Set up options to select driver

drivers/py/driver.py

@@ -9,6 +9,7 @@
 Minimal example of a Python driver connecting to i-PI and exchanging energy, forces, etc.
 """
 
+
 def recv_data(sock, data):
     """Fetches binary data from i-PI socket."""
     blen = data.itemsize * data.size

ipi/engine/forcefields.py

@@ -23,6 +23,7 @@
 from ipi.utils.io import read_file
 from ipi.utils.units import unit_to_internal
 from ipi.utils.distance import vector_separation
+from ipi.pes import __drivers__
 
 try:
     import plumed
@@ -392,7 +393,42 @@ def evaluate(self, request):
 
 
 class FFDirect(FFEval):
-    pass
+    def __init__(
+        self,
+        latency=1.0,
+        offset=0.0,
+        name="",
+        pars=None,
+        dopbc=False,
+        active=np.array([-1]),
+        threaded=False,
+        pes="dummy",
+    ):
+        """Initialises FFDirect.
+
+        Args:
+            latency: The number of seconds the socket will wait before updating
+                the client list.
+            offset: A constant offset subtracted from the energy value given by the
+                client.
+            name: The name of the forcefield.
+            pars: A dictionary used to initialize the forcefield, if required.
+                Of the form {'name1': value1, 'name2': value2, ... }.
+            dopbc: Decides whether or not to apply the periodic boundary conditions
+                before sending the positions to the client code.
+            active: Indexes of active atoms in this forcefield
+
+        """
+
+        super().__init__(latency, offset, name, pars, dopbc, active, threaded)
+
+        self.pes = pes
+        # TODO sanitize the handling of pars
+        self.driver = __drivers__[self.pes]("", verbosity.high)
+
+    def evaluate(self, request):
+        request["result"] = list(self.driver(request["cell"][0], request["pos"]))
+        request["status"] = "Done"
 
 
 class FFLennardJones(FFEval):

ipi/inputs/forcefields.py

@@ -22,6 +22,7 @@
     FFCavPhSocket,
 )
 from ipi.interfaces.sockets import InterfaceSocket
+from ipi.pes import __drivers__
 import ipi.engine.initializer
 from ipi.inputs.initializer import *
 from ipi.utils.inputvalue import *
@@ -341,14 +342,42 @@ def check(self):
 
 
 class InputFFDirect(InputForceField):
+    fields = {
+        "pes": (
+            InputValue,
+            {
+                "dtype": str,
+                "default": "dummy",
+                "options": list(__drivers__.keys()),
+                "help": "Type of PES that should be used to evaluate the forcefield",
+            },
+        ),
+    }
+    fields.update(InputForceField.fields)
+
     attribs = {}
     attribs.update(InputForceField.attribs)
 
     default_help = """ Direct potential that evaluates forces through a Python
     call, using PES providers from a list of possible external codes. """
     default_label = "FFDirect"
 
-    _FFCLASS = FFDirect
+    def store(self, ff):
+        super().store(ff)
+        self.pes.store(ff.pes)
+
+    def fetch(self):
+        super().fetch()
+
+        return FFDirect(
+            pars=self.parameters.fetch(),
+            name=self.name.fetch(),
+            latency=self.latency.fetch(),
+            offset=self.offset.fetch(),
+            dopbc=self.pbc.fetch(),
+            threaded=self.threaded.fetch(),
+            pes=self.pes.fetch(),
+        )
 
 
 class InputFFLennardJones(InputForceField):
@@ -438,7 +467,7 @@ class InputFFDebye(InputForceField):
                 "default": input_default(factory=np.zeros, args=(0,)),
                 "help": "Specifies the Hessian of the harmonic potential. "
                 "Default units are atomic. Units can be specified only by xml attribute. "
-                "Implemented options are: 'atomic_unit', 'ev/ang\^2'",
+                r"Implemented options are: 'atomic_unit', 'ev/ang^2'",
                 "dimension": "hessian",
             },
         ),

ipi_tests/profiling/classical_md_direct/input.xml

@@ -1,5 +1,6 @@
 <simulation verbosity='medium' threading='false' safe_stride='100'>
-   <ffdirect name='driver'>
+    <ffdirect name='driver'>
+        <pes> dummy </pes>  
       <latency>  1.00000000e-04</latency>
    </ffdirect>
    <total_steps>10000</total_steps>