Merge pull request #2408 from ChienliMa/grad_for_round

theano/scalar/basic.py

@@ -2058,6 +2058,14 @@ class RoundHalfToEven(UnaryScalarOp):
     def impl(self, x):
         return numpy.round(x)
 
+    def grad(self, (x,), (gz,)):
+        rval = x.zeros_like()
+
+        if rval.type.dtype in discrete_types:
+            rval = rval.astype(theano.config.floatX)
+
+        return [rval]
+
     def c_code___(self, node, name, (x, ), (z, ), sub):
         typ = node.outputs[0].type.dtype
         if not typ in ['float32', 'float64']:
@@ -2140,9 +2148,16 @@ class RoundHalfAwayFromZero(UnaryScalarOp):
     See http://en.wikipedia.org/wiki/Rounding for more detail
     """
     def impl(self, x):
-
         return round_half_away_from_zero_vec(x)
 
+    def grad(self, (x,), (gz,)):
+        rval = x.zeros_like()
+
+        if rval.type.dtype in discrete_types:
+            rval = rval.astype(theano.config.floatX)
+
+        return [rval]
+
     def c_code(self, node, name, (x, ), (z, ), sub):
         if node.outputs[0].type.dtype in ['float32', 'float64']:
             return "%(z)s = round(%(x)s);" % locals()

theano/tensor/tests/test_basic.py

@@ -1099,6 +1099,10 @@ _grad_broadcast_unary_normal = dict(
         #empty = [numpy.asarray([])] # XXX: should this be included?
         )
 
+_grad_broadcast_unary_normal_no_complex_no_corner_case = copymod(
+        _grad_broadcast_unary_normal_no_complex,
+        without=['corner_case'])
+
 _grad_broadcast_unary_abs1_no_complex = dict(
         normal=[numpy.asarray(rand_ranged(-1, 1, (2, 3)), dtype=floatX)],
         )
@@ -1216,13 +1220,15 @@ TruncTester = makeBroadcastTester(
 
 RoundHalfToEvenTester = makeBroadcastTester(
     op=tensor.round_half_to_even,
-    expected=numpy.round,
-    good=_good_broadcast_unary_normal_float_no_complex)
-# TODO: Why complex are accepted in the next one?
+    expected= numpy.round,
+    good=_good_broadcast_unary_normal_float_no_complex,
+    grad=_grad_broadcast_unary_normal_no_complex_no_corner_case)
+
 RoundHalfToEvenInplaceTester = makeBroadcastTester(
     op=inplace.round_half_to_even_inplace,
-    expected=numpy.round,
-    good=_good_broadcast_unary_normal_float,
+    expected= numpy.round,
+    good=_good_broadcast_unary_normal_float_no_complex,
+    grad=_grad_broadcast_unary_normal_no_complex_no_corner_case,
     inplace=True)
 
 #numpy.vectorize don't handle correctly empty ndarray.
@@ -1230,19 +1236,23 @@ RoundHalfToEvenInplaceTester = makeBroadcastTester(
 #This happen in float32 mode.
 RoundHalfAwayFromZeroTester = makeBroadcastTester(
     op=tensor.round_half_away_from_zero,
-    expected=theano.scalar.basic.round_half_away_from_zero_vec,
-    good=_good_broadcast_unary_normal_float_no_empty_no_complex)
+    expected=lambda a:theano.scalar.basic.round_half_away_from_zero_vec(a),
+    good=_good_broadcast_unary_normal_float_no_empty_no_complex,
+    grad=_grad_broadcast_unary_normal_no_complex_no_corner_case)
     #_good_broadcast_unary_normal_float)
+
 RoundHalfAwayFromZeroInplaceTester = makeBroadcastTester(
     op=inplace.round_half_away_from_zero_inplace,
-    expected=theano.scalar.basic.round_half_away_from_zero_vec,
+    expected=lambda a:theano.scalar.basic.round_half_away_from_zero_vec(a),
     good=_good_broadcast_unary_normal_float_no_empty_no_complex,
+    grad=_grad_broadcast_unary_normal_no_complex_no_corner_case,
     inplace=True)
 
 SqrTester = makeBroadcastTester(op=tensor.sqr,
                                 expected=numpy.square,
                                 good=_good_broadcast_unary_normal,
                                 grad=_grad_broadcast_unary_normal)
+
 SqrInplaceTester = makeBroadcastTester(op=inplace.sqr_inplace,
                                        expected=numpy.square,
                                        good=_good_broadcast_unary_normal,