numpy operator hypot (#15901)

* rebase master

* edit test

* add IsIntType to check the input type

* fix error in test

* remove hypot in doc

python/mxnet/ndarray/numpy/_op.py

@@ -34,7 +34,7 @@
            'trunc', 'logical_not', 'arcsinh', 'arccosh', 'arctanh', 'tensordot',
            'linspace', 'expand_dims', 'tile', 'arange', 'split', 'concatenate', 'stack', 'vstack', 'mean',
            'maximum', 'minimum', 'swapaxes', 'clip', 'argmax', 'std', 'var', 'indices', 'copysign',
-           'ravel', 'hanning', 'hamming', 'blackman', 'flip', 'around']
+           'ravel', 'hanning', 'hamming', 'blackman', 'flip', 'around', 'hypot']
 
 
 @set_module('mxnet.ndarray.numpy')
@@ -3039,3 +3039,50 @@ def arctan2(x1, x2, out=None):
     """
     return _ufunc_helper(x1, x2, _npi.arctan2, _np.arctan2,
                          _npi.arctan2_scalar, _npi.rarctan2_scalar, out=out)
+
+
+@set_module('mxnet.ndarray.numpy')
+def hypot(x1, x2, out=None):
+    r"""
+    Given the "legs" of a right triangle, return its hypotenuse.
+
+    Equivalent to ``sqrt(x1**2 + x2**2)``, element-wise.  If `x1` or
+    `x2` is scalar_like (i.e., unambiguously cast-able to a scalar type),
+    it is broadcast for use with each element of the other argument.
+
+    Parameters
+    ----------
+    x1, x2 : array_like
+        Leg of the triangle(s).
+    out : ndarray, None, or tuple of ndarray and None, optional
+        A location into which the result is stored. If provided, it must have
+        a shape that the inputs broadcast to. If not provided or `None`,
+        a freshly-allocated array is returned. A tuple (possible only as a
+        keyword argument) must have length equal to the number of outputs.
+
+    Returns
+    -------
+    z : ndarray
+        The hypotenuse of the triangle(s).
+        This is a scalar if both `x1` and `x2` are scalars.
+
+    Notes
+    -----
+    This function differs from the original numpy.arange in the following aspects:
+	    - Only support float16, float32 and float64.
+
+    Examples
+    --------
+    >>> np.hypot(3*np.ones((3, 3)), 4*np.ones((3, 3)))
+    array([[ 5.,  5.,  5.],
+           [ 5.,  5.,  5.],
+           [ 5.,  5.,  5.]])
+
+    Example showing broadcast of scalar_like argument:
+
+    >>> np.hypot(3*np.ones((3, 3)), [4])
+    array([[ 5.,  5.,  5.],
+           [ 5.,  5.,  5.],
+           [ 5.,  5.,  5.]])
+    """
+    return _ufunc_helper(x1, x2, _npi.hypot, _np.hypot, _npi.hypot_scalar, None, out)

python/mxnet/numpy/multiarray.py

@@ -53,7 +53,7 @@
            'fix', 'ceil', 'floor', 'trunc', 'logical_not', 'arcsinh', 'arccosh', 'arctanh',
            'tensordot', 'linspace', 'expand_dims', 'tile', 'arange', 'split', 'concatenate',
            'stack', 'vstack', 'mean', 'maximum', 'minimum', 'swapaxes', 'clip', 'argmax', 'std', 'var', 'indices',
-           'copysign', 'ravel', 'hanning', 'hamming', 'blackman', 'flip', 'around', 'arctan2']
+           'copysign', 'ravel', 'hanning', 'hamming', 'blackman', 'flip', 'around', 'arctan2', 'hypot']
 
 # Return code for dispatching indexing function call
 _NDARRAY_UNSUPPORTED_INDEXING = -1
@@ -4566,3 +4566,52 @@ def arctan2(x1, x2, out=None):
     array([ 1.5707964, -1.5707964])
     """
     return _mx_nd_np.arctan2(x1, x2, out=out)
+
+
+@set_module('mxnet.numpy')
+def hypot(x1, x2, out=None):
+    r"""
+    hypot(x1, x2, out=None)
+
+    Given the "legs" of a right triangle, return its hypotenuse.
+
+    Equivalent to ``sqrt(x1**2 + x2**2)``, element-wise.  If `x1` or
+    `x2` is scalar_like (i.e., unambiguously cast-able to a scalar type),
+    it is broadcast for use with each element of the other argument.
+
+    Parameters
+    ----------
+    x1, x2 : array_like
+        Leg of the triangle(s).
+    out : ndarray, None, or tuple of ndarray and None, optional
+        A location into which the result is stored. If provided, it must have
+        a shape that the inputs broadcast to. If not provided or `None`,
+        a freshly-allocated array is returned. A tuple (possible only as a
+        keyword argument) must have length equal to the number of outputs.
+
+    Returns
+    -------
+    z : ndarray
+        The hypotenuse of the triangle(s).
+        This is a scalar if both `x1` and `x2` are scalars.
+
+    Notes
+    -----
+    This function differs from the original numpy.arange in the following aspects:
+	    - Only support float16, float32 and float64.
+
+    Examples
+    --------
+    >>> np.hypot(3*np.ones((3, 3)), 4*np.ones((3, 3)))
+    array([[ 5.,  5.,  5.],
+           [ 5.,  5.,  5.],
+           [ 5.,  5.,  5.]])
+
+    Example showing broadcast of scalar_like argument:
+
+    >>> np.hypot(3*np.ones((3, 3)), [4])
+    array([[ 5.,  5.,  5.],
+           [ 5.,  5.,  5.],
+           [ 5.,  5.,  5.]])
+    """
+    return _mx_nd_np.hypot(x1, x2, out=out)

python/mxnet/symbol/numpy/_symbol.py

@@ -36,7 +36,7 @@
            'trunc', 'logical_not', 'arcsinh', 'arccosh', 'arctanh', 'tensordot',
            'linspace', 'expand_dims', 'tile', 'arange', 'split', 'concatenate', 'stack', 'vstack', 'mean',
            'maximum', 'minimum', 'swapaxes', 'clip', 'argmax', 'std', 'var', 'indices', 'copysign',
-           'ravel', 'hanning', 'hamming', 'blackman', 'flip', 'around']
+           'ravel', 'hanning', 'hamming', 'blackman', 'flip', 'around', 'hypot']
 
 
 def _num_outputs(sym):
@@ -3240,4 +3240,37 @@ def arctan2(x1, x2, out=None):
                          _npi.arctan2_scalar, _npi.rarctan2_scalar, out=out)
 
 
+@set_module('mxnet.symbol.numpy')
+def hypot(x1, x2, out=None):
+    r"""
+    Given the "legs" of a right triangle, return its hypotenuse.
+
+    Equivalent to ``sqrt(x1**2 + x2**2)``, element-wise.  If `x1` or
+    `x2` is scalar_like (i.e., unambiguously cast-able to a scalar type),
+    it is broadcast for use with each element of the other argument.
+
+    Parameters
+    ----------
+    x1, x2 : array_like
+        Leg of the triangle(s).
+    out : ndarray, None, or tuple of ndarray and None, optional
+        A location into which the result is stored. If provided, it must have
+        a shape that the inputs broadcast to. If not provided or `None`,
+        a freshly-allocated array is returned. A tuple (possible only as a
+        keyword argument) must have length equal to the number of outputs.
+
+    Returns
+    -------
+    z : ndarray
+        The hypotenuse of the triangle(s).
+        This is a scalar if both `x1` and `x2` are scalars.
+
+    Notes
+    -----
+    This function differs from the original numpy.arange in the following aspects:
+        - Only support float16, float32 and float64.
+    """
+    return _ufunc_helper(x1, x2, _npi.hypot, _np.hypot, _npi.hypot_scalar, None, out)
+
+
 _set_np_symbol_class(_Symbol)

src/operator/numpy/np_elemwise_broadcast_op.cc

@@ -214,5 +214,54 @@ MXNET_OPERATOR_REGISTER_BINARY(_backward_npi_rarctan2_scalar)
 .set_attr<FCompute>("FCompute<cpu>",
                     BinaryScalarOp::Backward<cpu, mshadow_op::arctan2_rgrad>);
 
