org.netlib.lapack
Class Slarrf

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

public class Slarrf
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 ), 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, int _d_offset, float[] l, int _l_offset, float[] ld, int _ld_offset, float[] lld, int _lld_offset, int ifirst, int ilast, float[] w, int _w_offset, float[] dplus, int _dplus_offset, float[] lplus, int _lplus_offset, float[] 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

Slarrf

public Slarrf()
Method Detail

slarrf

public static void slarrf(int n,
                          float[] d,
                          int _d_offset,
                          float[] l,
                          int _l_offset,
                          float[] ld,
                          int _ld_offset,
                          float[] lld,
                          int _lld_offset,
                          int ifirst,
                          int ilast,
                          float[] w,
                          int _w_offset,
                          float[] dplus,
                          int _dplus_offset,
                          float[] lplus,
                          int _lplus_offset,
                          float[] work,
                          int _work_offset,
                          int[] iwork,
                          int _iwork_offset,
                          intW info)