added largest function

theano/tensor/basic.py

@@ -997,6 +997,11 @@ def smallest(*args):
     """Return the [elementwise] smallest of a variable number of arguments (like python's min)."""
     return min(stack(*args), axis=0)
 
+@constructor
+def largest(*args):
+    """Return the [elementwise] largest of a variable number of arguments (like python's max)."""
+    return max(stack(*args), axis=0)
+
 
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 # Comparison