Roll nGraph Python API (#5237)

* Added Roll to nGraph Python API.

* Added empty line at the end of file.

* Corrected a typo.

* Added Roll test.

* Reformat code.

* Removed empty line.

ngraph/python/src/ngraph/__init__.py

@@ -135,6 +135,7 @@ from ngraph.opset7 import rnn_cell
 from ngraph.opset7 import rnn_sequence
 from ngraph.opset7 import roi_align
 from ngraph.opset7 import roi_pooling
+from ngraph.opset7 import roll
 from ngraph.opset7 import round
 from ngraph.opset7 import scatter_elements_update
 from ngraph.opset7 import scatter_update

ngraph/python/src/ngraph/opset7/__init__.py

@@ -120,6 +120,7 @@ from ngraph.opset3.ops import rnn_cell
 from ngraph.opset5.ops import rnn_sequence
 from ngraph.opset3.ops import roi_align
 from ngraph.opset2.ops import roi_pooling
+from ngraph.opset7.ops import roll
 from ngraph.opset5.ops import round
 from ngraph.opset3.ops import scatter_elements_update
 from ngraph.opset3.ops import scatter_update

ngraph/python/src/ngraph/opset7/ops.py

@@ -65,3 +65,21 @@ def gelu(
     }
 
     return _get_node_factory_opset7().create("Gelu", inputs, attributes)
+
+
+@nameable_op
+def roll(
+        data: NodeInput,
+        shift: NodeInput,
+        axes: NodeInput,
+) -> Node:
+    """Return a node which performs Roll operation.
+
+    @param data: The node with data tensor.
+    @param shift: The node with the tensor with numbers of places by which elements are shifted.
+    @param axes: The node with the tensor with axes along which elements are shifted.
+    @return The new node performing a Roll operation on the input tensor.
+    """
+    inputs = as_nodes(data, shift, axes)
+
+    return _get_node_factory_opset7().create("Roll", inputs)

ngraph/python/tests/__init__.py

@@ -163,3 +163,5 @@ xfail_issue_49753 = xfail_test(reason="RuntimeError: Unsupported dynamic ops: v1
 xfail_issue_49754 = xfail_test(reason="RuntimeError: Unsupported dynamic ops: v1::TopKIE")
 xfail_issue_52463 = xfail_test(reason="test_operator_add_size1_singleton_broadcast_cpu - "
                                       "Not equal to tolerance")
+
+xfail_issue_49391 = xfail_test(reason="Roll is not implemented in CPU plugin.")

ngraph/python/tests/test_ngraph/test_roll.py

@@ -0,0 +1,20 @@
+import ngraph as ng
+import numpy as np
+from tests import xfail_issue_49391
+from tests.runtime import get_runtime
+
+
+@xfail_issue_49391
+def test_roll():
+    runtime = get_runtime()
+    input = np.reshape(np.arange(10), (2, 5))
+    input_tensor = ng.constant(input)
+    input_shift = ng.constant(np.array([-10, 7], dtype=np.int32))
+    input_axes = ng.constant(np.array([-1, 0], dtype=np.int32))
+
+    roll_node = ng.roll(input_tensor, input_shift, input_axes)
+    computation = runtime.computation(roll_node)
+    roll_results = computation()
+    expected_results = np.roll(input, shift=(-10, 7), axis=(-1, 0))
+
+    assert np.allclose(roll_results, expected_results)