org.netlib.lapack
Class DLARRK

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

public class DLARRK
extends java.lang.Object

DLARRK is a simplified interface to the JLAPACK routine dlarrk.
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 * ======= * * DLARRK computes one eigenvalue of a symmetric tridiagonal * matrix T to suitable accuracy. This is an auxiliary code to be * called from DSTEMR. * * To avoid overflow, the matrix must be scaled so that its * largest element is no greater than overflow**(1/2) * * underflow**(1/4) in absolute value, and for greatest * accuracy, it should not be much smaller than that. * * See W. Kahan "Accurate Eigenvalues of a Symmetric Tridiagonal * Matrix", Report CS41, Computer Science Dept., Stanford * University, July 21, 1966. * * Arguments * ========= * * N (input) INTEGER * The order of the tridiagonal matrix T. N >= 0. * * IW (input) INTEGER * The index of the eigenvalues to be returned. * * GL (input) DOUBLE PRECISION * GU (input) DOUBLE PRECISION * An upper and a lower bound on the eigenvalue. * * D (input) DOUBLE PRECISION array, dimension (N) * The n diagonal elements of the tridiagonal matrix T. * * E2 (input) DOUBLE PRECISION array, dimension (N-1) * The (n-1) squared off-diagonal elements of the tridiagonal ma * * PIVMIN (input) DOUBLE PRECISION * The minimum pivot allowed in the Sturm sequence for T. * * RELTOL (input) DOUBLE PRECISION * The minimum relative width of an interval. When an interval * is narrower than RELTOL times the larger (in * magnitude) endpoint, then it is considered to be * sufficiently small, i.e., converged. Note: this should * always be at least radix*machine epsilon. * * W (output) DOUBLE PRECISION * * WERR (output) DOUBLE PRECISION * The error bound on the corresponding eigenvalue approximation * in W. * * INFO (output) INTEGER * = 0: Eigenvalue converged * = -1: Eigenvalue did NOT converge * * Internal Parameters * =================== * * FUDGE DOUBLE PRECISION, default = 2 * A "fudge factor" to widen the Gershgorin intervals. * * ===================================================================== * * .. Parameters ..


Constructor Summary
DLARRK()
           
 
Method Summary
static void DLARRK(int n, int iw, double gl, double gu, double[] d, double[] e2, double pivmin, double reltol, doubleW w, doubleW werr, intW info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DLARRK

public DLARRK()
Method Detail

DLARRK

public static void DLARRK(int n,
                          int iw,
                          double gl,
                          double gu,
                          double[] d,
                          double[] e2,
                          double pivmin,
                          double reltol,
                          doubleW w,
                          doubleW werr,
                          intW info)