CCL: Charmm code

From: "jax cho" <cneks2012 .. gmail.com>
Subject: CCL: Charmm code
Date: Thu, 6 Sep 2012 16:31:36 -0400

 Sent to CCL by: "jax  cho" [cneks2012%gmail.com]
 Hello,
 I am reading charmm code and wondering if anyone could give me a hint about
 subrouteine estrbnd of file escalar_mm.
 this subroutine should involve three atoms (idx, jdx and kdx) since it is
 related with one angle. The gradient, however, relates to four atoms, indexed
 with idx,jdx,kdx and additional ldx. Could anyone tell me what this ldx refer
 to?
 Thanks.
 Jax