org.netlib.lapack
Class Dstein

java.lang.Object
  org.netlib.lapack.Dstein

public class Dstein
extends java.lang.Object

Following is the description from the original
Fortran source.  For each array argument, the Java
version will include an integer offset parameter, so
the arguments may not match the description exactly.
Contact seymour@cs.utk.edu with any questions.


 *     ..
 *
 *  Purpose
 *  =======
 *
 *  DSTEIN computes the eigenvectors of a real symmetric tridiagonal
 *  matrix T corresponding to specified eigenvalues, using inverse
 *  iteration.
 *
 *  The maximum number of iterations allowed for each eigenvector is
 *  specified by an internal parameter MAXITS (currently set to 5).
 *
 *  Arguments
 *  =========
 *
 *  N       (input) INTEGER
 *          The order of the matrix.  N >= 0.
 *
 *  D       (input) DOUBLE PRECISION array, dimension (N)
 *          The n diagonal elements of the tridiagonal matrix T.
 *
 *  E       (input) DOUBLE PRECISION array, dimension (N)
 *          The (n-1) subdiagonal elements of the tridiagonal matrix
 *          T, in elements 1 to N-1.  E(N) need not be set.
 *
 *  M       (input) INTEGER
 *          The number of eigenvectors to be found.  0 <= M <= N.
 *
 *  W       (input) DOUBLE PRECISION array, dimension (N)
 *          The first M elements of W contain the eigenvalues for
 *          which eigenvectors are to be computed.  The eigenvalues
 *          should be grouped by split-off block and ordered from
 *          smallest to largest within the block.  ( The output array
 *          W from DSTEBZ with ORDER = 'B' is expected here. )
 *
 *  IBLOCK  (input) INTEGER array, dimension (N)
 *          The submatrix indices associated with the corresponding
 *          eigenvalues in W; IBLOCK(i)=1 if eigenvalue W(i) belongs to
 *          the first submatrix from the top, =2 if W(i) belongs to
 *          the second submatrix, etc.  ( The output array IBLOCK
 *          from DSTEBZ is expected here. )
 *
 *  ISPLIT  (input) INTEGER array, dimension (N)
 *          The splitting points, at which T breaks up into submatrices.

 *          The first submatrix consists of rows/columns 1 to
 *          ISPLIT( 1 ), the second of rows/columns ISPLIT( 1 )+1
 *          through ISPLIT( 2 ), etc.
 *          ( The output array ISPLIT from DSTEBZ is expected here. )
 *
 *  Z       (output) DOUBLE PRECISION array, dimension (LDZ, M)
 *          The computed eigenvectors.  The eigenvector associated
 *          with the eigenvalue W(i) is stored in the i-th column of
 *          Z.  Any vector which fails to converge is set to its current

 *          iterate after MAXITS iterations.
 *
 *  LDZ     (input) INTEGER
 *          The leading dimension of the array Z.  LDZ >= max(1,N).
 *
 *  WORK    (workspace) DOUBLE PRECISION array, dimension (5*N)
 *
 *  IWORK   (workspace) INTEGER array, dimension (N)
 *
 *  IFAIL   (output) INTEGER array, dimension (M)
 *          On normal exit, all elements of IFAIL are zero.
 *          If one or more eigenvectors fail to converge after
 *          MAXITS iterations, then their indices are stored in
 *          array IFAIL.
 *
 *  INFO    (output) INTEGER
 *          = 0: successful exit.
 *          < 0: if INFO = -i, the i-th argument had an illegal value
 *          > 0: if INFO = i, then i eigenvectors failed to converge
 *               in MAXITS iterations.  Their indices are stored in
 *               array IFAIL.
 *
 *  Internal Parameters
 *  ===================
 *
 *  MAXITS  INTEGER, default = 5
 *          The maximum number of iterations performed.
 *
 *  EXTRA   INTEGER, default = 2
 *          The number of iterations performed after norm growth
 *          criterion is satisfied, should be at least 1.
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

Dstein()

Method Summary

static void

dstein(int n, double[] d, int _d_offset, double[] e, int _e_offset, int m, double[] w, int _w_offset, int[] iblock, int _iblock_offset, int[] isplit, int _isplit_offset, double[] z, int _z_offset, int ldz, double[] work, int _work_offset, int[] iwork, int _iwork_offset, int[] ifail, int _ifail_offset, intW info)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Dstein

public Dstein()

Method Detail

dstein

public static void dstein(int n,
                          double[] d,
                          int _d_offset,
                          double[] e,
                          int _e_offset,
                          int m,
                          double[] w,
                          int _w_offset,
                          int[] iblock,
                          int _iblock_offset,
                          int[] isplit,
                          int _isplit_offset,
                          double[] z,
                          int _z_offset,
                          int ldz,
                          double[] work,
                          int _work_offset,
                          int[] iwork,
                          int _iwork_offset,
                          int[] ifail,
                          int _ifail_offset,
                          intW info)