org.netlib.lapack
Class DLASQ1
java.lang.Object
org.netlib.lapack.DLASQ1
public class DLASQ1
 extends java.lang.Object
DLASQ1 is a simplified interface to the JLAPACK routine dlasq1.
This interface converts Javastyle 2D rowmajor arrays into
the 1D columnmajor 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
* =======
*
* DLASQ1 computes the singular values of a real NbyN bidiagonal
* matrix with diagonal D and offdiagonal 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., Vol67, No. 2, pp. 191230,
* 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:N1) contain the offdiagonal 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 ith 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 ..
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 
DLASQ1
public DLASQ1()
DLASQ1
public static void DLASQ1(int n,
double[] d,
double[] e,
double[] work,
intW info)