rotmat()

void rotmat	(	COMPLEX *	c,
		COMPLEX *	s,
		const COMPLEX	a,
		const COMPLEX	b
	)

{

   COMPLEX temp;
 if ( b == 0.0 ){
   *c = 1.0 + I*0.0;
   *s = 0.0 + I*0.0;
 }else if ( cabs(b) > cabs(a) ){
   temp = a / b;
   *s = 1.0 / csqrt( 1.0 + temp*temp );
   *c = temp * (*s);
 }else{
   temp = b / a;
   *c = 1.0 / csqrt( 1.0 + temp*temp );
   *s = temp * (*c);
 }

}