N' or 'n' then
LDB must be at least  max( 1, k ), otherwise  LDB must be at
least  max( 1, n ).
```

BETA

```          BETA is COMPLEX
On entry,  BETA  specifies the scalar  beta.  When  BETA  is
supplied as zero then C need not be set on input.
```

C

```          C is COMPLEX array of 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  matrix
( alpha*op( A )*op( B ) + beta*C ).
```

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.

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 188 of file cgemm.f.

## Author

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