zrotg(3) [debian man page]

ZROTG(3)							   BLAS routine 							  ZROTG(3)

NAME

       ZROTG - construct givens plane rotation

SYNOPSIS

       subroutine zrotg(ca,cb,c,s)

	   double		   complex ca,cb,s

	   double		   precision c

	   double		   precision norm,scale

	   double		   complex alpha

	   if			   (cdabs(ca) .ne. 0.0d0) go to 10

	   c			   = 0.0d0

	   s			   = (1.0d0,0.0d0)

	   ca			   = cb

	   go			   to 20

	   10			   continue

	   scale		   = cdabs(ca) + cdabs(cb)

	   norm 		   = scale*dsqrt((cdabs(ca/dcmplx(scale,0.0d0)))**2 +

	   *			   (cdabs(cb/dcmplx(scale,0.0d0)))**2)

	   alpha		   = ca /cdabs(ca)

	   c			   = cdabs(ca) / norm

	   s			   = alpha * dconjg(cb) / norm

	   ca			   = alpha * norm

	   20			   continue

	   return

	   end

PURPOSE

BLAS routine							  16 October 1992							  ZROTG(3)

zgecon.f(3)							      LAPACK							       zgecon.f(3)

NAME

       zgecon.f -

SYNOPSIS

   Functions/Subroutines
       subroutine zgecon (NORM, N, A, LDA, ANORM, RCOND, WORK, RWORK, INFO)
	   ZGECON

Function/Subroutine Documentation
   subroutine zgecon (characterNORM, integerN, complex*16, dimension( lda, * )A, integerLDA, double precisionANORM, double precisionRCOND,
       complex*16, dimension( * )WORK, double precision, dimension( * )RWORK, integerINFO)
       ZGECON

       Purpose:

	    ZGECON estimates the reciprocal of the condition number of a general
	    complex matrix A, in either the 1-norm or the infinity-norm, using
	    the LU factorization computed by ZGETRF.

	    An estimate is obtained for norm(inv(A)), and the reciprocal of the
	    condition number is computed as
	       RCOND = 1 / ( norm(A) * norm(inv(A)) ).

       Parameters:
	   NORM

		     NORM is CHARACTER*1
		     Specifies whether the 1-norm condition number or the
		     infinity-norm condition number is required:
		     = '1' or 'O':  1-norm;
		     = 'I':	    Infinity-norm.

	   N

		     N is INTEGER
		     The order of the matrix A.  N >= 0.

	   A

		     A is COMPLEX*16 array, dimension (LDA,N)
		     The factors L and U from the factorization A = P*L*U
		     as computed by ZGETRF.

	   LDA

		     LDA is INTEGER
		     The leading dimension of the array A.  LDA >= max(1,N).

	   ANORM

		     ANORM is DOUBLE PRECISION
		     If NORM = '1' or 'O', the 1-norm of the original matrix A.
		     If NORM = 'I', the infinity-norm of the original matrix A.

	   RCOND

		     RCOND is DOUBLE PRECISION
		     The reciprocal of the condition number of the matrix A,
		     computed as RCOND = 1/(norm(A) * norm(inv(A))).

	   WORK

		     WORK is COMPLEX*16 array, dimension (2*N)

	   RWORK

		     RWORK is DOUBLE PRECISION array, dimension (2*N)

	   INFO

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

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 124 of file zgecon.f.

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

Version 3.4.2							  Tue Sep 25 2012						       zgecon.f(3)