[Py] Python wrappers for nGraph operations (#719)

* Add test for ng.absolute

- remove unnecesary repetitive call to as_node

* Add Acos operation with UT.

- update docsrings
- refactor and parameterize unit tests

* Review refactoring fix.

* Review refactoring fix part 2.

* Add Asin and Atan nGraph operation wrappers.

python/ngraph/__init__.py

@@ -17,7 +17,10 @@
 
 from ngraph.ops import absolute
 from ngraph.ops import absolute as abs
+from ngraph.ops import acos
 from ngraph.ops import add
+from ngraph.ops import asin
+from ngraph.ops import atan
 from ngraph.ops import avg_pool
 from ngraph.ops import broadcast
 from ngraph.ops import ceiling

python/ngraph/ops.py

@@ -20,19 +20,19 @@ import numpy as np
 from ngraph.impl import AxisSet, AxisVector, Coordinate, CoordinateDiff, Node, NodeVector, \
     Shape, Strides
 
-from ngraph.impl.op import Abs, Add, AvgPool, Broadcast, Ceiling, Concat, Constant, Convert, \
-    Convolution, Divide, Dot, Equal, Exp, Floor, Greater, GreaterEq, Less, LessEq, Log, Max, \
-    Maximum, MaxPool, Min, Minimum, Multiply, Negative, Not, NotEqual, Parameter, Product, \
-    Reshape, Slice, Sqrt, Subtract, Sum, Tanh
+from ngraph.impl.op import Abs, Acos, Add, Asin, Atan, AvgPool, Broadcast, Ceiling, Concat, \
+    Constant, Convert, Convolution, Divide, Dot, Equal, Exp, Floor, Greater, GreaterEq, Less, \
+    LessEq, Log, Max, Maximum, MaxPool, Min, Minimum, Multiply, Negative, Not, NotEqual, Parameter,\
+    Product, Reshape, Slice, Sqrt, Subtract, Sum, Tanh
 
-from typing import Iterable, List, Optional
+from typing import Iterable, List
 
 from ngraph.utils.broadcasting import get_broadcast_axes
 from ngraph.utils.decorators import nameable_op, binary_op, unary_op
 from ngraph.utils.input_validation import assert_list_of_ints
 from ngraph.utils.reduction import get_reduction_axes
 from ngraph.utils.types import NumericType, NumericData, TensorShape, make_constant_node, \
-    as_node, NodeInput
+    NodeInput
 from ngraph.utils.types import get_element_type
 
 
@@ -54,11 +54,48 @@ def constant(value, dtype=None, name=None):  # type: (NumericData, NumericType,
 # Unary ops
 @unary_op
 def absolute(node, name=None):  # type: (NodeInput, str) -> Node
-    """Return node which applies f(x) = abs(x) to the input node elementwise."""
-    node = as_node(node)
+    """Return node which applies f(x) = abs(x) to the input node element-wise.
+
+    :param node: One of: input node, array or scalar.
+    :param name: Optional new name for output node.
+    :return: New node with Abs operation applied on it.
+    """
     return Abs(node)
 
 
+@unary_op
+def acos(node, name=None):  # type: (NodeInput, str) -> Node
+    """Apply inverse cosine function on the input node element-wise.
+
+    :param node: One of: input node, array or scalar.
+    :param name: Optional new name for output node.
+    :return: New node with arccos operation applied on it.
+    """
+    return Acos(node)
+
+
+@unary_op
+def asin(node, name=None):  # type: (NodeInput, str) -> Node
+    """Apply inverse sine function on the input node element-wise.
+
+    :param node: One of: input node, array or scalar.
+    :param name: Optional new name for output node.
+    :return: New node with arcsin operation applied on it.
+    """
+    return Asin(node)
+
+
+@unary_op
+def atan(node, name=None):  # type: (NodeInput, str) -> Node
+    """Apply inverse tangent function on the input node element-wise.
+
+    :param node: One of: input node, array or scalar.
+    :param name: Optional new name for output node.
+    :return: New node with arctan operation applied on it.
+    """
+    return Atan(node)
+
+
 @unary_op
 def sqrt(node, name=None):  # type: (NodeInput, str) -> Node
     """Return node which applies square root to the input node elementwise."""
@@ -128,7 +165,7 @@ def subtract(left_node, right_node, name=None):  # type: (NodeInput, NodeInput,
 
 @binary_op
 def add(left_node, right_node, name=None):  # type: (NodeInput, NodeInput, str) -> Node
-    """Return node which applies f(x) = A+B to the input nodes elementwise."""
+    """Return node which applies f(x) = A+B to the input nodes element-wise."""
     return Add(left_node, right_node)
 
 

python/test/ngraph/test_ops_unary.py

+# ******************************************************************************
+# Copyright 2018 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ******************************************************************************
+import numpy as np
+import pytest
+
+import ngraph as ng
+
+
+def _get_runtime():
+    manager_name = pytest.config.getoption('backend', default='CPU')
+    return ng.runtime(manager_name=manager_name)
+
+
+def _run_unary_op_node(input_data, unary_op):
+    runtime = _get_runtime()
+    parameter_a = ng.parameter(input_data.shape, name='A', dtype=np.float32)
+    node = unary_op(parameter_a)
+    computation = runtime.computation(node, parameter_a)
+    return computation(input_data)
+
+
+def _run_unary_op_numeric_data(input_data, unary_op):
+    runtime = _get_runtime()
+    node = unary_op(input_data)
+    computation = runtime.computation(node)
+    return computation()
+
+
+@pytest.mark.parametrize('ng_api_fn, numpy_fn, input_data', [
+    (ng.absolute, np.abs, -1 + np.random.rand(2, 3, 4) * 2),
+    (ng.absolute, np.abs, np.float32(-3)),
+    (ng.acos, np.arccos, -1 + np.random.rand(2, 3, 4) * 2),
+    (ng.acos, np.arccos, np.float32(-0.5)),
+    (ng.asin, np.arcsin, -1 + np.random.rand(2, 3, 4) * 2),
+    (ng.asin, np.arcsin, np.float32(-0.5)),
+    (ng.atan, np.arctan, -100 + np.random.rand(2, 3, 4) * 200),
+    (ng.atan, np.arctan, np.float32(-0.5)),
+])
+def test_unary_op(ng_api_fn, numpy_fn, input_data):
+    expected = numpy_fn(input_data)
+
+    result = _run_unary_op_node(input_data, ng_api_fn)
+    assert np.allclose(result, expected)
+
+    result = _run_unary_op_numeric_data(input_data, ng_api_fn)
+    assert np.allclose(result, expected)