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 (real X, real Y, real SIGMA, real CS, real SN)
       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

Author

       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.6.0                                    Sun Jan 17 2016                                    slartgs.f(3)