la_lapack::lartg Interface Reference

! More...

Public Member Functions
pure subroutine	clartg (f, g, c, s, r)
	la_clartg
pure subroutine	dlartg (f, g, c, s, r)
	la_dlartg
	la_qlartg
pure subroutine	slartg (f, g, c, s, r)
	la_slartg
	la_wlartg
pure subroutine	zlartg (f, g, c, s, r)
	la_zlartg

Detailed Description

!

LARTG: generates a plane rotation so that [ C S ] . [ F ] = [ R ] [ -conjg(S) C ] [ G ] [ 0 ] where C is real and C**2 + |S|**2 = 1. The mathematical formulas used for C and S are sgn(x) = { x / |x|, x != 0 { 1, x = 0 R = sgn(F) * sqrt(|F|**2 + |G|**2) C = |F| / sqrt(|F|**2 + |G|**2) S = sgn(F) * conjg(G) / sqrt(|F|**2 + |G|**2) When F and G are real, the formulas simplify to C = F/R and S = G/R, and the returned values of C, S, and R should be identical to those returned by LARTG. The algorithm used to compute these quantities incorporates scaling to avoid overflow or underflow in computing the square root of the sum of squares. This is a faster version of the BLAS1 routine CROTG, except for the following differences: F and G are unchanged on return. If G=0, then C=1 and S=0. If F=0, then C=0 and S is chosen so that R is real. Below, wp=>sp stands for single precision from LA_CONSTANTS module.

Member Function/Subroutine Documentation

clartg()

pure subroutine la_lapack::lartg::clartg	(	complex(sp), intent(in)	f,
		complex(sp), intent(in)	g,
		real(sp), intent(out)	c,
		complex(sp), intent(out)	s,
		complex(sp), intent(out)	r
	)

dlartg()

pure subroutine la_lapack::lartg::dlartg	(	real(dp), intent(in)	f,
		real(dp), intent(in)	g,
		real(dp), intent(out)	c,
		real(dp), intent(out)	s,
		real(dp), intent(out)	r
	)

la_clartg()

la_lapack::lartg::la_clartg

la_dlartg()

la_lapack::lartg::la_dlartg

la_qlartg()

la_lapack::lartg::la_qlartg

la_slartg()

la_lapack::lartg::la_slartg

la_wlartg()

la_lapack::lartg::la_wlartg

la_zlartg()

la_lapack::lartg::la_zlartg

slartg()

pure subroutine la_lapack::lartg::slartg	(	real(sp), intent(in)	f,
		real(sp), intent(in)	g,
		real(sp), intent(out)	c,
		real(sp), intent(out)	s,
		real(sp), intent(out)	r
	)

zlartg()

pure subroutine la_lapack::lartg::zlartg	(	complex(dp), intent(in)	f,
		complex(dp), intent(in)	g,
		real(dp), intent(out)	c,
		complex(dp), intent(out)	s,
		complex(dp), intent(out)	r
	)

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The documentation for this interface was generated from the following file:

• la_lapack.f90