mods to fix numdiff

src/fix_numdiff.h

@@ -0,0 +1,77 @@
+/* -*- c++ -*- ----------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   http://lammps.sandia.gov, Sandia National Laboratories
+   Steve Plimpton, sjplimp@sandia.gov
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+#ifdef FIX_CLASS
+
+FixStyle(numdiff,FixNumDiff)
+
+#else
+
+#ifndef LMP_FIX_NUMDIFF_H
+#define LMP_FIX_NUMDIFF_H
+
+#include "fix.h"
+
+namespace LAMMPS_NS {
+
+class FixNumDiff : public Fix {
+ public:
+  FixNumDiff(class LAMMPS *, int, char **);
+  ~FixNumDiff();
+  int setmask();
+  void init();
+  void post_force(int);
+  void post_force_respa(int, int, int);
+  void min_post_force(int);
+  double memory_usage();
+
+private:
+  double delta;
+  int maxatom;
+  int ilevel_respa;
+
+  int pair_compute_flag;            // 0 if pair->compute is skipped
+  int kspace_compute_flag;          // 0 if kspace->compute is skipped
+
+  char *id_pe;
+  class Compute *pe;
+
+  double **numdiff_forces;          // finite diff forces
+  double **temp_f;                  // original forces
+  double **temp_x;                  // original coords
+
+  double update_energy(int vflag);
+  void force_clear(double **forces);
+  void create_groupmap();
+  void displace_atom(int local_idx, int direction, int magnitude);
+  void calculate_forces(int vflag);
+};
+
+}
+
+#endif
+#endif
+
+/* ERROR/WARNING messages:
+
+E: Illegal ... command
+
+Self-explanatory.  Check the input script syntax and compare to the
+documentation for the command.  You can use -echo screen as a
+command-line option when running LAMMPS to see the offending line.
+
+E: Compute ID for fix numdiff does not exist
+
+Self-explanatory.
+
+*/