Class DLASQ1

  extended by org.netlib.lapack.DLASQ1

public class DLASQ1
extends java.lang.Object

DLASQ1 is a simplified interface to the JLAPACK routine dlasq1.
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 with any questions.

* .. * * Purpose * ======= * * DLASQ1 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) DOUBLE PRECISION 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) DOUBLE PRECISION 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) DOUBLE PRECISION 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
Method Summary
static void DLASQ1(int n, double[] d, double[] e, double[] work, intW info)
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail


public DLASQ1()
Method Detail


public static void DLASQ1(int n,
                          double[] d,
                          double[] e,
                          double[] work,
                          intW info)