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## org.netlib.lapack
Class SLARRB

    java.lang.Object
      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 refine the eigenvalues of L D L^T,
     *  W( IFIRST-OFFSET ) through W( ILAST-OFFSET ), to more accuracy. Initi
     *  guesses for these eigenvalues are input in W, the corresponding estim
     *  of the error in these guesses and their gaps are input in WERR
     *  and WGAP, respectively. During bisection, 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.
     *
     *  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 to be computed.
     *
     *  ILAST   (input) INTEGER
     *          The index of the last eigenvalue to be computed.
     *
     *  RTOL1   (input) REAL
     *  RTOL2   (input) REAL
     *          Tolerance for the convergence of the bisection intervals.
     *          An interval [LEFT,RIGHT] has converged if
     *          RIGHT-LEFT.LT.MAX( RTOL1*GAP, RTOL2*MAX(|LEFT|,|RIGHT|) )
     *          where GAP is the (estimated) distance to the nearest
     *          eigenvalue.
     *
     *  OFFSET  (input) INTEGER
     *          Offset for the arrays W, WGAP and WERR, i.e., the IFIRST-OFFS
     *          through ILAST-OFFSET elements of these arrays are to be used.
     *
     *  W       (input/output) REAL             array, dimension (N)
     *          On input, W( IFIRST-OFFSET ) through W( ILAST-OFFSET ) are
     *          estimates of the eigenvalues of L D L^T indexed IFIRST throug
     *          ILAST.
     *          On output, these estimates are refined.
     *
     *  WGAP    (input/output) REAL             array, dimension (N-1)
     *          On input, the (estimated) gaps between consecutive
     *          eigenvalues of L D L^T, i.e., WGAP(I-OFFSET) is the gap betwe
     *          eigenvalues I and I+1. Note that if IFIRST.EQ.ILAST
     *          then WGAP(IFIRST-OFFSET) must be set to ZERO.
     *          On output, these gaps are refined.
     *
     *  WERR    (input/output) REAL             array, dimension (N)
     *          On input, WERR( IFIRST-OFFSET ) through WERR( ILAST-OFFSET )
     *          the errors in the estimates of the corresponding elements in
     *          On output, these errors are refined.
     *
     *  WORK    (workspace) REAL             array, dimension (2*N)
     *          Workspace.
     *
     *  IWORK   (workspace) INTEGER array, dimension (2*N)
     *          Workspace.
     *
     *  PIVMIN  (input) DOUBLE PRECISION
     *          The minimum pivot in the Sturm sequence.
     *
     *  SPDIAM  (input) DOUBLE PRECISION
     *          The spectral diameter of the matrix.
     *
     *  TWIST   (input) INTEGER
     *          The twist index for the twisted factorization that is used
     *          for the negcount.
     *          TWIST = N: Compute negcount from L D L^T - LAMBDA I = L+ D+ L
     *          TWIST = 1: Compute negcount from L D L^T - LAMBDA I = U- D- U
     *          TWIST = R: Compute negcount from L D L^T - LAMBDA I = N(r) D(
     *
     *  INFO    (output) INTEGER
     *          Error flag.
     *
     *  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
`SLARRB()`

Method Summary
`static void` | `SLARRB(int n, float[] d, float[] lld, int ifirst, int ilast, float rtol1, float rtol2, int offset, float[] w, float[] wgap, float[] werr, float[] work, int[] iwork, float pivmin, float spdiam, int twist, intW 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[] lld,
                              int ifirst,
                              int ilast,
                              float rtol1,
                              float rtol2,
                              int offset,
                              float[] w,
                              float[] wgap,
                              float[] werr,
                              float[] work,
                              int[] iwork,
                              float pivmin,
                              float spdiam,
                              int twist,
                              intW info)

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