zherk(3P) Sun Performance Library zherk(3P)NAMEzherk - perform one of the Hermitian rank k operations C :=
alpha*A*conjg( A' ) + beta*C or C := alpha*conjg( A' )*A + beta*C
SYNOPSIS
SUBROUTINE ZHERK(UPLO, TRANSA, N, K, ALPHA, A, LDA, BETA, C, LDC)
CHARACTER * 1 UPLO, TRANSA
DOUBLE COMPLEX A(LDA,*), C(LDC,*)
INTEGER N, K, LDA, LDC
DOUBLE PRECISION ALPHA, BETA
SUBROUTINE ZHERK_64(UPLO, TRANSA, N, K, ALPHA, A, LDA, BETA, C, LDC)
CHARACTER * 1 UPLO, TRANSA
DOUBLE COMPLEX A(LDA,*), C(LDC,*)
INTEGER*8 N, K, LDA, LDC
DOUBLE PRECISION ALPHA, BETA
F95 INTERFACE
SUBROUTINE HERK(UPLO, [TRANSA], [N], [K], ALPHA, A, [LDA], BETA, C,
[LDC])
CHARACTER(LEN=1) :: UPLO, TRANSA
COMPLEX(8), DIMENSION(:,:) :: A, C
INTEGER :: N, K, LDA, LDC
REAL(8) :: ALPHA, BETA
SUBROUTINE HERK_64(UPLO, [TRANSA], [N], [K], ALPHA, A, [LDA], BETA,
C, [LDC])
CHARACTER(LEN=1) :: UPLO, TRANSA
COMPLEX(8), DIMENSION(:,:) :: A, C
INTEGER(8) :: N, K, LDA, LDC
REAL(8) :: ALPHA, BETA
C INTERFACE
#include <sunperf.h>
void zherk(char uplo, char transa, int n, int k, double alpha, double‐
complex *a, int lda, double beta, doublecomplex *c, int ldc);
void zherk_64(char uplo, char transa, long n, long k, double alpha,
doublecomplex *a, long lda, double beta, doublecomplex *c,
long ldc);
PURPOSEzherk performs one of the Hermitian rank k operations C :=
alpha*A*conjg( A' ) + beta*C or C := alpha*conjg( A' )*A + beta*C where
alpha and beta are real scalars, C is an n by n Hermitian matrix
and A is an n by k matrix in the first case and a k by n matrix
in the second case.
ARGUMENTS
UPLO (input)
On entry, UPLO specifies whether the upper or lower
triangular part of the array C is to be referenced as
follows:
UPLO = 'U' or 'u' Only the upper triangular part of C is
to be referenced.
UPLO = 'L' or 'l' Only the lower triangular part of C is
to be referenced.
Unchanged on exit.
TRANSA (input)
On entry, TRANSA specifies the operation to be performed as
follows:
TRANSA = 'N' or 'n' C := alpha*A*conjg( A' ) + beta*C.
TRANSA = 'C' or 'c' C := alpha*conjg( A' )*A + beta*C.
Unchanged on exit.
TRANSA is defaulted to 'N' for F95 INTERFACE.
N (input)
On entry, N specifies the order of the matrix C. N must be
at least zero. Unchanged on exit.
K (input)
On entry with TRANSA = 'N' or 'n', K specifies the number
of columns of the matrix A, and on entry with
TRANSA = 'C' or 'c', K specifies the number of rows of the
matrix A. K must be at least zero. Unchanged on exit.
ALPHA (input)
On entry, ALPHA specifies the scalar alpha. Unchanged on
exit.
A (input)
COMPLEX*16 array of DIMENSION ( LDA, ka ), where ka is
k when TRANSA = 'N' or 'n', and is n otherwise. Before
entry with TRANSA = 'N' or 'n', the leading n by k part
of the array A must contain the matrix A, otherwise the
leading k by n part of the array A must contain the
matrix A. Unchanged on exit.
LDA (input)
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, n ), otherwise LDA must
be at least max( 1, k ). Unchanged on exit.
BETA (input)
On entry, BETA specifies the scalar beta. Unchanged on exit.
C (input/output)
COMPLEX*16 array of DIMENSION ( LDC, n ).
Before entry with UPLO = 'U' or 'u', the leading n by n
upper triangular part of the array C must contain the upper
triangular part of the Hermitian matrix and the strictly
lower triangular part of C is not referenced. On exit, the
upper triangular part of the array C is overwritten by the
upper triangular part of the updated matrix.
Before entry with UPLO = 'L' or 'l', the leading n by n
lower triangular part of the array C must contain the lower
triangular part of the Hermitian matrix and the strictly
upper triangular part of C is not referenced. On exit, the
lower triangular part of the array C is overwritten by the
lower triangular part of the updated matrix.
Note that the imaginary parts of the diagonal elements need
not be set, they are assumed to be zero, and on exit they
are set to zero.
LDC (input)
On entry, LDC specifies the first dimension of C as declared
in the calling (sub) program. LDC must be at least
max( 1, n ). Unchanged on exit.
6 Mar 2009 zherk(3P)
