Add MT Visualization

nltk/align/api.py

@@ -11,6 +11,8 @@ from __future__ import print_function, unicode_literals
 
 from nltk.compat import python_2_unicode_compatible, string_types
 from nltk.metrics import precision, recall
+import subprocess
+
 
 @python_2_unicode_compatible
 class AlignedSent(object):
@@ -92,6 +94,56 @@ class AlignedSent(object):
 
         return "AlignedSent(%s, %s, %r)" % (words, mots, self._alignment)
 
+    def _to_dot(self):
+        """
+        Dot representation of the aligned sentence 
+        """ 
+        s = 'graph align {\n'
+        s += 'node[shape=plaintext]\n'
+        
+        # Declare node 
+        for w in self._words:
+            s += '"%s_source" [label="%s"] \n' % (w, w)
+            
+        for w in self._mots:
+            s += '"%s_target" [label="%s"] \n' % (w, w)
+            
+        # Alignment 
+        for u,v in self._alignment:           
+            s += '"%s_source" -- "%s_target" \n' % (self._words[u] , self._mots[v] )
+             
+        # Connect the source words 
+        for i in range(len(self._words)-1) :
+            s += '"%s_source" -- "%s_source" [style=invis]\n' % (self._words[i] , self._words[i+1])
+            
+        # Connect the target words 
+        for i in range(len(self._mots)-1) :
+            s += '"%s_target" -- "%s_target" [style=invis]\n' % (self._mots[i] , self._mots[i+1])
+            
+        # Put it in the same rank 
+        s  += '{rank = same; %s}\n' % (' '.join('"%s_source"' % w for w in self._words))
+        s  += '{rank = same; %s}\n' % (' '.join('"%s_target"' % w for w in self._mots))
+
+        s += '}'
+        
+        return s 
+        
+    def _repr_svg_(self):
+        """
+        Ipython magic : show SVG representation of this ``AlignedSent``. 
+        """
+        dot_string = self._to_dot().encode('utf8')
+        output_format = 'svg'
+        try:
+            process = subprocess.Popen(['dot', '-T%s' % output_format], stdin=subprocess.PIPE,
+                                       stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        except OSError:
+            raise Exception('Cannot find the dot binary from Graphviz package')
+        out, err = process.communicate(dot_string)
+         
+        return out
+    
+    
     def __str__(self):
         """
         Return a human-readable string representation for this ``AlignedSent``.