Merge remote-tracking branch 'github/develop' into python_computes

python/lammps/core.py

@@ -103,7 +103,7 @@ class command_wrapper(object):
     This method is where the Python 'magic' happens. If a method is not
     defined by the class command_wrapper, it assumes it is a LAMMPS command. It takes
     all the arguments, concatinates them to a single string, and executes it using
-    :py:meth:`lammps.command()`.
+    :py:meth:`lammps.command`.
 
     Starting with Python 3.6 it also supports keyword arguments. key=value is
     transformed into 'key value'. Note, since these have come last in the
@@ -426,6 +426,9 @@ class lammps(object):
     self.lib.lammps_compute_addstep.argtype = [c_void_p, self.c_bigint]
     self.lib.lammps_compute_addstep_all.argtype = [c_void_p, self.c_bigint]
 
+    self.lib.lammps_eval.argtypes = [c_void_p, c_char_p]
+    self.lib.lammps_eval.restype = c_double
+
     self.lib.lammps_fix_external_get_force.argtypes = [c_void_p, c_char_p]
     self.lib.lammps_fix_external_get_force.restype = POINTER(POINTER(c_double))
 
@@ -1693,6 +1696,30 @@ class lammps(object):
 
   # -------------------------------------------------------------------------
 
+  def eval(self, expr):
+    """ Evaluate a LAMMPS immediate variable expression
+
+    .. versionadded:: TBD
+
+    This function is a wrapper around the function :cpp:func:`lammps_eval`
+    of the C library interface.  It evaluates and expression like in
+    immediate variables and returns the value.
+
+    :param expr: immediate variable expression
+    :type name: string
+    :return: the result of the evaluation
+    :rtype: c_double
+    """
+
+    if expr: newexpr = expr.encode()
+    else: return None
+
+    with ExceptionCheck(self):
+      return self.lib.lammps_eval(self.lmp, newexpr)
+    return None
+
+  # -------------------------------------------------------------------------
+
   # return vector of atom properties gathered across procs
   # 3 variants to match src/library.cpp
   # name = atom property recognized by LAMMPS in atom->extract()

python/lammps/ipython/wrapper.py

@@ -17,7 +17,7 @@
 ################################################################################
 
 class wrapper(object):
-  """lammps API IPython Wrapper
+  """ lammps API IPython Wrapper
 
   This is a wrapper class that provides additional methods on top of an
   existing :py:class:`lammps` instance. It provides additional methods