org.netlib.lapack
Class DLARRF

java.lang.Object
  org.netlib.lapack.DLARRF

public class DLARRF
extends java.lang.Object

DLARRF is a simplified interface to the JLAPACK routine dlarrf.
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 ), DLARRF 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) DOUBLE PRECISION array, dimension (N)
 *          The n diagonal elements of the diagonal matrix D.
 *
 *  L       (input) DOUBLE PRECISION array, dimension (N-1)
 *          The (n-1) subdiagonal elements of the unit bidiagonal
 *          matrix L.
 *
 *  LD      (input) DOUBLE PRECISION array, dimension (N-1)
 *          The n-1 elements L(i)*D(i).
 *
 *  LLD     (input) DOUBLE PRECISION 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) DOUBLE PRECISION 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) DOUBLE PRECISION
 *          The shift used to form L(+) D(+) L(+)^T.
 *
 *  DPLUS   (output) DOUBLE PRECISION array, dimension (N)
 *          The n diagonal elements of the diagonal matrix D(+).
 *
 *  LPLUS   (output) DOUBLE PRECISION 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) DOUBLE PRECISION array, dimension (???)
 *          Workspace.
 *
 *  Further Details
 *  ===============
 *
 *  Based on contributions by
 *     Inderjit Dhillon, IBM Almaden, USA
 *     Osni Marques, LBNL/NERSC, USA
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

DLARRF()

Method Summary

static void

DLARRF(int n, double[] d, double[] l, double[] ld, double[] lld, int ifirst, int ilast, double[] w, double[] dplus, double[] lplus, double[] 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

DLARRF

public DLARRF()

Method Detail

DLARRF

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