elements_father(src, dst, &common_father, &src_father, &dst_father);
XBT_DEBUG("elements_father: common father '%s' src_father '%s' dst_father '%s'",
common_father->p_name, src_father->p_name, dst_father->p_name);
elements_father(src, dst, &common_father, &src_father, &dst_father);
XBT_DEBUG("elements_father: common father '%s' src_father '%s' dst_father '%s'",
common_father->p_name, src_father->p_name, dst_father->p_name);