Fix exceptions in scalar.

theano/scalar/basic.py

@@ -39,7 +39,7 @@ builtin_int = int
 builtin_float = float
 
 
-class ComplexError(Exception):
+class ComplexError(NotImplementedError):
     """
     Raised if complex numbers are used in an unsupported operation.
 
@@ -2197,7 +2197,7 @@ class Sgn(UnaryScalarOp):
             return '%(z)s = (%(x)s > 0) ? 1. : ((%(x)s < 0) ? -1. : (isnan(%(x)s) ? NAN : 0.));' % locals()
         if type in int_types:
             return "%(z)s = (%(x)s >= 0) ? (%(x)s == 0) ? 0 : 1 : -1;" % locals()
-        raise TypeError()  # complex has no sgn
+        raise ComplexError('complex has no sgn')
 
     def c_code_cache_version(self):
         s = super(Sgn, self).c_code_cache_version()
@@ -2299,8 +2299,8 @@ class RoundHalfToEven(UnaryScalarOp):
         (x,) = inputs
         (z,) = outputs
         typ = node.outputs[0].type.dtype
-        if typ not in ['float32', 'float64']:
-            Exception("The output should be float32 or float64")
+        if not typ.startswith('float'):
+            raise NotImplementedError("The output should a float")
 
         return dedent("""
             #ifndef ROUNDING_EPSILON
@@ -2398,7 +2398,7 @@ class RoundHalfAwayFromZero(UnaryScalarOp):
         if node.outputs[0].type.dtype in ['float32', 'float64']:
             return "%(z)s = round(%(x)s);" % locals()
         else:
-            Exception("The output should be float32 or float64")
+            raise NotImplementedError("The output should be a float")
 round_half_away_from_zero = RoundHalfAwayFromZero(same_out_float_only)