csymv (l) - Linux Manuals

csymv: performs the matrix-vector operation y := alpha*A*x + beta*y,

NAME

CSYMV - performs the matrix-vector operation y := alpha*A*x + beta*y,

SYNOPSIS

SUBROUTINE CSYMV(
UPLO, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY )

    
CHARACTER UPLO

    
INTEGER INCX, INCY, LDA, N

    
COMPLEX ALPHA, BETA

    
COMPLEX A( LDA, * ), X( * ), Y( * )

PURPOSE

CSYMV performs the matrix-vector operation where alpha and beta are scalars, x and y are n element vectors and A is an n by n symmetric matrix.

ARGUMENTS

UPLO (input) CHARACTER*1
On entry, UPLO specifies whether the upper or lower triangular part of the array A is to be referenced as follows: UPLO = aqUaq or aquaq Only the upper triangular part of A is to be referenced. UPLO = aqLaq or aqlaq Only the lower triangular part of A is to be referenced. Unchanged on exit.
N (input) INTEGER
On entry, N specifies the order of the matrix A. N must be at least zero. Unchanged on exit.
ALPHA (input) COMPLEX
On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
A (input) COMPLEX array, dimension ( LDA, N )
Before entry, with UPLO = aqUaq or aquaq, 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. Before entry, with UPLO = aqLaq or aqlaq, 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. Unchanged on exit.
LDA (input) 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.
X (input) 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 (input) INTEGER
On entry, INCX specifies the increment for the elements of X. INCX must not be zero. Unchanged on exit.
BETA (input) COMPLEX
On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input. Unchanged on exit.
Y (input/output) COMPLEX array, dimension at least
( 1 + ( N - 1 )*abs( INCY ) ). Before entry, the incremented array Y must contain the n element vector y. On exit, Y is overwritten by the updated vector y.
INCY (input) INTEGER
On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Unchanged on exit.

Pages related to csymv

  • csymv (3)
  • csymm (l) - performs one of the matrix-matrix operations C := alpha*A*B + beta*C,
  • csycon (l) - estimates the reciprocal of the condition number (in the 1-norm) of a complex symmetric matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by CSYTRF
  • csyequb (l) - computes row and column scalings intended to equilibrate a symmetric matrix A and reduce its condition number (with respect to the two-norm)
  • csyr (l) - performs the symmetric rank 1 operation A := alpha*x*( xaq ) + A,
  • csyr2k (l) - performs one of the symmetric rank 2k operations C := alpha*A*Baq + alpha*B*Aaq + beta*C,
  • csyrfs (l) - improves the computed solution to a system of linear equations when the coefficient matrix is symmetric indefinite, and provides error bounds and backward error estimates for the solution
  • csyrfsx (l) - CSYRFSX improve the computed solution to a system of linear equations when the coefficient matrix is symmetric indefinite, and provides error bounds and backward error estimates for the solution
  • csyrk (l) - performs one of the symmetric rank k operations C := alpha*A*Aaq + beta*C,