org.netlib.lapack
Class DLALSA

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

public class DLALSA
extends java.lang.Object

DLALSA is a simplified interface to the JLAPACK routine dlalsa.
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 * ======= * * DLALSA is an itermediate step in solving the least squares problem * by computing the SVD of the coefficient matrix in compact form (The * singular vectors are computed as products of simple orthorgonal * matrices.). * * If ICOMPQ = 0, DLALSA applies the inverse of the left singular vector * matrix of an upper bidiagonal matrix to the right hand side; and if * ICOMPQ = 1, DLALSA applies the right singular vector matrix to the * right hand side. The singular vector matrices were generated in * compact form by DLALSA. * * Arguments * ========= * * * ICOMPQ (input) INTEGER * Specifies whether the left or the right singular vector * matrix is involved. * = 0: Left singular vector matrix * = 1: Right singular vector matrix * * SMLSIZ (input) INTEGER * The maximum size of the subproblems at the bottom of the * computation tree. * * N (input) INTEGER * The row and column dimensions of the upper bidiagonal matrix. * * NRHS (input) INTEGER * The number of columns of B and BX. NRHS must be at least 1. * * B (input) DOUBLE PRECISION array, dimension ( LDB, NRHS ) * On input, B contains the right hand sides of the least * squares problem in rows 1 through M. On output, B contains * the solution X in rows 1 through N. * * LDB (input) INTEGER * The leading dimension of B in the calling subprogram. * LDB must be at least max(1,MAX( M, N ) ). * * BX (output) DOUBLE PRECISION array, dimension ( LDBX, NRHS ) * On exit, the result of applying the left or right singular * vector matrix to B. * * LDBX (input) INTEGER * The leading dimension of BX. * * U (input) DOUBLE PRECISION array, dimension ( LDU, SMLSIZ ). * On entry, U contains the left singular vector matrices of all * subproblems at the bottom level. * * LDU (input) INTEGER, LDU = > N. * The leading dimension of arrays U, VT, DIFL, DIFR, * POLES, GIVNUM, and Z. * * VT (input) DOUBLE PRECISION array, dimension ( LDU, SMLSIZ+1 ). * On entry, VT' contains the right singular vector matrices of * all subproblems at the bottom level. * * K (input) INTEGER array, dimension ( N ). * * DIFL (input) DOUBLE PRECISION array, dimension ( LDU, NLVL ). * where NLVL = INT(log_2 (N/(SMLSIZ+1))) + 1. * * DIFR (input) DOUBLE PRECISION array, dimension ( LDU, 2 * NLVL ). * On entry, DIFL(*, I) and DIFR(*, 2 * I -1) record * distances between singular values on the I-th level and * singular values on the (I -1)-th level, and DIFR(*, 2 * I) * record the normalizing factors of the right singular vectors * matrices of subproblems on I-th level. * * Z (input) DOUBLE PRECISION array, dimension ( LDU, NLVL ). * On entry, Z(1, I) contains the components of the deflation- * adjusted updating row vector for subproblems on the I-th * level. * * POLES (input) DOUBLE PRECISION array, dimension ( LDU, 2 * NLVL ). * On entry, POLES(*, 2 * I -1: 2 * I) contains the new and old * singular values involved in the secular equations on the I-th * level. * * GIVPTR (input) INTEGER array, dimension ( N ). * On entry, GIVPTR( I ) records the number of Givens * rotations performed on the I-th problem on the computation * tree. * * GIVCOL (input) INTEGER array, dimension ( LDGCOL, 2 * NLVL ). * On entry, for each I, GIVCOL(*, 2 * I - 1: 2 * I) records the * locations of Givens rotations performed on the I-th level on * the computation tree. * * LDGCOL (input) INTEGER, LDGCOL = > N. * The leading dimension of arrays GIVCOL and PERM. * * PERM (input) INTEGER array, dimension ( LDGCOL, NLVL ). * On entry, PERM(*, I) records permutations done on the I-th * level of the computation tree. * * GIVNUM (input) DOUBLE PRECISION array, dimension ( LDU, 2 * NLVL ). * On entry, GIVNUM(*, 2 *I -1 : 2 * I) records the C- and S- * values of Givens rotations performed on the I-th level on the * computation tree. * * C (input) DOUBLE PRECISION array, dimension ( N ). * On entry, if the I-th subproblem is not square, * C( I ) contains the C-value of a Givens rotation related to * the right null space of the I-th subproblem. * * S (input) DOUBLE PRECISION array, dimension ( N ). * On entry, if the I-th subproblem is not square, * S( I ) contains the S-value of a Givens rotation related to * the right null space of the I-th subproblem. * * WORK (workspace) DOUBLE PRECISION array. * The dimension must be at least N. * * IWORK (workspace) INTEGER array. * The dimension must be at least 3 * N * * INFO (output) INTEGER * = 0: successful exit. * < 0: if INFO = -i, the i-th argument had an illegal value. * * Further Details * =============== * * Based on contributions by * Ming Gu and Ren-Cang Li, Computer Science Division, University of * California at Berkeley, USA * Osni Marques, LBNL/NERSC, USA * * ===================================================================== * * .. Parameters ..


Constructor Summary
DLALSA()
           
 
Method Summary
static void DLALSA(int icompq, int smlsiz, int n, int nrhs, double[][] b, double[][] bx, double[][] u, double[][] vt, int[] k, double[][] difl, double[][] difr, double[][] z, double[][] poles, int[] givptr, int[][] givcol, int[][] perm, double[][] givnum, double[] c, double[] s, double[] work, int[] iwork, intW info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DLALSA

public DLALSA()
Method Detail

DLALSA

public static void DLALSA(int icompq,
                          int smlsiz,
                          int n,
                          int nrhs,
                          double[][] b,
                          double[][] bx,
                          double[][] u,
                          double[][] vt,
                          int[] k,
                          double[][] difl,
                          double[][] difr,
                          double[][] z,
                          double[][] poles,
                          int[] givptr,
                          int[][] givcol,
                          int[][] perm,
                          double[][] givnum,
                          double[] c,
                          double[] s,
                          double[] work,
                          int[] iwork,
                          intW info)