The OpenNET Project / Index page

[ новости /+++ | форум | теги | ]

Интерактивная система просмотра системных руководств (man-ов)

 ТемаНаборКатегория 
 
 [Cписок руководств | Печать]

dsteqr (3)
  • >> dsteqr (3) ( Solaris man: Библиотечные вызовы )
  • 
    NAME
         dsteqr - compute all eigenvalues and, optionally,  eigenvec-
         tors of a symmetric tridiagonal matrix using the implicit QL
         or QR method
    
    SYNOPSIS
         SUBROUTINE DSTEQR( COMPZ, N, D, E, Z, LDZ, WORK, INFO )
    
         CHARACTER COMPZ
    
         INTEGER INFO, LDZ, N
    
         DOUBLE PRECISION D( * ), E( * ), WORK( * ), Z( LDZ, * )
    
    
    
         #include <sunperf.h>
    
         void dsteqr(char compz, int n, double *d, double *e,  double
                   *dz, int ldz, int *info) ;
    
    PURPOSE
         DSTEQR computes all eigenvalues and,  optionally,  eigenvec-
         tors of a symmetric tridiagonal matrix using the implicit QL
         or QR method.  The eigenvectors of a full or band  symmetric
         matrix  can  also be found if DSYTRD or DSPTRD or DSBTRD has
         been used to reduce this matrix to tridiagonal form.
    
    
    ARGUMENTS
         COMPZ     (input) CHARACTER*1
                   = 'N':  Compute eigenvalues only.
                   = 'V':  Compute eigenvalues  and  eigenvectors  of
                   the  original  symmetric matrix.  On entry, Z must
                   contain the orthogonal matrix used to  reduce  the
                   original matrix to tridiagonal form.  = 'I':  Com-
                   pute eigenvalues and eigenvectors of the tridiago-
                   nal  matrix.   Z  is  initialized  to the identity
                   matrix.
    
         N         (input) INTEGER
                   The order of the matrix.  N >= 0.
    
         D         (input/output) DOUBLE PRECISION  array,  dimension
                   (N)
                   On entry, the diagonal elements of the tridiagonal
                   matrix.   On exit, if INFO = 0, the eigenvalues in
                   ascending order.
    
         E         (input/output) DOUBLE PRECISION  array,  dimension
                   (N-1)
                   On entry, the (n-1) subdiagonal  elements  of  the
                   tridiagonal  matrix.   On  exit,  E  has been des-
                   troyed.
    
         Z         (input/output) DOUBLE PRECISION  array,  dimension
                   (LDZ, N)
                   On entry, if  COMPZ = 'V',  then  Z  contains  the
                   orthogonal  matrix used in the reduction to tridi-
                   agonal form.  On exit, if INFO = 0, then if  COMPZ
                   =  'V', Z contains the orthonormal eigenvectors of
                   the original symmetric matrix, and if COMPZ = 'I',
                   Z  contains  the  orthonormal  eigenvectors of the
                   symmetric tridiagonal matrix.   If  COMPZ  =  'N',
                   then Z is not referenced.
    
         LDZ       (input) INTEGER
                   The leading dimension of the array Z.  LDZ  >=  1,
                   and  if  eigenvectors  are  desired,  then  LDZ >=
                   max(1,N).
    
         WORK      (workspace)  DOUBLE  PRECISION  array,   dimension
                   (max(1,2*N-2))
                   If COMPZ = 'N', then WORK is not referenced.
    
         INFO      (output) INTEGER
                   = 0:  successful exit
                   < 0:  if INFO = -i, the i-th argument had an ille-
                   gal value
                   > 0:  the algorithm has failed  to  find  all  the
                   eigenvalues in a total of 30*N iterations; if INFO
                   = i, then i elements of E have  not  converged  to
                   zero;  on  exit, D and E contain the elements of a
                   symmetric tridiagonal matrix which is orthogonally
                   similar to the original matrix.
    
    
    
    


    Поиск по тексту MAN-ов: 




    Партнёры:
    PostgresPro
    Inferno Solutions
    Hosting by Hoster.ru
    Хостинг:

    Закладки на сайте
    Проследить за страницей
    Created 1996-2024 by Maxim Chirkov
    Добавить, Поддержать, Вебмастеру