org.netlib.lapack
Class Slasda

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

public class Slasda
extends java.lang.Object

Following is the description from the original
Fortran source.  For each array argument, the Java
version will include an integer offset parameter, so
the arguments may not match the description exactly.
Contact seymour@cs.utk.edu with any questions.

* .. * * Purpose * ======= * * Using a divide and conquer approach, SLASDA computes the singular * value decomposition (SVD) of a real upper bidiagonal N-by-M matrix * B with diagonal D and offdiagonal E, where M = N + SQRE. The * algorithm computes the singular values in the SVD B = U * S * VT. * The orthogonal matrices U and VT are optionally computed in * compact form. * * A related subroutine, SLASD0, computes the singular values and * the singular vectors in explicit form. * * Arguments * ========= * * ICOMPQ (input) INTEGER * Specifies whether singular vectors are to be computed * in compact form, as follows * = 0: Compute singular values only. * = 1: Compute singular vectors of upper bidiagonal * matrix in compact form. * * SMLSIZ (input) INTEGER * The maximum size of the subproblems at the bottom of the * computation tree. * * N (input) INTEGER * The row dimension of the upper bidiagonal matrix. This is * also the dimension of the main diagonal array D. * * SQRE (input) INTEGER * Specifies the column dimension of the bidiagonal matrix. * = 0: The bidiagonal matrix has column dimension M = N; * = 1: The bidiagonal matrix has column dimension M = N + 1. * * D (input/output) REAL array, dimension ( N ) * On entry D contains the main diagonal of the bidiagonal * matrix. On exit D, if INFO = 0, contains its singular values. * * E (input) REAL array, dimension ( M-1 ) * Contains the subdiagonal entries of the bidiagonal matrix. * On exit, E has been destroyed. * * U (output) REAL array, * dimension ( LDU, SMLSIZ ) if ICOMPQ = 1, and not referenced * if ICOMPQ = 0. If ICOMPQ = 1, on exit, 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 (output) REAL array, * dimension ( LDU, SMLSIZ+1 ) if ICOMPQ = 1, and not referenced * if ICOMPQ = 0. If ICOMPQ = 1, on exit, VT' contains the right * singular vector matrices of all subproblems at the bottom * level. * * K (output) INTEGER array, * dimension ( N ) if ICOMPQ = 1 and dimension 1 if ICOMPQ = 0. * If ICOMPQ = 1, on exit, K(I) is the dimension of the I-th * secular equation on the computation tree. * * DIFL (output) REAL array, dimension ( LDU, NLVL ), * where NLVL = floor(log_2 (N/SMLSIZ))). * * DIFR (output) REAL array, * dimension ( LDU, 2 * NLVL ) if ICOMPQ = 1 and * dimension ( N ) if ICOMPQ = 0. * If ICOMPQ = 1, on exit, DIFL(1:N, I) and DIFR(1:N, 2 * I - 1) * record distances between singular values on the I-th * level and singular values on the (I -1)-th level, and * DIFR(1:N, 2 * I ) contains the normalizing factors for * the right singular vector matrix. See SLASD8 for details. * * Z (output) REAL array, * dimension ( LDU, NLVL ) if ICOMPQ = 1 and * dimension ( N ) if ICOMPQ = 0. * The first K elements of Z(1, I) contain the components of * the deflation-adjusted updating row vector for subproblems * on the I-th level. * * POLES (output) REAL array, * dimension ( LDU, 2 * NLVL ) if ICOMPQ = 1, and not referenced * if ICOMPQ = 0. If ICOMPQ = 1, on exit, POLES(1, 2*I - 1) and * POLES(1, 2*I) contain the new and old singular values * involved in the secular equations on the I-th level. * * GIVPTR (output) INTEGER array, * dimension ( N ) if ICOMPQ = 1, and not referenced if * ICOMPQ = 0. If ICOMPQ = 1, on exit, GIVPTR( I ) records * the number of Givens rotations performed on the I-th * problem on the computation tree. * * GIVCOL (output) INTEGER array, * dimension ( LDGCOL, 2 * NLVL ) if ICOMPQ = 1, and not * referenced if ICOMPQ = 0. If ICOMPQ = 1, on exit, for each I, * GIVCOL(1, 2 *I - 1) and GIVCOL(1, 2 *I) record 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 (output) INTEGER array, * dimension ( LDGCOL, NLVL ) if ICOMPQ = 1, and not referenced * if ICOMPQ = 0. If ICOMPQ = 1, on exit, PERM(1, I) records * permutations done on the I-th level of the computation tree. * * GIVNUM (output) REAL array, * dimension ( LDU, 2 * NLVL ) if ICOMPQ = 1, and not * referenced if ICOMPQ = 0. If ICOMPQ = 1, on exit, for each I, * GIVNUM(1, 2 *I - 1) and GIVNUM(1, 2 *I) record the C- and S- * values of Givens rotations performed on the I-th level on * the computation tree. * * C (output) REAL array, * dimension ( N ) if ICOMPQ = 1, and dimension 1 if ICOMPQ = 0. * If ICOMPQ = 1 and the I-th subproblem is not square, on exit, * C( I ) contains the C-value of a Givens rotation related to * the right null space of the I-th subproblem. * * S (output) REAL array, dimension ( N ) if * ICOMPQ = 1, and dimension 1 if ICOMPQ = 0. If ICOMPQ = 1 * and the I-th subproblem is not square, on exit, S( I ) * contains the S-value of a Givens rotation related to * the right null space of the I-th subproblem. * * WORK (workspace) REAL array, dimension * (6 * N + (SMLSIZ + 1)*(SMLSIZ + 1)). * * IWORK (workspace) INTEGER array. * Dimension must be at least (7 * N). * * INFO (output) INTEGER * = 0: successful exit. * < 0: if INFO = -i, the i-th argument had an illegal value. * > 0: if INFO = 1, an singular value did not converge * * Further Details * =============== * * Based on contributions by * Ming Gu and Huan Ren, Computer Science Division, University of * California at Berkeley, USA * * ===================================================================== * * .. Parameters ..


