org.netlib.lapack
Class SLASQ1

java.lang.Object
  org.netlib.lapack.SLASQ1

public class SLASQ1
extends java.lang.Object

SLASQ1 is a simplified interface to the JLAPACK routine slasq1.
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
 *  =======
 *
 *  SLASQ1 computes the singular values of a real N-by-N bidiagonal
 *  matrix with diagonal D and off-diagonal E. The singular values
 *  are computed to high relative accuracy, in the absence of
 *  denormalization, underflow and overflow. The algorithm was first
 *  presented in
 *
 *  "Accurate singular values and differential qd algorithms" by K. V.
 *  Fernando and B. N. Parlett, Numer. Math., Vol-67, No. 2, pp. 191-230,
 *  1994,
 *
 *  and the present implementation is described in "An implementation of

 *  the dqds Algorithm (Positive Case)", LAPACK Working Note.
 *
 *  Arguments
 *  =========
 *
 *  N     (input) INTEGER
 *        The number of rows and columns in the matrix. N >= 0.
 *
 *  D     (input/output) REAL array, dimension (N)
 *        On entry, D contains the diagonal elements of the
 *        bidiagonal matrix whose SVD is desired. On normal exit,
 *        D contains the singular values in decreasing order.
 *
 *  E     (input/output) REAL array, dimension (N)
 *        On entry, elements E(1:N-1) contain the off-diagonal elements
 *        of the bidiagonal matrix whose SVD is desired.
 *        On exit, E is overwritten.
 *
 *  WORK  (workspace) REAL array, dimension (4*N)
 *
 *  INFO  (output) INTEGER
 *        = 0: successful exit
 *        < 0: if INFO = -i, the i-th argument had an illegal value
 *        > 0: the algorithm failed
 *             = 1, a split was marked by a positive value in E
 *             = 2, current block of Z not diagonalized after 30*N
 *                  iterations (in inner while loop)
 *             = 3, termination criterion of outer while loop not met 
 *                  (program created more than N unreduced blocks)
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

SLASQ1()

Method Summary

static void

SLASQ1(int n, float[] d, float[] e, float[] work, intW info)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SLASQ1

public SLASQ1()

Method Detail

SLASQ1

public static void SLASQ1(int n,
                          float[] d,
                          float[] e,
                          float[] work,
                          intW info)