lartgp: generate plane rotation, more accurate than BLAS rot

Functions
subroutine	dlartgp (f, g, cs, sn, r)
	DLARTGP generates a plane rotation so that the diagonal is nonnegative.
subroutine	slartgp (f, g, cs, sn, r)
	SLARTGP generates a plane rotation so that the diagonal is nonnegative.

Detailed Description