Constructor Summary
Slasda()
           
 
Method Summary
static void slasda(int icompq, int smlsiz, int n, int sqre, float[] d, int _d_offset, float[] e, int _e_offset, float[] u, int _u_offset, int ldu, float[] vt, int _vt_offset, int[] k, int _k_offset, float[] difl, int _difl_offset, float[] difr, int _difr_offset, float[] z, int _z_offset, float[] poles, int _poles_offset, int[] givptr, int _givptr_offset, int[] givcol, int _givcol_offset, int ldgcol, int[] perm, int _perm_offset, float[] givnum, int _givnum_offset, float[] c, int _c_offset, float[] s, int _s_offset, float[] work, int _work_offset, int[] iwork, int _iwork_offset, intW info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Slasda

public Slasda()
Method Detail

slasda

public static void slasda(int icompq,
                          int smlsiz,
                          int n,
                          int sqre,
                          float[] d,
                          int _d_offset,
                          float[] e,
                          int _e_offset,
                          float[] u,
                          int _u_offset,
                          int ldu,
                          float[] vt,
                          int _vt_offset,
                          int[] k,
                          int _k_offset,
                          float[] difl,
                          int _difl_offset,
                          float[] difr,
                          int _difr_offset,
                          float[] z,
                          int _z_offset,
                          float[] poles,
                          int _poles_offset,
                          int[] givptr,
                          int _givptr_offset,
                          int[] givcol,
                          int _givcol_offset,
                          int ldgcol,
                          int[] perm,
                          int _perm_offset,
                          float[] givnum,
                          int _givnum_offset,
                          float[] c,
                          int _c_offset,
                          float[] s,
                          int _s_offset,
                          float[] work,
                          int _work_offset,
                          int[] iwork,
                          int _iwork_offset,
                          intW info)