Main
Development
Information
Community
Social media
Other
  1. Manuals
  2. Leap-16.0
  3. lapack-man
  4. slartgs.f(3)

Scroll to navigation

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/slartgs.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/slartgs.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/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.

Definition at line 89 of file slartgs.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Version 3.12.0 LAPACK