dlartgs.f - Man Page
SRC/dlartgs.f
Synopsis
Functions/Subroutines
subroutine dlartgs (x, y, sigma, cs, sn)
DLARTGS generates a plane rotation designed to introduce a bulge in implicit QR iteration for the bidiagonal SVD problem.
Function/Subroutine Documentation
subroutine dlartgs (double precision x, double precision y, double precision sigma, double precision cs, double precision sn)
DLARTGS generates a plane rotation designed to introduce a bulge in implicit QR iteration for the bidiagonal SVD problem.
Purpose:
DLARTGS 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 DOUBLE PRECISION The (1,1) entry of an upper bidiagonal matrix.
Y
Y is DOUBLE PRECISION The (1,2) entry of an upper bidiagonal matrix.
SIGMA
SIGMA is DOUBLE PRECISION The shift.
CS
CS is DOUBLE PRECISION The cosine of the rotation.
SN
SN is DOUBLE PRECISION 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 dlartgs.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page dlartgs(3) is an alias of dlartgs.f(3).
Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK