NAME
ssyr - perform the symmetric rank 1 operation A :=
alpha*x*x' + A
SYNOPSIS
SUBROUTINE SSYR ( UPLO, N, ALPHA, X, INCX, A, LDA )
REAL ALPHA
INTEGER INCX, LDA, N
CHARACTER*1 UPLO
REAL A( LDA, * ), X( * )
#include <sunperf.h>
void ssyr(char uplo, int n, float alpha, float *sx, int
incx, float *sa, int lda) ;
PURPOSE
SSYR performs the symmetric rank 1 operation A :=
alpha*x*x' + A, where alpha is a real scalar, x is an n ele-
ment vector and A is an n by n symmetric matrix.
PARAMETERS
UPLO - CHARACTER*1.
On entry, UPLO specifies whether the upper or
lower triangular part of the array A is to be
referenced as follows:
UPLO = 'U' or 'u' Only the upper triangular part
of A is to be referenced.
UPLO = 'L' or 'l' Only the lower triangular part
of A is to be referenced.
Unchanged on exit.
N - INTEGER.
On entry, N specifies the order of the matrix A.
N must be at least zero. Unchanged on exit.
ALPHA - REAL .
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit.
X - REAL array of dimension at least
( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the
incremented array X must contain the n element
vector x. Unchanged on exit.
INCX - INTEGER.
On entry, INCX specifies the increment for the
elements of X. INCX must not be zero. Unchanged
on exit.
A - REAL array of DIMENSION ( LDA, n ).
Before entry with UPLO = 'U' or 'u', the leading
n by n upper triangular part of the array A must
contain the upper triangular part of the symmetric
matrix and the strictly lower triangular part of A
is not referenced. On exit, the upper triangular
part of the array A is overwritten by the upper
triangular part of the updated matrix. Before
entry with UPLO = 'L' or 'l', the leading n by n
lower triangular part of the array A must contain
the lower triangular part of the symmetric matrix
and the strictly upper triangular part of A is not
referenced. On exit, the lower triangular part of
the array A is overwritten by the lower triangular
part of the updated matrix.
LDA - INTEGER.
On entry, LDA specifies the first dimension of A
as declared in the calling (sub) program. LDA must
be at least max( 1, n ). Unchanged on exit.
|
Закладки на сайте Проследить за страницей |
Created 1996-2025 by Maxim Chirkov Добавить, Поддержать, Вебмастеру |