Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages

RedHat 9 (Linux i386) - man page for dspev (redhat section l)

DSPEV(l)					)					 DSPEV(l)

NAME
       DSPEV  -  compute  all  the  eigenvalues and, optionally, eigenvectors of a real symmetric
       matrix A in packed storage

SYNOPSIS
       SUBROUTINE DSPEV( JOBZ, UPLO, N, AP, W, Z, LDZ, WORK, INFO )

	   CHARACTER	 JOBZ, UPLO

	   INTEGER	 INFO, LDZ, N

	   DOUBLE	 PRECISION AP( * ), W( * ), WORK( * ), Z( LDZ, * )

PURPOSE
       DSPEV computes all the eigenvalues and,	optionally,  eigenvectors  of  a  real	symmetric
       matrix A in packed storage.

ARGUMENTS
       JOBZ    (input) CHARACTER*1
	       = 'N':  Compute eigenvalues only;
	       = 'V':  Compute eigenvalues and eigenvectors.

       UPLO    (input) CHARACTER*1
	       = 'U':  Upper triangle of A is stored;
	       = 'L':  Lower triangle of A is stored.

       N       (input) INTEGER
	       The order of the matrix A.  N >= 0.

       AP      (input/output) DOUBLE PRECISION array, dimension (N*(N+1)/2)
	       On entry, the upper or lower triangle of the symmetric matrix A, packed columnwise
	       in a linear array.  The j-th column of A is stored in the array AP as follows:  if
	       UPLO  =	'U',  AP(i  +  (j-1)*j/2)  =  A(i,j)  for  1<=i<=j; if UPLO = 'L', AP(i +
	       (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.

	       On exit, AP is overwritten by values generated during the reduction to tridiagonal
	       form.   If  UPLO  =  'U',  the diagonal and first superdiagonal of the tridiagonal
	       matrix T overwrite the corresponding elements of A, and if UPLO = 'L', the  diago-
	       nal and first subdiagonal of T overwrite the corresponding elements of A.

       W       (output) DOUBLE PRECISION array, dimension (N)
	       If INFO = 0, the eigenvalues in ascending order.

       Z       (output) DOUBLE PRECISION array, dimension (LDZ, N)
	       If  JOBZ  =  'V', then if INFO = 0, Z contains the orthonormal eigenvectors of the
	       matrix A, with the i-th column of Z holding the eigenvector associated with  W(i).
	       If JOBZ = 'N', then Z is not referenced.

       LDZ     (input) INTEGER
	       The  leading  dimension	of  the  array	Z.   LDZ  >= 1, and if JOBZ = 'V', LDZ >=
	       max(1,N).

       WORK    (workspace) DOUBLE PRECISION array, dimension (3*N)

       INFO    (output) INTEGER
	       = 0:  successful exit.
	       < 0:  if INFO = -i, the i-th argument had an illegal value.
	       > 0:  if INFO = i, the algorithm failed to converge; i off-diagonal elements of an
	       intermediate tridiagonal form did not converge to zero.

LAPACK version 3.0			   15 June 2000 				 DSPEV(l)


All times are GMT -4. The time now is 05:51 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
UNIX.COM Login
Username:
Password:  
Show Password