org.netlib.lapack
Class SLARRF

java.lang.Object
  org.netlib.lapack.SLARRF

public class SLARRF
extends java.lang.Object

SLARRF is a simplified interface to the JLAPACK routine slarrf.
This interface converts Java-style 2D row-major arrays into
the 1D column-major linearized arrays expected by the lower
level JLAPACK routines.  Using this interface also allows you
to omit offset and leading dimension arguments.  However, because
of these conversions, these routines will be slower than the low
level ones.  Following is the description from the original Fortran
source.  Contact seymour@cs.utk.edu with any questions.

 *     ..
 *
 *  Purpose
 *  =======
 *
 *  Given the initial representation L D L^T and its cluster of close
 *  eigenvalues (in a relative measure), W( IFIRST ), W( IFIRST+1 ), ...

 *  W( ILAST ), SLARRF finds a new relatively robust representation
 *  L D L^T - SIGMA I = L(+) D(+) L(+)^T such that at least one of the
 *  eigenvalues of L(+) D(+) L(+)^T is relatively isolated.
 *
 *  Arguments
 *  =========
 *
 *  N       (input) INTEGER
 *          The order of the matrix.
 *
 *  D       (input) REAL array, dimension (N)
 *          The n diagonal elements of the diagonal matrix D.
 *
 *  L       (input) REAL array, dimension (N-1)
 *          The (n-1) subdiagonal elements of the unit bidiagonal
 *          matrix L.
 *
 *  LD      (input) REAL array, dimension (N-1)
 *          The n-1 elements L(i)*D(i).
 *
 *  LLD     (input) REAL array, dimension (N-1)
 *          The n-1 elements L(i)*L(i)*D(i).
 *
 *  IFIRST  (input) INTEGER
 *          The index of the first eigenvalue in the cluster.
 *
 *  ILAST   (input) INTEGER
 *          The index of the last eigenvalue in the cluster.
 *
 *  W       (input/output) REAL array, dimension (N)
 *          On input, the eigenvalues of L D L^T in ascending order.
 *          W( IFIRST ) through W( ILAST ) form the cluster of relatively
 *          close eigenalues.
 *          On output, W( IFIRST ) thru' W( ILAST ) are estimates of the

 *          corresponding eigenvalues of L(+) D(+) L(+)^T.
 *
 *  SIGMA   (input) REAL
 *          The shift used to form L(+) D(+) L(+)^T.
 *
 *  DPLUS   (output) REAL array, dimension (N)
 *          The n diagonal elements of the diagonal matrix D(+).
 *
 *  LPLUS   (output) REAL array, dimension (N)
 *          The first (n-1) elements of LPLUS contain the subdiagonal
 *          elements of the unit bidiagonal matrix L(+). LPLUS( N ) is
 *          set to SIGMA.
 *
 *  WORK    (input) REAL array, dimension (???)
 *          Workspace.
 *
 *  Further Details
 *  ===============
 *
 *  Based on contributions by
 *     Inderjit Dhillon, IBM Almaden, USA
 *     Osni Marques, LBNL/NERSC, USA
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

SLARRF()

Method Summary

static void

SLARRF(int n, float[] d, float[] l, float[] ld, float[] lld, int ifirst, int ilast, float[] w, float[] dplus, float[] lplus, float[] work, int[] iwork, intW info)

Methods inherited from class java.lang.Object

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

Constructor Detail

SLARRF

public SLARRF()

Method Detail

SLARRF

public static void SLARRF(int n,
                          float[] d,
                          float[] l,
                          float[] ld,
                          float[] lld,
                          int ifirst,
                          int ilast,
                          float[] w,
                          float[] dplus,
                          float[] lplus,
                          float[] work,
                          int[] iwork,
                          intW info)