org.netlib.lapack
Class DLARRF

java.lang.Object
  extended by 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( CLSTRT ), W( CLSTRT+1 ), ... * W( CLEND ), 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 (subblock, if the matrix splitted). * * 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). * * CLSTRT (input) INTEGER * The index of the first eigenvalue in the cluster. * * CLEND (input) INTEGER * The index of the last eigenvalue in the cluster. * * W (input) DOUBLE PRECISION array, dimension >= (CLEND-CLSTRT+1 * The eigenvalue APPROXIMATIONS of L D L^T in ascending order. * W( CLSTRT ) through W( CLEND ) form the cluster of relatively * close eigenalues. * * WGAP (input/output) DOUBLE PRECISION array, dimension >= (CLEND-C * The separation from the right neighbor eigenvalue in W. * * WERR (input) DOUBLE PRECISION array, dimension >= (CLEND-CLSTRT+1 * WERR contain the semiwidth of the uncertainty * interval of the corresponding eigenvalue APPROXIMATION in W * * SPDIAM (input) estimate of the spectral diameter obtained from the * Gerschgorin intervals * * CLGAPL, CLGAPR (input) absolute gap on each end of the cluster. * Set by the calling routine to protect against shifts too clos * to eigenvalues outside the cluster. * * PIVMIN (input) DOUBLE PRECISION * The minimum pivot allowed in the Sturm sequence. * * SIGMA (output) 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-1) * The first (N-1) elements of LPLUS contain the subdiagonal * elements of the unit bidiagonal matrix L(+). * * WORK (workspace) DOUBLE PRECISION array, dimension (2*N) * Workspace. * * Further Details * =============== * * Based on contributions by * Beresford Parlett, University of California, Berkeley, USA * Jim Demmel, University of California, Berkeley, USA * Inderjit Dhillon, University of Texas, Austin, USA * Osni Marques, LBNL/NERSC, USA * Christof Voemel, University of California, Berkeley, USA * * ===================================================================== * * .. Parameters ..


Constructor Summary
DLARRF()
           
 
Method Summary
static void DLARRF(int n, double[] d, double[] l, double[] ld, int clstrt, int clend, double[] w, double[] wgap, double[] werr, double spdiam, double clgapl, double clgapr, double pivmin, doubleW sigma, double[] dplus, double[] lplus, double[] work, 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,
                          int clstrt,
                          int clend,
                          double[] w,
                          double[] wgap,
                          double[] werr,
                          double spdiam,
                          double clgapl,
                          double clgapr,
                          double pivmin,
                          doubleW sigma,
                          double[] dplus,
                          double[] lplus,
                          double[] work,
                          intW info)