org.netlib.lapack
Class Dlarrf

java.lang.Object
  extended by org.netlib.lapack.Dlarrf

public class Dlarrf
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 * ======= * * 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, int _d_offset, double[] l, int _l_offset, double[] ld, int _ld_offset, double[] lld, int _lld_offset, int ifirst, int ilast, double[] w, int _w_offset, double[] dplus, int _dplus_offset, double[] lplus, int _lplus_offset, double[] work, int _work_offset, int[] iwork, int _iwork_offset, 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,
                          int _d_offset,
                          double[] l,
                          int _l_offset,
                          double[] ld,
                          int _ld_offset,
                          double[] lld,
                          int _lld_offset,
                          int ifirst,
                          int ilast,
                          double[] w,
                          int _w_offset,
                          double[] dplus,
                          int _dplus_offset,
                          double[] lplus,
                          int _lplus_offset,
                          double[] work,
                          int _work_offset,
                          int[] iwork,
                          int _iwork_offset,
                          intW info)