adding parakat example

examples/parallel_running.py

+# Example on running multiple kat objects at once using the parakat feature.
+#
+# Firstly you need to start an ipython cluster on your computer. To do this open
+# a new terminal and type the command:
+#
+#   ipcluster start -n 4
+#
+# This will start a cluster with 4 workers. You should set this number to how many
+# cores you have.
+#
+
+import pykat
+from pykat.parallel import parakat
+
+# Create a connection to the server
+pk = parakat()
+
+# Create a bunch of kat objects to run
+kat1 = pykat.finesse.kat()
+kat2 = pykat.finesse.kat()
+kat3 = pykat.finesse.kat()
+
+kat1.parseCommands("""
+l l1 1 0 n0
+s s1 1 n0 n1
+pd P n1
+noxaxis
+""")
+
+kat2.parseCommands("""
+l l1 2 0 n0
+s s1 1 n0 n1
+pd P n1
+noxaxis
+""")
+
+kat3.parseCommands("""
+l l1 3 0 n0
+s s1 1 n0 n1
+pd P n1
+noxaxis
+""")
+
+# Each kat object that is started straightaway when called like this.
+# You can add as many as you want, the number that will
+# run at once depends on the number of workers in the cluster
+pk.run(kat1, cmd_args=["-cr=on"])
+pk.run(kat2, cmd_args=["-cr=on"])
+pk.run(kat3, cmd_args=["-cr=on"])
+
+# Now you can get the output objects for each of the files run
+# They will be returned in order. So you can get each of the outputs using:
+out1, out2, out3 = pk.getResults()
+
+print(out1["P"])
+print(out2["P"])
+print(out3["P"])
+
+# or you could also get the outputs in a list:
+outs = pk.getResults()
+# so you'd then access the ouputs like: outs[0], outs[1], etc.
+# This option is useful if you want to iterate over each output
+# result in a for loop for example:
+
+for out in outs:
+    print(out["P"])
+
+# Call `clear` to remove the last output results
+# After this you could run more in parallel and get the outputs
+# for those.
+pk.clear()
+
+# When finally done you should close the connection to the cluster
+pk.close()

pykat/parallel.py

@@ -89,8 +89,8 @@ class parakat(object):
         return out
     
     def clear(self):
-        del(self._result)
-        self._result = []
+        del(self._results)
+        self._results = []
     
     def close(self):
         self._rc.close()