Previous: zsymv Up: ../lapack-z.html Next: zsyrfs

NAME ZSYR - perform the symmetric rank 1 operation A := alpha*x*( x' ) + A, SYNOPSIS SUBROUTINE ZSYR( UPLO, N, ALPHA, X, INCX, A, LDA ) CHARACTER UPLO INTEGER INCX, LDA, N COMPLEX*16 ALPHA COMPLEX*16 A( LDA, * ), X( * ) PURPOSE ZSYR performs the symmetric rank 1 operation 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*16 On entry, ALPHA specifies the scalar alpha. Unchanged on exit. X - COMPLEX*16 array, dimension at least ( 1 + ( N - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the N- element vec- tor 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. A - COMPLEX*16 array, dimension( LDA, N ) Before entry with UPLO = 'U' or 'u', the leading n by n upper triangular part of the array A must con- tain 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 tri- angular 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.