Unix/Linux Go Back    

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

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

sdisna.f(3)				      LAPACK				      sdisna.f(3)

       sdisna.f -

       subroutine sdisna (JOB, M, N, D, SEP, INFO)

Function/Subroutine Documentation
   subroutine sdisna (characterJOB, integerM, integerN, real, dimension( * )D, real, dimension( *
       )SEP, integerINFO)


	    SDISNA computes the reciprocal condition numbers for the eigenvectors
	    of a real symmetric or complex Hermitian matrix or for the left or
	    right singular vectors of a general m-by-n matrix. The reciprocal
	    condition number is the 'gap' between the corresponding eigenvalue or
	    singular value and the nearest other one.

	    The bound on the error, measured by angle in radians, in the I-th
	    computed vector is given by

		   SLAMCH( 'E' ) * ( ANORM / SEP( I ) )

	    where ANORM = 2-norm(A) = max( abs( D(j) ) ).  SEP(I) is not allowed
	    to be smaller than SLAMCH( 'E' )*ANORM in order to limit the size of
	    the error bound.

	    SDISNA may also be used to compute error bounds for eigenvectors of
	    the generalized symmetric definite eigenproblem.


		     JOB is CHARACTER*1
		     Specifies for which problem the reciprocal condition numbers
		     should be computed:
		     = 'E':  the eigenvectors of a symmetric/Hermitian matrix;
		     = 'L':  the left singular vectors of a general matrix;
		     = 'R':  the right singular vectors of a general matrix.


		     M is INTEGER
		     The number of rows of the matrix. M >= 0.


		     N is INTEGER
		     If JOB = 'L' or 'R', the number of columns of the matrix,
		     in which case N >= 0. Ignored if JOB = 'E'.


		     D is REAL array, dimension (M) if JOB = 'E'
					 dimension (min(M,N)) if JOB = 'L' or 'R'
		     The eigenvalues (if JOB = 'E') or singular values (if JOB =
		     'L' or 'R') of the matrix, in either increasing or decreasing
		     order. If singular values, they must be non-negative.


		     SEP is REAL array, dimension (M) if JOB = 'E'
					  dimension (min(M,N)) if JOB = 'L' or 'R'
		     The reciprocal condition numbers of the vectors.


		     INFO is INTEGER
		     = 0:  successful exit.
		     < 0:  if INFO = -i, the i-th argument had an illegal value.

	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

	   November 2011

       Definition at line 118 of file sdisna.f.

       Generated automatically by Doxygen for LAPACK from the source code.

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

All times are GMT -4. The time now is 08:03 PM.