srotmg(3P) Sun Performance Library srotmg(3P)NAMEsrotmg - Construct a Gentleman's modified Given's plane rotation
SYNOPSIS
SUBROUTINE SROTMG(D1, D2, B1, B2, PARAM)
REAL D1, D2, B1, B2
REAL PARAM(*)
SUBROUTINE SROTMG_64(D1, D2, B1, B2, PARAM)
REAL D1, D2, B1, B2
REAL PARAM(*)
F95 INTERFACE
SUBROUTINE ROTMG(D1, D2, B1, B2, PARAM)
REAL :: D1, D2, B1, B2
REAL, DIMENSION(:) :: PARAM
SUBROUTINE ROTMG_64(D1, D2, B1, B2, PARAM)
REAL :: D1, D2, B1, B2
REAL, DIMENSION(:) :: PARAM
C INTERFACE
#include <sunperf.h>
void srotmg(float d1, float d2, float b1, float b2, float *param);
void srotmg_64(float d1, float d2, float b1, float b2, float *param);
PURPOSEsrotmg constructs the modified givens transformation matrix h which
zeros the second component of the 2-vector
(SQRT(D1)*B1,SQRT(D2)*B2)**T.
ARGUMENTS
D1 (input/output)
On entry, the first diagonal entry in the H matrix. On exit,
changed to reflect the effect of the transformation.
D2 (input/output)
On entry, the second diagonal entry in the H matrix. On
exit, changed to reflect the effect of the transformation.
B1 (input/output)
On entry, the first element of the vector to which the H
matrix is applied. On exit, changed to reflect the effect of
the transformation.
B2 (input)
On entry, the second element of the vector to which the H
matrix is applied. Unchanged on exit.
PARAM (output)
On exit, PARAM(1) describes the form of the rotation matrix
H, and PARAM(2..5) contain the H matrix.
If PARAM(1) = -2 then H = I and no elements of PARAM are mod‐
ified.
If PARAM(1) = -1 then PARAM(2) = h11, PARAM(3) = h21,
PARAM(4) = h12, and PARAM(5) = h22.
If PARAM(1) = 0 then h11 = h22 = 1, PARAM(3) = h21, and
PARAM(4) = h12.
If PARAM(1) = 1 then h12 = 1, h21 = -1, PARAM(2) = h11, and
PARAM(5) = h22.
14 Apr 2009 srotmg(3P)
