git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@15174 f3b2605a-c512-4ea7-a41b-209d697bcdaa

src/fix_spring_chunk.h

@@ -0,0 +1,78 @@
+/* -*- 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(spring/chunk,FixSpringChunk)
+
+#else
+
+#ifndef LMP_FIX_SPRING_CHUNK_H
+#define LMP_FIX_SPRING_CHUNK_H
+
+#include "fix.h"
+
+namespace LAMMPS_NS {
+
+class FixSpringChunk : public Fix {
+ public:
+  FixSpringChunk(class LAMMPS *, int, char **);
+  ~FixSpringChunk();
+  int setmask();
+  void init();
+  void setup(int);
+  void min_setup(int);
+  void post_force(int);
+  void post_force_respa(int, int, int);
+  void min_post_force(int);
+  double compute_scalar();
+
+ private:
+  int nlevels_respa;
+  double k_spring;
+  double esprings;
+  char *idchunk,*idcom;
+
+  int nchunk;
+  double **com0,**fcom;
+
+  class ComputeChunkAtom *cchunk;
+  class ComputeCOMChunk *ccom;
+};
+
+}
+
+#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: R0 < 0 for fix spring command
+
+Equilibrium spring length is invalid.
+
+E: Fix spring couple group ID does not exist
+
+Self-explanatory.
+
+E: Two groups cannot be the same in fix spring couple
+
+Self-explanatory.
+
+*/