numpy-compatible mean

src/operator/numpy/np_broadcast_reduce_op.h

@@ -207,7 +207,6 @@ inline void NumpyReduceAxesBackwardUseNone(const nnvm::NodeAttrs& attrs,
     Stream<xpu> *s = ctx.get_stream<xpu>();
     MSHADOW_TYPE_SWITCH(outputs[0].type_flag_, IType, {
       Tensor<xpu, 1, IType> igrad = outputs[0].FlatTo1D<xpu, IType>(s);
-      printf("output size: %lu input_size: %lu\n", outputs[0].Size(), inputs[0].Size());
       igrad /= scalar<IType>(outputs[0].Size()/inputs[0].Size());
     });
   }

src/operator/numpy/np_broadcast_reduce_op_value.cc

@@ -75,5 +75,56 @@ NNVM_REGISTER_OP(_backward_numpy_sum)
 .set_num_inputs(1)
 .set_attr<FCompute>("FCompute<cpu>", NumpyReduceAxesBackwardUseNone<cpu>);
 
+inline bool IsIntType(const int dtype) {
+  return (dtype >= 3);
+}
+
+inline bool NumpyMeanType(const nnvm::NodeAttrs& attrs,
+                          std::vector<int> *in_attrs,
+                          std::vector<int> *out_attrs) {
+  CHECK_EQ(in_attrs->size(), 1U);
+  CHECK_EQ(out_attrs->size(), 1U);
+  const NumpyReduceAxesParam &param = nnvm::get<NumpyReduceAxesParam>(attrs.parsed);
+
+  if (param.dtype.has_value()) {
+    if (IsIntType(in_attrs->at(0)) && !IsIntType(param.dtype.value())) {
+      LOG(FATAL) << "Output cannot be float type when input is integer type for now";
+    }
+    TYPE_ASSIGN_CHECK(*out_attrs, 0, param.dtype.value());
+  } else {
+    TYPE_ASSIGN_CHECK(*out_attrs, 0, in_attrs->at(0));
+    TYPE_ASSIGN_CHECK(*in_attrs, 0, out_attrs->at(0));
+  }
+
+  return out_attrs->at(0) != -1 && in_attrs->at(0) != -1;
+}
+
+NNVM_REGISTER_OP(_numpy_mean)
+.describe(R"code()code" ADD_FILELINE)
+.set_num_inputs(1)
+.set_num_outputs(1)
+.set_attr_parser(ParamParser<NumpyReduceAxesParam>)
+.set_attr<mxnet::FInferShape>("FInferShape", NumpyReduceAxesShape)
+.set_attr<nnvm::FInferType>("FInferType", NumpyMeanType)
+.set_attr<nnvm::FListInputNames>("FListInputNames",
+  [](const NodeAttrs& attrs) {
+    return std::vector<std::string>{"a"};
+  })
+.add_argument("a", "NDArray-or-Symbol", "The input")
+.add_arguments(NumpyReduceAxesParam::__FIELDS__())
+.set_attr<FCompute>("FCompute<cpu>", NumpyReduceAxesCompute<cpu, mshadow_op::sum, true, true>)
+.set_attr<FResourceRequest>("FResourceRequest",
+  [](const NodeAttrs& attrs) {
+    return std::vector<ResourceRequest>{ResourceRequest::kTempSpace};
+  })
+.set_attr<nnvm::FGradient>("FGradient", ElemwiseGradUseNone{"_backward_numpy_mean"});
+
+NNVM_REGISTER_OP(_backward_numpy_mean)
+.set_num_outputs(1)
+.set_attr_parser(ParamParser<NumpyReduceAxesParam>)
+.set_attr<nnvm::TIsBackward>("TIsBackward", true)
+.set_num_inputs(1)
+.set_attr<FCompute>("FCompute<cpu>", NumpyReduceAxesBackwardUseNone<cpu, true>);
+
 }  // namespace op
 }  // namespace mxnet

src/operator/numpy/np_broadcast_reduce_op_value.cu

@@ -26,11 +26,19 @@
 
 namespace mxnet {
 namespace op {
+
 NNVM_REGISTER_OP(_numpy_sum)
 .set_attr<FCompute>("FCompute<gpu>", NumpyReduceAxesCompute<gpu, mshadow_op::sum, true>);
 
 NNVM_REGISTER_OP(_backward_numpy_sum)
 .set_attr<FCompute>("FCompute<gpu>", NumpyReduceAxesBackwardUseNone<gpu>);
 
