CSYR - perform the symmetric rank 1 operation A :=
alpha*x*( x' ) + A,
SYNOPSIS
SUBROUTINE CSYR( UPLO, N, ALPHA, X, INCX, A, LDA )
CHARACTER UPLO
INTEGER INCX, LDA, N
COMPLEX ALPHA
COMPLEX A( LDA, * ), X( * )
PURPOSE
CSYR performs the symmetric rank 1 operation A :=
alpha*x*( x' ) + A, where alpha is a complex scalar, x is
an n element vector and A is an n by n symmetric matrix.
ARGUMENTS
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 - COMPLEX
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit.
X - COMPLEX array, 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 ele
ments of X. INCX must not be zero. Unchanged on
exit.
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.
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