Provided by: liblapack-doc_3.3.1-1_all bug

NAME

       LAPACK-3 - generates a plane rotation designed to introduce a bulge in Golub-Reinsch-style
       implicit QR iteration for the bidiagonal SVD problem

SYNOPSIS

       SUBROUTINE SLARTGS( X, Y, SIGMA, CS, SN )

           IMPLICIT        NONE

           REAL            CS, SIGMA, SN, X, Y

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.

ARGUMENTS

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

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

        SIGMA   (input) REAL
                The shift.

        CS      (output) REAL
                The cosine of the rotation.

        SN      (output) REAL
                The sine of the rotation.

 LAPACK routine (version 3.3.0)             April 2011                           SLARTGS(3lapack)