+bool HypotOpType(const nnvm::NodeAttrs& attrs,
+                 std::vector<int>* in_attrs,
+                 std::vector<int>* out_attrs) {
+  CHECK_EQ(in_attrs->size(), 2U);
+  CHECK_EQ(out_attrs->size(), 1U);
+
+  TYPE_ASSIGN_CHECK(*out_attrs, 0, in_attrs->at(0));
+  TYPE_ASSIGN_CHECK(*out_attrs, 0, in_attrs->at(1));
+  TYPE_ASSIGN_CHECK(*in_attrs, 0, out_attrs->at(0));
+  TYPE_ASSIGN_CHECK(*in_attrs, 1, out_attrs->at(0));
+
+  CHECK(IsFloatType(in_attrs->at(0))) << "Do not support `int` as input.\n";
+  return out_attrs->at(0) != -1;
+}
+
+// rigister hypot that do not support int here
+NNVM_REGISTER_OP(_npi_hypot)
+.set_num_inputs(2)
+.set_num_outputs(1)
+.set_attr<nnvm::FListInputNames>("FListInputNames",
+  [](const NodeAttrs& attrs) {
+    return std::vector<std::string>{"x1", "x2"};
+  })
+.set_attr<mxnet::FInferShape>("FInferShape", BinaryBroadcastShape)
+.set_attr<nnvm::FInferType>("FInferType", HypotOpType)
+.set_attr<FCompute>("FCompute<cpu>", BinaryBroadcastCompute<cpu, mshadow_op::hypot>)
+.set_attr<nnvm::FGradient>("FGradient", ElemwiseGradUseIn{"_backward_npi_hypot"})
+.set_attr<nnvm::FInplaceOption>("FInplaceOption",
+  [](const NodeAttrs& attrs) {
+    return std::vector<std::pair<int, int> >{{0, 0}, {1, 0}};
+  })
+.add_argument("x1", "NDArray-or-Symbol", "The input array")
+.add_argument("x2", "NDArray-or-Symbol", "The input array");
+
+NNVM_REGISTER_OP(_backward_npi_hypot)
+.set_num_inputs(3)
+.set_num_outputs(2)
+.set_attr<nnvm::TIsBackward>("TIsBackward", true)
+.set_attr<nnvm::FInplaceOption>("FInplaceOption",
+  [](const NodeAttrs& attrs) {
+    return std::vector<std::pair<int, int> > {{0, 1}};
+  })
+.set_attr<FResourceRequest>("FResourceRequest",
+  [](const NodeAttrs& attrs) {
+    return std::vector<ResourceRequest>{ResourceRequest::kTempSpace};
+  })
+.set_attr<FCompute>("FCompute<cpu>", BinaryBroadcastBackwardUseIn<cpu, mshadow_op::hypot_grad_left,
+                                                                  mshadow_op::hypot_grad_right>);
+
 }  // namespace op
 }  // namespace mxnet

src/operator/numpy/np_elemwise_broadcast_op.cu

@@ -55,6 +55,12 @@ NNVM_REGISTER_OP(_npi_arctan2)
 NNVM_REGISTER_OP(_backward_npi_arctan2)
 .set_attr<FCompute>("FCompute<gpu>", BinaryBroadcastBackwardUseIn<gpu, mshadow_op::arctan2_grad,
                                                                   mshadow_op::arctan2_rgrad>);
+NNVM_REGISTER_OP(_npi_hypot)
+.set_attr<FCompute>("FCompute<gpu>", BinaryBroadcastCompute<gpu, mshadow_op::hypot>);
+
+NNVM_REGISTER_OP(_backward_npi_hypot)
+.set_attr<FCompute>("FCompute<gpu>", BinaryBroadcastBackwardUseIn<gpu, mshadow_op::hypot_grad_left,
+                                                                  mshadow_op::hypot_grad_right>);
 
