slartgs.f(3) [centos man page]

slartgs.f(3)							      LAPACK							      slartgs.f(3)

NAME

       slartgs.f -

SYNOPSIS

   Functions/Subroutines
       subroutine slartgs (X, Y, SIGMA, CS, SN)
	   SLARTGS generates a plane rotation designed to introduce a bulge in implicit QR iteration for the bidiagonal SVD problem.

Function/Subroutine Documentation
   subroutine slartgs (realX, realY, realSIGMA, realCS, realSN)
       SLARTGS generates a plane rotation designed to introduce a bulge in implicit QR iteration for the bidiagonal SVD problem.

       Purpose:

	    SLARTGS generates a plane rotation designed to introduce a bulge in
	    Golub-Reinsch-style implicit QR iteration for the bidiagonal SVD
	    problem. X and Y are the top-row entries, and SIGMA is the shift.
	    The computed CS and SN define a plane rotation satisfying

	       [  CS  SN  ]  .	[ X^2 - SIGMA ]  =  [ R ],
	       [ -SN  CS  ]	[    X * Y    ]     [ 0 ]

	    with R nonnegative.  If X^2 - SIGMA and X * Y are 0, then the
	    rotation is by PI/2.

       Parameters:
	   X

		     X is REAL
		     The (1,1) entry of an upper bidiagonal matrix.

	   Y

		     Y is REAL
		     The (1,2) entry of an upper bidiagonal matrix.

	   SIGMA

		     SIGMA is REAL
		     The shift.

	   CS

		     CS is REAL
		     The cosine of the rotation.

	   SN

		     SN is REAL
		     The sine of the rotation.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Definition at line 91 of file slartgs.f.

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

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

slartgp.f(3)							      LAPACK							      slartgp.f(3)

NAME

       slartgp.f -

SYNOPSIS

   Functions/Subroutines
       subroutine slartgp (F, G, CS, SN, R)
	   SLARTGP generates a plane rotation so that the diagonal is nonnegative.

Function/Subroutine Documentation
   subroutine slartgp (realF, realG, realCS, realSN, realR)
       SLARTGP generates a plane rotation so that the diagonal is nonnegative.

       Purpose:

	    SLARTGP generates a plane rotation so that

	       [  CS  SN  ]  .	[ F ]  =  [ R ]   where CS**2 + SN**2 = 1.
	       [ -SN  CS  ]	[ G ]	  [ 0 ]

	    This is a slower, more accurate version of the Level 1 BLAS routine SROTG,
	    with the following other differences:
	       F and G are unchanged on return.
	       If G=0, then CS=(+/-)1 and SN=0.
	       If F=0 and (G .ne. 0), then CS=0 and SN=(+/-)1.

	    The sign is chosen so that R >= 0.

       Parameters:
	   F

		     F is REAL
		     The first component of vector to be rotated.

	   G

		     G is REAL
		     The second component of vector to be rotated.

	   CS

		     CS is REAL
		     The cosine of the rotation.

	   SN

		     SN is REAL
		     The sine of the rotation.

	   R

		     R is REAL
		     The nonzero component of the rotated vector.

	     This version has a few statements commented out for thread safety
	     (machine parameters are computed on each entry). 10 feb 03, SJH.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Definition at line 96 of file slartgp.f.

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

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