+NNVM_REGISTER_OP(_numpy_mean)
+.set_attr<FCompute>("FCompute<gpu>", NumpyReduceAxesCompute<gpu, mshadow_op::sum, true, true>);
+
+NNVM_REGISTER_OP(_backward_numpy_mean)
+.set_attr<FCompute>("FCompute<gpu>", NumpyReduceAxesBackwardUseNone<gpu, true>);
+
+
 }  // namespace op
 }  // namespace mxnet

tests/python/unittest/test_numpy_op.py

@@ -31,7 +31,7 @@
 @with_seed()
 def test_np_sum():
     class TestSum(HybridBlock):
-        def __init__(self, axis=None, dtype=None, keepdims=False):# , initial=None):
+        def __init__(self, axis=None, dtype=None, keepdims=False):
             super(TestSum, self).__init__()
             self._axis = axis
             self._dtype = dtype
@@ -87,6 +87,68 @@ def is_int(dtype):
                         assert_almost_equal(mx_out.asnumpy(), np_out, rtol=1e-3, atol=1e-5)
 
 
+@mx.use_np_compat
+@with_seed()
+def test_np_mean():
+    class TestMean(HybridBlock):
+        def __init__(self, axis=None, dtype=None, keepdims=False):
+            super(TestMean, self).__init__()
+            self._axis = axis
+            self._dtype = dtype
+            self._keepdims = keepdims
+
+        def hybrid_forward(self, F, a, *args, **kwargs):
+            return F.numpy.mean(a, axis=self._axis, dtype=self._dtype, keepdims=self._keepdims)
+
+    def is_int(dtype):
+        return 'int' in dtype
+
+    in_data_dim = random.choice([2, 3, 4])
+    shape = rand_shape_nd(in_data_dim, dim=3)
+    acc_type = {'float16': 'float32', 'float32': 'float64', 'float64': 'float64',
+                'int8': 'int32', 'int32': 'int64', 'int64': 'int64'}
+    for hybridize in [False, True]:
+        for keepdims in [True, False]:
+            for axis in ([i for i in range(in_data_dim)] + [(), None]):
+                for itype in ['float16', 'float32', 'float64']:
+                    for dtype in ['float16', 'float32', 'float64']:
+                        print(itype, dtype)
+                        if is_int(dtype) and not is_int(itype):
+                            continue
+                        # test gluon
+                        test_mean = TestMean(axis=axis, dtype=dtype, keepdims=keepdims)
+                        if hybridize:
+                            test_mean.hybridize()
+                        if is_int(itype):
+                            x = _np.random.randint(-128, 128, shape, dtype=itype)
+                            x = mx.nd.array(x, dtype=itype)
+                        else:
+                            x = mx.nd.random.uniform(-1.0, 1.0, shape=shape, dtype=itype)
+                        x.attach_grad()
+                        expected_ret = _np.mean(x.asnumpy(), axis=axis, dtype=acc_type[itype], keepdims=keepdims)
+                        expected_ret = expected_ret.astype(dtype)
+                        with mx.autograd.record():
+                            y = test_mean(x)
+                        assert y.shape == expected_ret.shape
+                        assert_almost_equal(y.asnumpy(), expected_ret, rtol=1e-3 if dtype == 'float16' else 1e-3,
+                                            atol=1e-5 if dtype == 'float16' else 1e-5)
+
+                        y.backward()
+                        N = x.size / y.size
+                        assert same(x.grad.asnumpy(), _np.ones(shape=x.shape, dtype=x.dtype) / N)
+
+                        # test numeric
+                        if itype == 'float32' and dtype == 'float32':
+                            x_sym = mx.sym.Variable("x")
+                            mx_sym = mx.sym.numpy.mean(x_sym, axis=axis, dtype=dtype, keepdims=keepdims)
+                            check_numeric_gradient(mx_sym, [x], numeric_eps=1e-3, rtol=1e-3, atol=1e-4, dtype=_np.float32)
+
+                        # test imperative
+                        mx_out = np.mean(x, axis=axis, dtype=dtype, keepdims=keepdims)
+                        np_out = _np.mean(x.asnumpy(), axis=axis, dtype=acc_type[itype], keepdims=keepdims).astype(dtype)
+                        assert_almost_equal(mx_out.asnumpy(), np_out, rtol=1e-3, atol=1e-5)
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule()