CentOS 7.0 - man page for dlasv2 (centos section 3)

Linux & Unix Commands - Search Man Pages

Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


dlasv2.f(3)				      LAPACK				      dlasv2.f(3)

NAME
       dlasv2.f -

SYNOPSIS
   Functions/Subroutines
       subroutine dlasv2 (F, G, H, SSMIN, SSMAX, SNR, CSR, SNL, CSL)
	   DLASV2 computes the singular value decomposition of a 2-by-2 triangular matrix.

Function/Subroutine Documentation
   subroutine dlasv2 (double precisionF, double precisionG, double precisionH, double
       precisionSSMIN, double precisionSSMAX, double precisionSNR, double precisionCSR, double
       precisionSNL, double precisionCSL)
       DLASV2 computes the singular value decomposition of a 2-by-2 triangular matrix.

       Purpose:

	    DLASV2 computes the singular value decomposition of a 2-by-2
	    triangular matrix
	       [  F   G  ]
	       [  0   H  ].
	    On return, abs(SSMAX) is the larger singular value, abs(SSMIN) is the
	    smaller singular value, and (CSL,SNL) and (CSR,SNR) are the left and
	    right singular vectors for abs(SSMAX), giving the decomposition

	       [ CSL  SNL ] [  F   G  ] [ CSR -SNR ]  =  [ SSMAX   0   ]
	       [-SNL  CSL ] [  0   H  ] [ SNR  CSR ]	 [  0	 SSMIN ].

       Parameters:
	   F

		     F is DOUBLE PRECISION
		     The (1,1) element of the 2-by-2 matrix.

	   G

		     G is DOUBLE PRECISION
		     The (1,2) element of the 2-by-2 matrix.

	   H

		     H is DOUBLE PRECISION
		     The (2,2) element of the 2-by-2 matrix.

	   SSMIN

		     SSMIN is DOUBLE PRECISION
		     abs(SSMIN) is the smaller singular value.

	   SSMAX

		     SSMAX is DOUBLE PRECISION
		     abs(SSMAX) is the larger singular value.

	   SNL

		     SNL is DOUBLE PRECISION

	   CSL

		     CSL is DOUBLE PRECISION
		     The vector (CSL, SNL) is a unit left singular vector for the
		     singular value abs(SSMAX).

	   SNR

		     SNR is DOUBLE PRECISION

	   CSR

		     CSR is DOUBLE PRECISION
		     The vector (CSR, SNR) is a unit right singular vector for the
		     singular value abs(SSMAX).

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Further Details:

	     Any input parameter may be aliased with any output parameter.

	     Barring over/underflow and assuming a guard digit in subtraction, all
	     output quantities are correct to within a few units in the last
	     place (ulps).

	     In IEEE arithmetic, the code works correctly if one matrix element is
	     infinite.

	     Overflow will not occur unless the largest singular value itself
	     overflows or is within a few ulps of overflow. (On machines with
	     partial overflow, like the Cray, overflow may occur if the largest
	     singular value is within a factor of 2 of overflow.)

	     Underflow is harmless if underflow is gradual. Otherwise, results
	     may correspond to a matrix modified by perturbations of size near
	     the underflow threshold.

       Definition at line 139 of file dlasv2.f.

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

Version 3.4.2				 Tue Sep 25 2012			      dlasv2.f(3)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 11:08 AM.

Unix & Linux Forums Content Copyright©1993-2018. All Rights Reserved.
×
UNIX.COM Login
Username:
Password:  
Show Password





Not a Forum Member?
Forgot Password?