Contents
chpr2 - perform the Hermitian rank 2 operation A :=
alpha*x*conjg( y' ) + conjg( alpha )*y*conjg( x' ) + A
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, complex *y, int incy, complex *ap);
void chpr2_64(char uplo, long n, complex *alpha, complex *x,
long incx, complex *y, long incy, complex *ap);
chpr2 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.
UPLO (input)
On entry, UPLO specifies whether the upper or
lower triangular 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 supplied in AP.
UPLO = 'L' or 'l' The lower triangular part of A
is supplied 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 hermitian
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.