drotmg

NAME

drotmg - Construct a Gentleman's modified Given's plane rotation

SYNOPSIS

  SUBROUTINE DROTMG( D1, D2, B1, B2, PARAM)
  DOUBLE PRECISION D1, D2, B1, B2
  DOUBLE PRECISION PARAM(*)
 
  SUBROUTINE DROTMG_64( D1, D2, B1, B2, PARAM)
  DOUBLE PRECISION D1, D2, B1, B2
  DOUBLE PRECISION PARAM(*)

F95 INTERFACE

  SUBROUTINE ROTMG( D1, D2, B1, B2, PARAM)
  REAL(8) :: D1, D2, B1, B2
  REAL(8), DIMENSION(:) :: PARAM
 
  SUBROUTINE ROTMG_64( D1, D2, B1, B2, PARAM)
  REAL(8) :: D1, D2, B1, B2
  REAL(8), DIMENSION(:) :: PARAM

C INTERFACE

#include <sunperf.h>

void drotmg(double d1, double d2, double b1, double b2, double *param);

void drotmg_64(double d1, double d2, double b1, double b2, double *param);

PURPOSE

drotmg Construct Gentleman's modified a Given's plane rotation that will annihilate an element of a vector.

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/output): On entry, the second element of the vector to which the H matrix is applied. On exit, changed to reflect the effect of the transformation.
* PARAM (input/output): On entry, PARAM(1) describes the form of the H matrix. On exit, PARAM(2..5) contain the H matrix.