sspr2(3P) Sun Performance Library sspr2(3P)NAMEsspr2 - perform the symmetric rank 2 operation A := alpha*x*y' +
alpha*y*x' + A
SYNOPSIS
SUBROUTINE SSPR2(UPLO, N, ALPHA, X, INCX, Y, INCY, AP)
CHARACTER * 1 UPLO
INTEGER N, INCX, INCY
REAL ALPHA
REAL X(*), Y(*), AP(*)
SUBROUTINE SSPR2_64(UPLO, N, ALPHA, X, INCX, Y, INCY, AP)
CHARACTER * 1 UPLO
INTEGER*8 N, INCX, INCY
REAL ALPHA
REAL X(*), Y(*), AP(*)
F95 INTERFACE
SUBROUTINE SPR2(UPLO, [N], ALPHA, X, [INCX], Y, [INCY], AP)
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, INCX, INCY
REAL :: ALPHA
REAL, DIMENSION(:) :: X, Y, AP
SUBROUTINE SPR2_64(UPLO, [N], ALPHA, X, [INCX], Y, [INCY], AP)
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, INCX, INCY
REAL :: ALPHA
REAL, DIMENSION(:) :: X, Y, AP
C INTERFACE
#include <sunperf.h>
void sspr2(char uplo, int n, float alpha, float *x, int incx, float *y,
int incy, float *ap);
void sspr2_64(char uplo, long n, float alpha, float *x, long incx,
float *y, long incy, float *ap);
PURPOSEsspr2 performs the symmetric rank 2 operation A := alpha*x*y' +
alpha*y*x' + A, where alpha is a scalar, x and y are n element vectors
and A is an n by n symmetric 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 A 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)
Real array, dimension (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)
Real array, dimension (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)
Real array, dimension (( n*(n + 1))/2) Before entry with
UPLO = 'U' or 'u', the array AP must contain the upper trian‐
gular part of the symmetric matrix packed sequentially, col‐
umn 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 A is overwritten by the upper tri‐
angular part of the updated matrix. Before entry with UPLO =
'L' or 'l', the array AP must contain the lower triangular
part of the symmetric 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.
6 Mar 2009 sspr2(3P)
