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CentOS 7.0 - man page for dgsvj0 (centos section 3)

dgsvj0.f(3)						LAPACK						  dgsvj0.f(3)

NAME
dgsvj0.f -
SYNOPSIS
Functions/Subroutines subroutine dgsvj0 (JOBV, M, N, A, LDA, D, SVA, MV, V, LDV, EPS, SFMIN, TOL, NSWEEP, WORK, LWORK, INFO) DGSVJ0 pre-processor for the routine sgesvj. Function/Subroutine Documentation subroutine dgsvj0 (character*1JOBV, integerM, integerN, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( n )D, double precision, dimension( n )SVA, integerMV, double precision, dimension( ldv, * )V, integerLDV, double precisionEPS, double precisionSFMIN, double precisionTOL, integerNSWEEP, double precision, dimension( lwork )WORK, integerLWORK, integerINFO) DGSVJ0 pre-processor for the routine sgesvj. Purpose: DGSVJ0 is called from DGESVJ as a pre-processor and that is its main purpose. It applies Jacobi rotations in the same way as DGESVJ does, but it does not check convergence (stopping criterion). Few tuning parameters (marked by [TP]) are available for the implementer. Parameters: JOBV JOBV is CHARACTER*1 Specifies whether the output from this procedure is used to compute the matrix V: = 'V': the product of the Jacobi rotations is accumulated by postmulyiplying the N-by-N array V. (See the description of V.) = 'A': the product of the Jacobi rotations is accumulated by postmulyiplying the MV-by-N array V. (See the descriptions of MV and V.) = 'N': the Jacobi rotations are not accumulated. M M is INTEGER The number of rows of the input matrix A. M >= 0. N N is INTEGER The number of columns of the input matrix A. M >= N >= 0. A A is DOUBLE PRECISION array, dimension (LDA,N) On entry, M-by-N matrix A, such that A*diag(D) represents the input matrix. On exit, A_onexit * D_onexit represents the input matrix A*diag(D) post-multiplied by a sequence of Jacobi rotations, where the rotation threshold and the total number of sweeps are given in TOL and NSWEEP, respectively. (See the descriptions of D, TOL and NSWEEP.) LDA LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M). D D is DOUBLE PRECISION array, dimension (N) The array D accumulates the scaling factors from the fast scaled Jacobi rotations. On entry, A*diag(D) represents the input matrix. On exit, A_onexit*diag(D_onexit) represents the input matrix post-multiplied by a sequence of Jacobi rotations, where the rotation threshold and the total number of sweeps are given in TOL and NSWEEP, respectively. (See the descriptions of A, TOL and NSWEEP.) SVA SVA is DOUBLE PRECISION array, dimension (N) On entry, SVA contains the Euclidean norms of the columns of the matrix A*diag(D). On exit, SVA contains the Euclidean norms of the columns of the matrix onexit*diag(D_onexit). MV MV is INTEGER If JOBV .EQ. 'A', then MV rows of V are post-multipled by a sequence of Jacobi rotations. If JOBV = 'N', then MV is not referenced. V V is DOUBLE PRECISION array, dimension (LDV,N) If JOBV .EQ. 'V' then N rows of V are post-multipled by a sequence of Jacobi rotations. If JOBV .EQ. 'A' then MV rows of V are post-multipled by a sequence of Jacobi rotations. If JOBV = 'N', then V is not referenced. LDV LDV is INTEGER The leading dimension of the array V, LDV >= 1. If JOBV = 'V', LDV .GE. N. If JOBV = 'A', LDV .GE. MV. EPS EPS is DOUBLE PRECISION EPS = DLAMCH('Epsilon') SFMIN SFMIN is DOUBLE PRECISION SFMIN = DLAMCH('Safe Minimum') TOL TOL is DOUBLE PRECISION TOL is the threshold for Jacobi rotations. For a pair A(:,p), A(:,q) of pivot columns, the Jacobi rotation is applied only if DABS(COS(angle(A(:,p),A(:,q)))) .GT. TOL. NSWEEP NSWEEP is INTEGER NSWEEP is the number of sweeps of Jacobi rotations to be performed. WORK WORK is DOUBLE PRECISION array, dimension (LWORK) LWORK LWORK is INTEGER LWORK is the dimension of WORK. LWORK .GE. M. INFO INFO is INTEGER = 0 : successful exit. < 0 : if INFO = -i, then the i-th argument had an illegal value Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Further Details: DGSVJ0 is used just to enable DGESVJ to call a simplified version of itself to work on a submatrix of the original matrix. Contributors: Zlatko Drmac (Zagreb, Croatia) and Kresimir Veselic (Hagen, Germany) Bugs, Examples and Comments: Please report all bugs and send interesting test examples and comments to drmac@math.hr. Thank you. Definition at line 218 of file dgsvj0.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.2 Tue Sep 25 2012 dgsvj0.f(3)


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