stdlib_srotmg Subroutine

public pure subroutine stdlib_srotmg(sd1, sd2, sx1, sy1, sparam)

SROTMG Constructs the modified Givens transformation matrix $H$ which zeros the second component of the 2-vector $$\left[ {\sqrt{SD_1}\cdot SX_1,\sqrt{SD_2}\cdot SY_2} \right]^T.$$ With SPARAM(1)=SFLAG, $H$ has one of the following forms:
$$H=\underbrace{\begin{bmatrix}SH_{11} & SD_{12}\\SH_{21} & SH_{22}\end{bmatrix}}_{SFLAG=-1}, \underbrace{\begin{bmatrix}1 & SH_{12}\\SH_{21} & 1\end{bmatrix}}_{SFLAG=0}, \underbrace{\begin{bmatrix}SH_{11} & 1\\-1 & SH_{22}\end{bmatrix}}_{SFLAG=1}, \underbrace{\begin{bmatrix}1 & 0\\0 & 1\end{bmatrix}}_{SFLAG=2}.$$ Locations 2-4 of SPARAM contain SH11, SH21, SH12 and SH22 respectively. (Values of 1.0, -1.0, or 0.0 implied by the value of SPARAM(1) are not stored in SPARAM.) The values of parameters GAMSQ and RGAMSQ may be inexact. This is OK as they are only used for testing the size of DD1 and DD2. All actual scaling of data is done using GAM.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=sp),	intent(inout)			::	sd1
real(kind=sp),	intent(inout)			::	sd2
real(kind=sp),	intent(inout)			::	sx1
real(kind=sp),	intent(in)			::	sy1
real(kind=sp),	intent(out)			::	sparam(5)