Contents
dspr - perform the symmetric rank 1 operation A :=
alpha*x*x' + A
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);
dspr 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.
UPLO (input)
On entry, UPLO specifies whether the upper or
lower triangular 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 supplied in A.
UPLO = 'L' or 'l' The lower triangular part of A
is supplied 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 tri-
angular part of the updated matrix. Before entry
with UPLO = 'L' or 'l', the array A must contain
the lower 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( 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.