[Cython] Translated an example showing how to make a reaction path diagram

interfaces/cython/cantera/examples/reaction_path.py

@@ -0,0 +1,46 @@
+"""
+Viewing a reaction path diagram.
+
+This script uses Graphviz to generate an image. You must have Graphviz installed
+and the program 'dot' must be on your path for this example to work.
+Graphviz can be obtained from http://www.graphviz.org/ or (possibly) installed
+using your operating system's package manager.
+"""
+
+import os
+import sys
+
+import cantera as ct
+
+# these lines can be replaced by any commands that generate
+# an object of a class derived from class Kinetics in some state.
+gas = ct.Solution('gri30.xml')
+gas.TPX = 1300.0, ct.one_atm, 'CH4:0.4, O2:1, N2:3.76'
+r = ct.Reactor(gas)
+net = ct.ReactorNet([r])
+T = r.T
+while T < 1900:
+    net.step(1.0)
+    T = r.T
+
+element = 'N'
+
+diagram = ct.ReactionPathDiagram(gas, element)
+diagram.title = 'Reaction path diagram following {0}'.format(element)
+diagram.label_threshold = 0.01
+
+dot_file = 'rxnpath.dot'
+img_file = 'rxnpath.png'
+img_path = os.path.join(os.getcwd(), img_file)
+
+diagram.write_dot(dot_file)
+print diagram.get_data()
+
+print("Wrote graphviz input file to '{0}'.".format(os.path.join(os.getcwd(), dot_file)))
+
+os.system('dot {0} -Tpng -o{1} -Gdpi=200'.format(dot_file, img_file))
+print("Wrote graphviz output file to '{0}'.".format(img_path))
+
+if "-view" in sys.argv:
+    import webbrowser
+    webbrowser.open('file:///' + img_path)