fixing beam trace code of py2->py3 errors

examples/beam_trace.py

+import pykat
+from pykat.tools.plotting.beamtrace import plot_beam_trace
+import numpy as np
+import pylab
+import copy
+
+kat = pykat.finesse.kat()
+
+cmds = """
+l l1 1 0 n0
+s s0 1000 n0 n1
+m m1 0.5 0.5 0 n1 n2
+s s1 10 n2 n3
+m m2 0.5 0.5 0 n3 n4
+s s2 20 n4 n5
+bs bs1 0.5 0.5 0 0 n5 n6 n7 n8
+
+s s3 20 n6 n9
+
+s s4 20 n7 n10
+
+s s5 20 n8 n11
+
+bs bs2 0.5 0.5 0 0 n9 n12 n13 n14
+
+s s6 3 n12 n15
+
+lens lens1 20 n15 n16
+
+s s7 500 n16 n17
+
+gouy g1 x s0 s1 s2
+
+bp bp1 x w0 n5
+gauss g1 l1 n0 8e-3 -1000 4e-3 -1200
+noxaxis
+maxtem 0 
+"""
+
+kat.parseCommands(cmds)
+
+plot_beam_trace(kat, 'n0', 'n17')
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pykat/node_network.py

@@ -9,6 +9,7 @@ from __future__ import division
 from __future__ import print_function
 from __future__ import unicode_literals
 
+import pykat
 from pykat import USE_GUI, NoGUIException
 
 if USE_GUI:
@@ -465,17 +466,17 @@ class NodeNetwork(object):
             
         if to_node == from_node:
             return []
-        
-        if from_node not in self.__nodes:
+    
+        if from_node.name not in self.__nodes:
             raise pkex.BasePyKatException("Node {0} cannot be found in this kat object".format(from_node))
 
-        if to_node not in self.__nodes:
+        if to_node.name not in self.__nodes:
             raise pkex.BasePyKatException("Node {0} cannot be found in this kat object".format(to_node))
         
         branches = []
         
-        fn = self.__nodes[from_node]
-        tn = self.__nodes[to_node]
+        fn = self.__nodes[from_node.name]
+        tn = self.__nodes[to_node.name]
         
         branches.append([False, False, fn, fn.components[1], []])
         branches.append([False, False, fn, fn.components[0], []])

pykat/tools/plotting/beamtrace.py

@@ -32,13 +32,11 @@ def plot_beam_trace(_kat, from_node, to_node):
     v = [c for c in zip(components, nodes) if isinstance(c[0], pykat.components.space)]
     spaces = [d[0] for d in v]
     nodes2  = [d[1] for d in v]
-
-    print [n.name for n in spaces   ]
-
+    
     pylab.figure()
     
     if len(spaces) > 0:
-        print "Plotting beam along spaces", ", ".join([s.name for s in spaces])
+        print("Plotting beam along spaces", ", ".join([s.name for s in spaces]))
     
         for d in kat.detectors.values():
             d.remove()
@@ -105,7 +103,7 @@ def plot_beam_trace(_kat, from_node, to_node):
         pylab.ylabel("Phase accumulation [deg]")
         pylab.xlabel("Distance [m]")
         pylab.xlim(min(L), max(L))
-        pylab.legend(['x','y'], 0)
+        pylab.legend(['x','y'], loc=0)
         pylab.tight_layout()
         pylab.show()
         
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