 NNVM_REGISTER_OP(_npi_add_scalar)
 .set_attr<FCompute>("FCompute<gpu>", BinaryScalarOp::Compute<gpu, op::mshadow_op::plus>);

src/operator/tensor/elemwise_binary_scalar_op_extended.cc

@@ -74,6 +74,7 @@ MXNET_OPERATOR_REGISTER_BINARY(_backward_rpower_scalar)
   cpu, mshadow_op::rpower_grad>);
 
 MXNET_OPERATOR_REGISTER_BINARY_SCALAR(_hypot_scalar)
+.add_alias("_npi_hypot_scalar")
 .set_attr<FCompute>("FCompute<cpu>", BinaryScalarOp::Compute<
   cpu, mshadow_op::hypot>)
 .set_attr<nnvm::FGradient>("FGradient", ElemwiseGradUseIn{ "_backward_hypot_scalar" })

tests/python/unittest/test_numpy_op.py

@@ -2479,6 +2479,72 @@ def hybrid_forward(self, F, x):
                 assert_almost_equal(mx_out.asnumpy(), np_out, rtol, atol)
 
 
+@with_seed()
+@use_np
+def test_np_hypot():
+    class TestHypot(HybridBlock):
+        def __init__(self):
+            super(TestHypot, self).__init__()
+
+        def hybrid_forward(self, F, x1, x2):
+            return F.np.hypot(x1, x2)
+
+    def dimReduce(src, des):
+        srcShape = src.shape
+        desShape = des.shape
+        if len(desShape) == 0:
+            return src.sum()
+        redu = []
+        for i, j in zip(range(len(srcShape)-1, -1, -1), range(len(desShape)-1, -1, -1)):
+            if srcShape[i] != desShape[j] and desShape[j] == 1:
+                redu.append(i)
+            if j == 0:
+                for k in range(0, i):
+                    redu.append(k)
+                break
+        if len(redu) > 0:
+            src = _np.reshape(src.sum(axis=tuple(redu)), desShape)
+        return src
+
+    types = ['float64', 'float32', 'float16']
+    for hybridize in [True, False]:
+        for shape1, shape2 in [[(3, 2), (3, 2)],  # tall matrices
+                               [(), ()],  # scalar only
+                               [(3, 0, 2), (3, 0, 2)],  # zero-dim
+                               [(3, 4, 5), (4, 1)],  # trailing dim broadcasting
+                               [(3, 4, 5), ()],  # scalar broadcasting
+                               [(), (1, 2, 3)],  # scalar broadcasting
+                               ]:
+            for oneType in types:
+                rtol = 1e-2 if oneType == 'float16' else 1e-3
+                atol = 1e-2 if oneType == 'float16' else 1e-5
+                test_hypot = TestHypot()
+                if hybridize:
+                    test_hypot.hybridize()
+                x1 = rand_ndarray(shape1, dtype=oneType).as_np_ndarray()
+                x2 = rand_ndarray(shape2, dtype=oneType).as_np_ndarray()
+                x11 = x1.asnumpy()
+                x21 = x2.asnumpy()
+                x1.attach_grad()
+                x2.attach_grad()
+                np_out = _np.hypot(x1.asnumpy(), x2.asnumpy())
+                with mx.autograd.record():
+                    mx_out = test_hypot(x1, x2)
+                assert mx_out.shape == np_out.shape
+                assert_almost_equal(mx_out.asnumpy(), np_out, rtol=rtol, atol=atol)
+                mx_out.backward()
+                np_backward_1 = x11 / np_out
+                np_backward_2 = x21 / np_out
+                np_backward_1 = dimReduce(np_backward_1, x11)
+                np_backward_2 = dimReduce(np_backward_2, x21)
+                assert_almost_equal(x1.grad.asnumpy(), np_backward_1, rtol=rtol, atol=atol)
+                assert_almost_equal(x2.grad.asnumpy(), np_backward_2, rtol=rtol, atol=atol)
+
+                mx_out = np.hypot(x1, x2)
+                np_out = _np.hypot(x1.asnumpy(), x2.asnumpy())
+                assert_almost_equal(mx_out.asnumpy(), np_out, rtol=rtol, atol=atol)
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule()