(S|D)ROTMG¶

Single and double ROTMG.

Description¶

Generate a single modified plane rotation.

$H * \left[ \begin{array}{c} \sqrt{D_1}\mult X_1 \\ \sqrt{D_2}\mult Y_1 \end{array} \right] = \left[ \begin{array}{c} R \\ 0 \end{array} \right]$

The form of the generated rotation matrix H will depend on FLAG which is the first element of the PARAM input array.

$\fvar{PARAM} = \left[ \begin{array}{c} \fvar{FLAG} \\ \fvar{H11} \\ \fvar{H21} \\ \fvar{H12} \\ \fvar{H22} \end{array} \right]$

If $\fvar{FLAG}=-1$ :

$H = \left[ \begin{array}{ll} \fvar{H11} & \fvar{H12} \\ \fvar{H21} & \fvar{H22} \\ \end{array} \right]$

If $\fvar{FLAG}=0$ :

$H = \left[ \begin{array}{ll} 1 & \fvar{H12} \\ \fvar{H21} & 1 \\ \end{array} \right]$

If $\fvar{FLAG}=1$ :

$H = \left[ \begin{array}{ll} \fvar{H11} & 1 \\ -1 & \fvar{H22} \\ \end{array} \right]$

If $\fvar{FLAG}=-2$ :

$H = \left[ \begin{array}{ll} 1 & 0 \\ 0 & 1 \\ \end{array} \right]$

BLAS Interface¶

void srotmg(float *D1, float *D2, float *X1, const float *Y1, float *PARAM);

void drotmg(double *D1, double *D2, double *X1, const double *Y1,
            double *PARAM);

CBLAS Interface¶

void cblas_srotmg(float *D1, float *D2, float *X1, const float Y1,
                  float *PARAM);

void cblas_drotmg(double *D1, double *D2, double *X1, const double Y1,
                  double *PARAM);

Arguments¶

D1	First scaling factor
D2	Second scaling factor
X1	First component of vector to rotate
Y1	Second component of vector to rotate
PARAM	Rotation parameter array of length 5