Unix/Linux Go Back    


CentOS 7.0 - man page for slasq1 (centos section 3)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


slasq1.f(3)				      LAPACK				      slasq1.f(3)

NAME
       slasq1.f -

SYNOPSIS
   Functions/Subroutines
       subroutine slasq1 (N, D, E, WORK, INFO)
	   SLASQ1 computes the singular values of a real square bidiagonal matrix. Used by
	   sbdsqr.

Function/Subroutine Documentation
   subroutine slasq1 (integerN, real, dimension( * )D, real, dimension( * )E, real, dimension( *
       )WORK, integerINFO)
       SLASQ1 computes the singular values of a real square bidiagonal matrix. Used by sbdsqr.

       Purpose:

	    SLASQ1 computes the singular values of a real N-by-N bidiagonal
	    matrix with diagonal D and off-diagonal 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., Vol-67, No. 2, pp. 191-230,
	    1994,

	    and the present implementation is described in "An implementation of
	    the dqds Algorithm (Positive Case)", LAPACK Working Note.

       Parameters:
	   N

		     N is INTEGER
		   The number of rows and columns in the matrix. N >= 0.

	   D

		     D is REAL 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

		     E is REAL array, dimension (N)
		   On entry, elements E(1:N-1) contain the off-diagonal elements
		   of the bidiagonal matrix whose SVD is desired.
		   On exit, E is overwritten.

	   WORK

		     WORK is REAL array, dimension (4*N)

	   INFO

		     INFO is INTEGER
		   = 0: successful exit
		   < 0: if INFO = -i, the i-th 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 100*N
			     iterations (in inner while loop)  On exit D and E
			     represent a matrix with the same singular values
			     which the calling subroutine could use to finish the
			     computation, or even feed back into SLASQ1
			= 3, termination criterion of outer while loop not met
			     (program created more than N unreduced blocks)

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Definition at line 109 of file slasq1.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2				 Tue Sep 25 2012			      slasq1.f(3)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 01:49 PM.