org.netlib.lapack
Class SLARRB

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

public class SLARRB
extends java.lang.Object

SLARRB is a simplified interface to the JLAPACK routine slarrb.
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 relatively robust representation(RRR) L D L^T, SLARRB * does ``limited'' bisection to locate the eigenvalues of L D L^T, * W( IFIRST ) thru' W( ILAST ), to more accuracy. Intervals * [left, right] are maintained by storing their mid-points and * semi-widths in the arrays W and WERR respectively. * * 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. * * SIGMA (input) REAL * The shift used to form L D L^T (see SLARRF). * * RELTOL (input) REAL * The relative tolerance. * * W (input/output) REAL array, dimension (N) * On input, W( IFIRST ) thru' W( ILAST ) are estimates of the * corresponding eigenvalues of L D L^T. * On output, these estimates are ``refined''. * * WGAP (input/output) REAL array, dimension (N) * The gaps between the eigenvalues of L D L^T. Very small * gaps are changed on output. * * WERR (input/output) REAL array, dimension (N) * On input, WERR( IFIRST ) thru' WERR( ILAST ) are the errors * in the estimates W( IFIRST ) thru' W( ILAST ). * On output, these are the ``refined'' errors. * *****Reminder to Inder --- WORK is never used in this subroutine ***** * WORK (input) REAL array, dimension (???) * Workspace. * * IWORK (input) INTEGER array, dimension (2*N) * Workspace. * *****Reminder to Inder --- INFO is never set in this subroutine ****** * INFO (output) INTEGER * Error flag. * * Further Details * =============== * * Based on contributions by * Inderjit Dhillon, IBM Almaden, USA * Osni Marques, LBNL/NERSC, USA * * ===================================================================== * * .. Parameters ..


Constructor Summary
SLARRB()
           
 
Method Summary
static void SLARRB(int n, float[] d, float[] l, float[] ld, float[] lld, int ifirst, int ilast, float sigma, float reltol, float[] w, float[] wgap, float[] werr, float[] work, int[] iwork, int info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SLARRB

public SLARRB()
Method Detail

SLARRB

public static void SLARRB(int n,
                          float[] d,
                          float[] l,
                          float[] ld,
                          float[] lld,
                          int ifirst,
                          int ilast,
                          float sigma,
                          float reltol,
                          float[] w,
                          float[] wgap,
                          float[] werr,
                          float[] work,
                          int[] iwork,
                          int info)