void tran( double ax ,double ay ,double az ,double x ,double y ,double z ,double xt ,double yt ,double zt ){
    double sinx ,siny ,sinz ,cosx ,cosy ,cosz ;
    xt = x * ( cosy * cosz - sinx * siny * sinz ) 
       - y * cosx * sinz 
       + z * ( siny * cosz + sinx * cosy * sinz ) ;
    yt = x * ( cosy * sinz + sinx * siny * cosz )
       + y * cosx * cosz
       + z * ( siny * sinz - sinx * cosy * cosz ) ;
    zt = x * ( -cosx * siny )
       + y * sinx 
       + z * cosx * cosy ;
    return ;
}