# elpa_hermitian_multiply - Man Page

Performs C = A**H * B

## Synopsis

### Fortran Interface

use elpa
class(elpa_t), pointer :: elpa

call elpa%hermitian_multiply (uplo_a, uplo_c, ncb, a, b, nrows_b, ncols_b, &
c, nrows_c, ncols_c, error)"

With the definitions of the input and output variables:

character*1 :: uplo_a

set to 'U' if A is upper triangular, 'L' if A is lower triangular or anything else if A is a full matrix

character*1 :: uplo_c

set to 'U' if only the upper diagonal part of C is needed, to 'L' if only the upper diagonal part of C is needed, or to anything else if the full matrix C is needed

integer :: ncb

The number of columns of the global matrices b and c

datatype :: a

The matrix a. The dimensions of matrix a must be set BEFORE with the methods elpa_set(3) and elpa_setup(3). The datatype of the matrix can be one of "real(kind=c_double)", "real(kind=c_float)", "complex(kind=c_double)", or "complex(kind=c_float)"

datatype :: b

The matrix b. The dimensions of the matrix are specified by the parametes nrows_b and ncols_b. The datatype of the matrix can be one of "real(kind=c_double)", "real(kind=c_float)", "complex(kind=c_double)", or "complex(kind=c_float)"

integer :: nrows_b

The number of rows of matrix b

integer :: ncols_b

The number of columns of matrix b

datatype :: c

The matrix c. The dimensions of the matrix are specified by the parametes nrows_c and ncols_c. The datatype of the matrix can be one of "real(kind=c_double)", "real(kind=c_float)", "complex(kind=c_double)", or "complex(kind=c_float)"

integer :: nrows_c

The number of rows of matrix c

integer :: ncols_c

The number of columns of matrix c

integer, optional :: error

The return error code of the function. Should be "ELPA_OK". The error code can be querried with the function elpa_strerr(3)

### C Interface

#include <elpa/elpa.h>
elpa_t handle;

void elpa_hermitian_multiply(elpa_t handle, char uplo_a, char uplo_c, int ncb, datatype *a, datatype *b, int nrows_b, int ncols_b, datatype *c, int nrows_c, int ncols_c, int *error);

With the definitions of the input and output variables:

elpa_t handle;

The handle to the ELPA object

char uplo_a;

set to 'U' if A is upper triangular, 'L' if A is lower triangular or anything else if A is a full matrix

char uplo_c;

set to 'U' if only the upper diagonal part of C is needed, to 'L' if only the upper diagonal part of C is needed, or to anything else if the full matrix C is needed

int ncb;

The number of columns of the global matrices b and c

datatype *a;

The matrix a. The dimensions of matrix a must be set BEFORE with the methods elpa_set(3) and elpa_setup(3). The datatype of the matrix can be one of "double", "float", "double complex", or "float complex"

datatype *b;

The matrix b. The dimensions of the matrix are specified by the parametes nrows_b and ncols_b. The datatype of the matrix can be one of "double", "float", "double complex", or "float complex"

int nrows_b;

The number of rows of matrix b

int ncols_b;

The number of columns of matrix b

datatype *c;

The matrix c. The dimensions of the matrix are specified by the parametes nrows_c and ncols_c. The datatype of the matrix can be one of "double", "float", "double complex", or "float complex"

int nrows_c;

The number of rows of matrix c

int ncols_c;

The number of columns of matrix c

int *error

The return error code of the function. Should be "ELPA_OK". The error code can be querried with the function elpa_strerr(3)

## Description

Performa a "hermitian" multiplication C = A**T * B for real matrices and C=A**H * B for complex matrices. The functions elpa_init(3), elpa_allocate(3), elpa_set(3), and elpa_setup(3) must be called BEFORE elpa_hermitian_multiply can be called.

## Referenced By

Sat Jul 15 2017 ELPA