dspr(3P) Sun Performance Library dspr(3P)NAMEdspr - perform the symmetric rank 1 operation A := alpha*x*x' + A
SYNOPSIS
SUBROUTINE DSPR(UPLO, N, ALPHA, X, INCX, A)
CHARACTER * 1 UPLO
INTEGER N, INCX
DOUBLE PRECISION ALPHA
DOUBLE PRECISION X(*), A(*)
SUBROUTINE DSPR_64(UPLO, N, ALPHA, X, INCX, A)
CHARACTER * 1 UPLO
INTEGER*8 N, INCX
DOUBLE PRECISION ALPHA
DOUBLE PRECISION X(*), A(*)
F95 INTERFACE
SUBROUTINE SPR(UPLO, N, ALPHA, X, [INCX], A)
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, INCX
REAL(8) :: ALPHA
REAL(8), DIMENSION(:) :: X, A
SUBROUTINE SPR_64(UPLO, N, ALPHA, X, [INCX], A)
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, INCX
REAL(8) :: ALPHA
REAL(8), DIMENSION(:) :: X, A
C INTERFACE
#include <sunperf.h>
void dspr(char uplo, int n, double alpha, double *x, int incx, double
*a);
void dspr_64(char uplo, long n, double alpha, double *x, long incx,
double *a);
PURPOSEdspr performs the symmetric rank 1 operation A := alpha*x*x' + A, where
alpha is a real scalar, x is an n element vector 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 A.
UPLO = 'L' or 'l' The lower triangular part of A is sup‐
plied in A.
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.
A (input/output)
( ( n*( n + 1 ) )/2 ). Before entry with UPLO = 'U' or 'u',
the array A must contain the upper triangular part of the
symmetric matrix packed sequentially, column by column, so
that A( 1 ) contains a( 1, 1 ), A( 2 ) and A( 3 ) contain a(
1, 2 ) and a( 2, 2 ) respectively, and so on. On exit, the
array A is overwritten by the upper triangular part of the
updated matrix. Before entry with UPLO = 'L' or 'l', the
array A must contain the lower triangular part of the symmet‐
ric matrix packed sequentially, column by column, so that A(
1 ) contains a( 1, 1 ), A( 2 ) and A( 3 ) contain a( 2, 1 )
and a( 3, 1 ) respectively, and so on. On exit, the array A
is overwritten by the lower triangular part of the updated
matrix.
6 Mar 2009 dspr(3P)
