Specify LogSoftmax-5 operation (#2382)

* Specify LogSoftmax operation

* Fix feedback

docs/doxygen/ie_docs.xml

@@ -174,6 +174,7 @@
                         <tab type="user" title="LogicalNot-1" url="@ref openvino_docs_ops_logical_LogicalNot_1"/>
                         <tab type="user" title="LogicalOr-1" url="@ref openvino_docs_ops_logical_LogicalOr_1"/>
                         <tab type="user" title="LogicalXor-1" url="@ref openvino_docs_ops_logical_LogicalXor_1"/>
+                        <tab type="user" title="LogSoftmax-5" url="@ref openvino_docs_ops_activation_LogSoftmax_5"/>
                         <tab type="user" title="MVN-1" url="@ref openvino_docs_ops_normalization_MVN_1"/>
                         <tab type="user" title="MatMul-1" url="@ref openvino_docs_ops_matrix_MatMul_1"/>
                         <tab type="user" title="MaxPool-1" url="@ref openvino_docs_ops_pooling_MaxPool_1"/>

docs/ops/activation/LogSoftmax_5.md

@@ -0,0 +1,62 @@
+## LogSoftMax <a name="LogSoftmax"></a> {#openvino_docs_ops_activation_LogSoftmax_5}
+
+**Versioned name**: *LogSoftmax-5*
+
+**Category**: *Activation*
+
+**Short description**: LogSoftmax computes the natural logarithm of softmax values for the given input.
+
+**Note**:  This is recommended to not compute LogSoftmax directly as Log(Softmax(x, axis)), more numeric stable is to compute LogSoftmax as:
+\f[
+t = (x - ReduceMax(x, axis)) \\
+LogSoftmax(x, axis) = t - Log(ReduceSum(Exp(t), axis))
+\f]
+
+**Attributes**
+
+* *axis*
+
+  * **Description**: *axis* represents the axis of which the *LogSoftmax* is calculated. Negative value means counting dimensions from the back.
+  * **Range of values**: any integer value
+  * **Type**: int
+  * **Default value**: 1
+  * **Required**: *no*
+
+**Inputs**:
+
+*   **1**: Input tensor *x* of type T with enough number of dimension to be compatible with *axis* attribute. Required.
+
+**Outputs**:
+
+*   **1**: The resulting tensor of the same shape and of type T.
+
+**Types**
+
+* *T*: any floating point type.
+
+**Mathematical Formulation**
+
+\f[
+y_{c} = ln\left(\frac{e^{Z_{c}}}{\sum_{d=1}^{C}e^{Z_{d}}}\right)
+\f]
+where \f$C\f$ is a size of tensor along *axis* dimension.
+
+**Example**
+
+```xml
+<layer ... type="LogSoftmax" ... >
+    <data axis="1" />
+    <input>
+        <port id="0">
+            <dim>256</dim>
+            <dim>56</dim>
+        </port>
+    </input>
+    <output>
+        <port id="3">
+            <dim>256</dim>
+            <dim>56</dim>
+        </port>
+    </output>
+</layer>
+```

docs/ops/opset5.md

@@ -75,6 +75,7 @@ declared in `namespace opset5`.
 * [LogicalNot](logical/LogicalNot_1.md)
 * [LogicalOr](logical/LogicalOr_1.md)
 * [LogicalXor](logical/LogicalXor_1.md)
+* [LogSoftmax](activation/LogSoftmax_5.md)
 * [LRN](normalization/LRN_1.md)
 * [LSTMCell](sequence/LSTMCell_1.md)
 * [LSTMSequence](sequence/LSTMSequence_1.md)