drotmg(3) [centos man page]

drotmg.f(3)							      LAPACK							       drotmg.f(3)

NAME

       drotmg.f -

SYNOPSIS

   Functions/Subroutines
       subroutine drotmg (DD1, DD2, DX1, DY1, DPARAM)
	   DROTMG

Function/Subroutine Documentation
   subroutine drotmg (double precisionDD1, double precisionDD2, double precisionDX1, double precisionDY1, double precision, dimension(5)DPARAM)
       DROTMG Purpose:

	       CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS
	       THE SECOND COMPONENT OF THE 2-VECTOR  (DSQRT(DD1)*DX1,DSQRT(DD2)*>    DY2)**T.
	       WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS..

	       DFLAG=-1.D0     DFLAG=0.D0	 DFLAG=1.D0	DFLAG=-2.D0

		 (DH11	DH12)	 (1.D0	DH12)	 (DH11	1.D0)	 (1.D0	0.D0)
	       H=(	    )	 (	    )	 (	    )	 (	    )
		 (DH21	DH22),	 (DH21	1.D0),	 (-1.D0 DH22),	 (0.D0	1.D0).
	       LOCATIONS 2-4 OF DPARAM CONTAIN DH11, DH21, DH12, AND DH22
	       RESPECTIVELY. (VALUES OF 1.D0, -1.D0, OR 0.D0 IMPLIED BY THE
	       VALUE OF DPARAM(1) ARE NOT STORED IN DPARAM.)

	       THE VALUES OF GAMSQ AND RGAMSQ SET IN THE DATA STATEMENT MAY BE
	       INEXACT.  THIS IS OK AS THEY ARE ONLY USED FOR TESTING THE SIZE
	       OF DD1 AND DD2.	ALL ACTUAL SCALING OF DATA IS DONE USING GAM.

       Parameters:
	   DD1

		     DD1 is DOUBLE PRECISION

	   DD2

		     DD2 is DOUBLE PRECISION

	   DX1

		     DX1 is DOUBLE PRECISION

	   DY1

		     DY1 is DOUBLE PRECISION

	   DPARAM

		     DPARAM is DOUBLE PRECISION array, dimension 5
		DPARAM(1)=DFLAG
		DPARAM(2)=DH11
		DPARAM(3)=DH21
		DPARAM(4)=DH12
		DPARAM(5)=DH22

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 91 of file drotmg.f.

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

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

dlanv2.f(3)							      LAPACK							       dlanv2.f(3)

NAME

       dlanv2.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dlanv2 (A, B, C, D, RT1R, RT1I, RT2R, RT2I, CS, SN)
	   DLANV2

Function/Subroutine Documentation
   subroutine dlanv2 (double precisionA, double precisionB, double precisionC, double precisionD, double precisionRT1R, double precisionRT1I,
       double precisionRT2R, double precisionRT2I, double precisionCS, double precisionSN)
       DLANV2

       Purpose:

	    DLANV2 computes the Schur factorization of a real 2-by-2 nonsymmetric
	    matrix in standard form:

		 [ A  B ] = [ CS -SN ] [ AA  BB ] [ CS	SN ]
		 [ C  D ]   [ SN  CS ] [ CC  DD ] [-SN	CS ]

	    where either
	    1) CC = 0 so that AA and DD are real eigenvalues of the matrix, or
	    2) AA = DD and BB*CC < 0, so that AA + or - sqrt(BB*CC) are complex
	    conjugate eigenvalues.

       Parameters:
	   A

		     A is DOUBLE PRECISION

	   B

		     B is DOUBLE PRECISION

	   C

		     C is DOUBLE PRECISION

	   D

		     D is DOUBLE PRECISION
		     On entry, the elements of the input matrix.
		     On exit, they are overwritten by the elements of the
		     standardised Schur form.

	   RT1R

		     RT1R is DOUBLE PRECISION

	   RT1I

		     RT1I is DOUBLE PRECISION

	   RT2R

		     RT2R is DOUBLE PRECISION

	   RT2I

		     RT2I is DOUBLE PRECISION
		     The real and imaginary parts of the eigenvalues. If the
		     eigenvalues are a complex conjugate pair, RT1I > 0.

	   CS

		     CS is DOUBLE PRECISION

	   SN

		     SN is DOUBLE PRECISION
		     Parameters of the rotation matrix.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Further Details:

	     Modified by V. Sima, Research Institute for Informatics, Bucharest,
	     Romania, to reduce the risk of cancellation errors,
	     when computing real eigenvalues, and to ensure, if possible, that
	     abs(RT1R) >= abs(RT2R).

       Definition at line 128 of file dlanv2.f.

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

Version 3.4.1							  Sun May 26 2013						       dlanv2.f(3)