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Technical Reference: Base Operating System and Extensions , Volume 2
Performs the Hermitian rank 1
operation.
BLAS Library
(libblas.a)
SUBROUTINE CHER(UPLO, N, ALPHA,
X, INCX, A, LDA)
REAL ALPHA
INTEGER INCX, LDA, N
CHARACTER*1 UPLO
COMPLEX A(LDA,*), X(*)
SUBROUTINE ZHER(UPLO, N, ALPHA,
X, INCX, A, LDA)
DOUBLE PRECISION ALPHA
INTEGER INCX,LDA,N
CHARACTER*1 UPLO
COMPLEX*16 A(LDA,*), X(*)
The CHER or
ZHER subroutine performs the Hermitian rank 1 operation:
A := alpha
* x * conjg( x' ) + A
where alpha is a real scalar, x
is an N element vector and A is an N by
N Hermitian matrix.
UPLO
 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
 On entry, N specifies the order of the matrix
A; N must be at least 0; unchanged on
exit.

ALPHA
 On entry, ALPHA specifies the scalar alpha; unchanged on
exit.

X
 A vector of dimension at least (1 + (N1) *
abs(INCX) ); on entry, the incremented array X must
contain the N element vector x; unchanged on exit.

INCX
 On entry, INCX specifies the increment for the elements of
X; INCX must not be 0; unchanged on
exit.

A
 An array of dimension ( LDA, N ); on 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 Hermitian 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. On 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 Hermitian 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. The imaginary parts of the
diagonal elements need not be set, they are assumed to be 0, and on exit they
are set to 0.

LDA
 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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