chpr2(3P) Sun Performance Library chpr2(3P)NAMEchpr2 - perform the Hermitian rank 2 operation A := alpha*x*conjg( y'
) + conjg( alpha )*y*conjg( x' ) + A
SYNOPSIS
SUBROUTINE CHPR2(UPLO, N, ALPHA, X, INCX, Y, INCY, AP)
CHARACTER * 1 UPLO
COMPLEX ALPHA
COMPLEX X(*), Y(*), AP(*)
INTEGER N, INCX, INCY
SUBROUTINE CHPR2_64(UPLO, N, ALPHA, X, INCX, Y, INCY, AP)
CHARACTER * 1 UPLO
COMPLEX ALPHA
COMPLEX X(*), Y(*), AP(*)
INTEGER*8 N, INCX, INCY
F95 INTERFACE
SUBROUTINE HPR2(UPLO, [N], ALPHA, X, [INCX], Y, [INCY], AP)
CHARACTER(LEN=1) :: UPLO
COMPLEX :: ALPHA
COMPLEX, DIMENSION(:) :: X, Y, AP
INTEGER :: N, INCX, INCY
SUBROUTINE HPR2_64(UPLO, [N], ALPHA, X, [INCX], Y, [INCY], AP)
CHARACTER(LEN=1) :: UPLO
COMPLEX :: ALPHA
COMPLEX, DIMENSION(:) :: X, Y, AP
INTEGER(8) :: N, INCX, INCY
C INTERFACE
#include <sunperf.h>
void chpr2(char uplo, int n, complex *alpha, complex *x, int incx, com‐
plex *y, int incy, complex *ap);
void chpr2_64(char uplo, long n, complex *alpha, complex *x, long incx,
complex *y, long incy, complex *ap);
PURPOSEchpr2 performs the Hermitian rank 2 operation A := alpha*x*conjg( y' )
+ conjg( alpha )*y*conjg( x' ) + A where alpha is a scalar, x and y are
n element vectors and A is an n by n hermitian matrix, supplied in
packed form.
ARGUMENTS
UPLO (input)
On entry, UPLO specifies whether the upper or lower triangu‐
lar part of the matrix A is supplied in the packed array AP
as follows:
UPLO = 'U' or 'u' The upper triangular part of A is sup‐
plied in AP.
UPLO = 'L' or 'l' The lower triangular part of A is sup‐
plied in AP.
Unchanged on exit.
N (input)
On entry, N specifies the order of the matrix A. N >= 0.
Unchanged on exit.
ALPHA (input)
On entry, ALPHA specifies the scalar alpha. Unchanged on
exit.
X (input)
( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented
array X must contain the n element vector x. Unchanged on
exit.
INCX (input)
On entry, INCX specifies the increment for the elements of X.
INCX <> 0. Unchanged on exit.
Y (input)
( 1 + ( n - 1 )*abs( INCY ) ). Before entry, the incremented
array Y must contain the n element vector y. Unchanged on
exit.
INCY (input)
On entry, INCY specifies the increment for the elements of Y.
INCY <> 0. Unchanged on exit.
AP (input/output)
( ( n*( n + 1 ) )/2 ). Before entry with UPLO = 'U' or 'u',
the array AP must contain the upper triangular part of the
hermitian matrix packed sequentially, column by column, so
that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain
a( 1, 2 ) and a( 2, 2 ) respectively, and so on. On exit, the
array AP is overwritten by the upper triangular part of the
updated matrix. Before entry with UPLO = 'L' or 'l', the
array AP must contain the lower triangular part of the her‐
mitian matrix packed sequentially, column by column, so that
AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2,
1 ) and a( 3, 1 ) respectively, and so on. On exit, the array
AP is overwritten by the lower triangular part of the updated
matrix. Note that the imaginary parts of the diagonal ele‐
ments need not be set, they are assumed to be zero, and on
exit they are set to zero.
6 Mar 2009 chpr2(3P)
