[PT FE] Support aten::softplus (openvinotoolkit#21367)

* [PT FE] Support aten::softplus

* Fix name

src/frontends/pytorch/src/op_table.cpp

@@ -498,6 +498,7 @@ const std::map<std::string, CreatorFunction> get_supported_ops_ts() {
         {"aten::size", op::translate_size},
         {"aten::slice", op::quantizable_op<op::translate_slice>},
         {"aten::softmax", op::translate_softmax},
+        {"aten::softplus", op::translate_1to1_match_1_inputs<opset10::SoftPlus>},
         {"aten::sort", op::translate_sort},
         {"aten::sqrt", op::translate_1to1_match_1_inputs_with_fp32_type_alignment<opset10::Sqrt>},
         {"aten::square", op::translate_square},

tests/layer_tests/pytorch_tests/test_softplus.py

@@ -0,0 +1,24 @@
+# Copyright (C) 2018-2023 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+import pytest
+import torch
+
+from pytorch_layer_test_class import PytorchLayerTest
+
+
+class aten_softplus(torch.nn.Module):
+    def forward(self, x):
+        return torch.nn.functional.softplus(x)
+
+
+class TestSoftplus(PytorchLayerTest):
+    def _prepare_input(self):
+        import numpy as np
+        return (np.random.randn(2, 4, 224, 224).astype(np.float32),)
+
+    @pytest.mark.nightly
+    @pytest.mark.precommit
+    def test_softplus(self, ie_device, precision, ir_version):
+        self._test(aten_softplus(), None, "aten::softplus",
+                   ie_device, precision, ir_version)