Use gpaw mpi4py (#834)

* mpi4py

* single atom cell

Author: jan-janssen

notebooks/5-1-gpaw.ipynb

@@ -42,13 +42,20 @@
    "outputs": [],
    "source": [
     "def evaluate_with_gpaw(task_dict, kpts, encut):\n",
+    "    import os\n",
+    "    os.environ[\"OMP_NUM_THREADS\"] = \"1\"\n",
+    "    os.environ[\"GPAW_MPI4PY\"] = \"1\"\n",
+    "\n",
+    "    from mpi4py import MPI\n",
     "    from gpaw import GPAW, PW\n",
+    "    from gpaw.mpi4pywrapper import MPI4PYWrapper\n",
     "\n",
     "    structure = task_dict[\"calc_energy\"].copy()\n",
     "    structure.calc = GPAW(\n",
     "        xc=\"PBE\",\n",
     "        mode=PW(encut),\n",
     "        kpts=kpts,\n",
+    "        communicator=MPI4PYWrapper(MPI.COMM_WORLD),\n",
     "    )\n",
     "    return structure.get_potential_energy()"
    ]
@@ -67,7 +74,7 @@
    "outputs": [],
    "source": [
     "task_dict = get_tasks_for_energy_volume_curve(\n",
-    "    structure=bulk(\"Al\", a=4.05, cubic=True),\n",
+    "    structure=bulk(\"Al\", a=4.05),\n",
     "    num_points=7,\n",
     "    vol_range=0.05,\n",
     "    axes=(\"x\", \"y\", \"z\"),\n",
@@ -219,7 +226,7 @@
     "            task_dict=v, \n",
     "            kpts=(3, 3, 3), \n",
     "            encut=300,\n",
-    "            resource_dict={\"cores\": 1},\n",
+    "            resource_dict={\"cores\": 2},\n",
     "        )\n",
     "    sleep(1)\n",
     "    pprint.pp(subprocess.check_output([\"flux\", \"jobs\", \"-a\"], universal_newlines=True).split(\"\\n\"))\n",
@@ -416,7 +423,7 @@
     "            task_dict=v, \n",
     "            kpts=(3, 3, 3), \n",
     "            encut=300,\n",
-    "            resource_dict={\"cores\": 1},\n",
+    "            resource_dict={\"cores\": 2},\n",
     "        )\n",
     "    sleep(1)\n",
     "    pprint.pp(subprocess.check_output([\"flux\", \"jobs\", \"-a\"], universal_newlines=True).split(\"\\n\"))\n",