Added new option 'implicit' to input parameters that cannot be provided by the user

theano/compile/io.py

@@ -27,9 +27,13 @@ class SymbolicInput(object):
 
     autoname: Bool (default: True)
         See the name option.
+
+    implicit: Bool (default: False)
+        See help(In).
     """
 
-    def __init__(self, variable, name=None, update=None, mutable=None, strict=False, autoname=True):
+    def __init__(self, variable, name=None, update=None, mutable=None, strict=False, autoname=True,
+            implicit=False):
         self.variable = variable
         self.name = variable.name if (autoname and name is None) else name
         if self.name is not None and not isinstance(self.name, str):
@@ -37,6 +41,7 @@ class SymbolicInput(object):
         self.update = update
         self.mutable = mutable if (mutable is not None) else (update is not None)
         self.strict = strict
+        self.implicit = implicit
 
     def __str__(self):
         if self.update:
@@ -136,10 +141,21 @@ class In(SymbolicInput):
 
     autoname: Bool (default: True)
         See the name option.
+
+    implicit: Bool (default: False)
+        True: This input is implicit in the sense that the user is not allowed
+            to provide a value for it. Requires 'value' to be set.
+        False: The user can provide a value for this input.
+
     """
-    def __init__(self, variable, name=None, value=None, update=None, mutable=None, strict=False, autoname=True):
-        super(In, self).__init__(variable, name, update, mutable, strict, autoname)
+    def __init__(self, variable, name=None, value=None, update=None,
+            mutable=None, strict=False, autoname=True,
+            implicit=False):
+        super(In, self).__init__(variable, name, update, mutable, strict,
+                autoname, implicit = implicit)
         self.value = value
+        if implicit and value is None:
+            raise TypeError('An implicit input must be given a default value')
 
 
 class SymbolicOutput(object):