lartgs Interface

public interface lartgs

LARTGS 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.


Subroutines

public pure subroutine dlartgs(x, y, sigma, cs, sn)

Arguments

Type IntentOptional Attributes Name
real(kind=dp), intent(in) :: x
real(kind=dp), intent(in) :: y
real(kind=dp), intent(in) :: sigma
real(kind=dp), intent(out) :: cs
real(kind=dp), intent(out) :: sn

public pure subroutine slartgs(x, y, sigma, cs, sn)

Arguments

Type IntentOptional Attributes Name
real(kind=sp), intent(in) :: x
real(kind=sp), intent(in) :: y
real(kind=sp), intent(in) :: sigma
real(kind=sp), intent(out) :: cs
real(kind=sp), intent(out) :: sn

Module Procedures

public interface stdlib_slartgs()

Arguments

None

public interface stdlib_dlartgs()

Arguments

None