org.netlib.lapack
Class Slasdq

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

public class Slasdq
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 * ======= * * SLASDQ computes the singular value decomposition (SVD) of a real * (upper or lower) bidiagonal matrix with diagonal D and offdiagonal * E, accumulating the transformations if desired. Letting B denote * the input bidiagonal matrix, the algorithm computes orthogonal * matrices Q and P such that B = Q * S * P' (P' denotes the transpose * of P). The singular values S are overwritten on D. * * The input matrix U is changed to U * Q if desired. * The input matrix VT is changed to P' * VT if desired. * The input matrix C is changed to Q' * C if desired. * * See "Computing Small Singular Values of Bidiagonal Matrices With * Guaranteed High Relative Accuracy," by J. Demmel and W. Kahan, * LAPACK Working Note #3, for a detailed description of the algorithm. * * Arguments * ========= * * UPLO (input) CHARACTER*1 * On entry, UPLO specifies whether the input bidiagonal matrix * is upper or lower bidiagonal, and wether it is square are * not. * UPLO = 'U' or 'u' B is upper bidiagonal. * UPLO = 'L' or 'l' B is lower bidiagonal. * * SQRE (input) INTEGER * = 0: then the input matrix is N-by-N. * = 1: then the input matrix is N-by-(N+1) if UPLU = 'U' and * (N+1)-by-N if UPLU = 'L'. * * The bidiagonal matrix has * N = NL + NR + 1 rows and * M = N + SQRE >= N columns. * * N (input) INTEGER * On entry, N specifies the number of rows and columns * in the matrix. N must be at least 0. * * NCVT (input) INTEGER * On entry, NCVT specifies the number of columns of * the matrix VT. NCVT must be at least 0. * * NRU (input) INTEGER * On entry, NRU specifies the number of rows of * the matrix U. NRU must be at least 0. * * NCC (input) INTEGER * On entry, NCC specifies the number of columns of * the matrix C. NCC must be at least 0. * * D (input/output) REAL array, dimension (N) * On entry, D contains the diagonal entries of the * bidiagonal matrix whose SVD is desired. On normal exit, * D contains the singular values in ascending order. * * E (input/output) REAL array. * dimension is (N-1) if SQRE = 0 and N if SQRE = 1. * On entry, the entries of E contain the offdiagonal entries * of the bidiagonal matrix whose SVD is desired. On normal * exit, E will contain 0. If the algorithm does not converge, * D and E will contain the diagonal and superdiagonal entries * of a bidiagonal matrix orthogonally equivalent to the one * given as input. * * VT (input/output) REAL array, dimension (LDVT, NCVT) * On entry, contains a matrix which on exit has been * premultiplied by P', dimension N-by-NCVT if SQRE = 0 * and (N+1)-by-NCVT if SQRE = 1 (not referenced if NCVT=0). * * LDVT (input) INTEGER * On entry, LDVT specifies the leading dimension of VT as * declared in the calling (sub) program. LDVT must be at * least 1. If NCVT is nonzero LDVT must also be at least N. * * U (input/output) REAL array, dimension (LDU, N) * On entry, contains a matrix which on exit has been * postmultiplied by Q, dimension NRU-by-N if SQRE = 0 * and NRU-by-(N+1) if SQRE = 1 (not referenced if NRU=0). * * LDU (input) INTEGER * On entry, LDU specifies the leading dimension of U as * declared in the calling (sub) program. LDU must be at * least max( 1, NRU ) . * * C (input/output) REAL array, dimension (LDC, NCC) * On entry, contains an N-by-NCC matrix which on exit * has been premultiplied by Q' dimension N-by-NCC if SQRE = 0 * and (N+1)-by-NCC if SQRE = 1 (not referenced if NCC=0). * * LDC (input) INTEGER * On entry, LDC specifies the leading dimension of C as * declared in the calling (sub) program. LDC must be at * least 1. If NCC is nonzero, LDC must also be at least N. * * WORK (workspace) REAL array, dimension (4*N) * Workspace. Only referenced if one of NCVT, NRU, or NCC is * nonzero, and if N is at least 2. * * INFO (output) INTEGER * On exit, a value of 0 indicates a successful exit. * If INFO < 0, argument number -INFO is illegal. * If INFO > 0, the algorithm did not converge, and INFO * specifies how many superdiagonals 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
Slasdq()
           
 
Method Summary
static void slasdq(java.lang.String uplo, int sqre, int n, int ncvt, int nru, int ncc, float[] d, int _d_offset, float[] e, int _e_offset, float[] vt, int _vt_offset, int ldvt, float[] u, int _u_offset, int ldu, float[] c, int _c_offset, int Ldc, float[] work, int _work_offset, intW info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Slasdq

public Slasdq()
Method Detail

slasdq

public static void slasdq(java.lang.String uplo,
                          int sqre,
                          int n,
                          int ncvt,
                          int nru,
                          int ncc,
                          float[] d,
                          int _d_offset,
                          float[] e,
                          int _e_offset,
                          float[] vt,
                          int _vt_offset,
                          int ldvt,
                          float[] u,
                          int _u_offset,
                          int ldu,
                          float[] c,
                          int _c_offset,
                          int Ldc,
                          float[] work,
                          int _work_offset,
                          intW info)