extract() implementation for dihedral charmm and charmmfsw

doc/src/fix_adapt.rst

@@ -457,6 +457,10 @@ all types from 1 to :math:`N`.  A leading asterisk means all types from
 If :doc:`dihedral_style hybrid <dihedral_hybrid>` is used, *dstyle* should be a
 sub-style name. The dihedral styles that currently work with fix adapt are:
 
++------------------------------------------------------------------------+----------------+----------------+
+| :doc:`charmm  <dihedral_charmm>`                                       | k,n,d          | type dihedrals |
++------------------------------------------------------------------------+----------------+----------------+
+| :doc:`charmmfsw <dihedral_charmm>`                                     | k,n,d          | type dihedrals |
 +------------------------------------------------------------------------+----------------+----------------+
 | :doc:`cosine/squared/restricted <dihedral_cosine_squared_restricted>`  | k,phi0         | type dihedrals |
 +------------------------------------------------------------------------+----------------+----------------+

src/MOLECULE/dihedral_charmm.cpp

@@ -432,3 +432,16 @@ void DihedralCharmm::write_data(FILE *fp)
   for (int i = 1; i <= atom->ndihedraltypes; i++)
     fprintf(fp, "%d %g %d %d %g\n", i, k[i], multiplicity[i], shift[i], weight[i]);
 }
+
+ /* ----------------------------------------------------------------------
+    return ptr to internal members upon request
+ ------------------------------------------------------------------------ */
+ 
+ void *DihedralCharmm::extract(const char *str, int &dim)
+ {
+   dim = 1;
+   if (strcmp(str, "k") == 0) return (void *) k0;
+   if (strcmp(str, "n") == 0) return (void *) multiplicity;
+   if (strcmp(str, "d") == 0) return (void *) shift;
+   return nullptr;
+ }

src/MOLECULE/dihedral_charmm.h

@@ -34,6 +34,7 @@ class DihedralCharmm : public Dihedral {
   void write_restart(FILE *) override;
   void read_restart(FILE *) override;
   void write_data(FILE *) override;
+  void *extract(const char *, int &) override;
 
  protected:
   double *k, *weight, *cos_shift, *sin_shift;

src/MOLECULE/dihedral_charmmfsw.cpp

@@ -475,3 +475,16 @@ void DihedralCharmmfsw::write_data(FILE *fp)
   for (int i = 1; i <= atom->ndihedraltypes; i++)
     fprintf(fp, "%d %g %d %d %g\n", i, k[i], multiplicity[i], shift[i], weight[i]);
 }
+
+ /* ----------------------------------------------------------------------
+    return ptr to internal members upon request
+ ------------------------------------------------------------------------ */
+ 
+ void *DihedralCharmmfsw::extract(const char *str, int &dim)
+ {
+   dim = 1;
+   if (strcmp(str, "k") == 0) return (void *) k0;
+   if (strcmp(str, "n") == 0) return (void *) multiplicity;
+   if (strcmp(str, "d") == 0) return (void *) shift;
+   return nullptr;
+ }

src/MOLECULE/dihedral_charmmfsw.h

@@ -34,6 +34,7 @@ class DihedralCharmmfsw : public Dihedral {
   void write_restart(FILE *) override;
   void read_restart(FILE *) override;
   void write_data(FILE *) override;
+  void *extract(const char *, int &) override;
 
  protected:
   int implicit, weightflag, dihedflag;

unittest/force-styles/tests/dihedral-charmm.yaml

@@ -19,7 +19,10 @@ dihedral_coeff: ! |
   3  56.0 0 110 0.0
   4  23.0 1 180 0.5
   5  19.0 3  90 1.0
-extract: ! ""
+extract: ! |
+  k 1
+  n 1
+  d 1
 natoms: 29
 init_energy: 1317.959844120986
 init_stress: ! |2-

unittest/force-styles/tests/dihedral-charmmfsw.yaml

@@ -19,7 +19,10 @@ dihedral_coeff: ! |
   3  56.0 0 110 0.0
   4  23.0 1 180 0.5
   5  19.0 3  90 1.0
-extract: ! ""
+extract: ! |
+  k 1
+  n 1
+  d 1
 natoms: 29
 init_energy: 1317.959844120986
 init_stress: ! |2-