COMPMID-1008: Fix Doxygen issues

Change-Id: Ie73d8771f85d1f5b059f3a56f1bbd73c98e94a38
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/124723
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Tested-by: Jenkins <bsgcomp@arm.com>
diff --git a/utils/TypePrinter.h b/utils/TypePrinter.h
index 1734715..f0c1bd1 100644
--- a/utils/TypePrinter.h
+++ b/utils/TypePrinter.h
@@ -41,7 +41,13 @@
 
 namespace arm_compute
 {
-/** Formatted output of the Dimensions type. */
+/** Formatted output of the Dimensions type.
+ *
+ * @param[out] os         Output stream.
+ * @param[in]  dimensions Type to output.
+ *
+ * @return Modified output stream.
+ */
 template <typename T>
 inline ::std::ostream &operator<<(::std::ostream &os, const Dimensions<T> &dimensions)
 {
@@ -58,7 +64,13 @@
     return os;
 }
 
-/** Formatted output of the NonLinearFilterFunction type. */
+/** Formatted output of the NonLinearFilterFunction type.
+ *
+ * @param[out] os       Output stream.
+ * @param[in]  function Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const NonLinearFilterFunction &function)
 {
     switch(function)
@@ -79,6 +91,12 @@
     return os;
 }
 
+/** Formatted output of the NonLinearFilterFunction type.
+ *
+ * @param[in] function Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const NonLinearFilterFunction &function)
 {
     std::stringstream str;
@@ -86,7 +104,13 @@
     return str.str();
 }
 
-/** Formatted output of the MatrixPattern type. */
+/** Formatted output of the MatrixPattern type.
+ *
+ * @param[out] os      Output stream.
+ * @param[in]  pattern Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const MatrixPattern &pattern)
 {
     switch(pattern)
@@ -110,6 +134,12 @@
     return os;
 }
 
+/** Formatted output of the MatrixPattern type.
+ *
+ * @param[in] pattern Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const MatrixPattern &pattern)
 {
     std::stringstream str;
@@ -117,7 +147,13 @@
     return str.str();
 }
 
-/** Formatted output of the RoundingPolicy type. */
+/** Formatted output of the RoundingPolicy type.
+ *
+ * @param[out] os              Output stream.
+ * @param[in]  rounding_policy Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const RoundingPolicy &rounding_policy)
 {
     switch(rounding_policy)
@@ -138,7 +174,13 @@
     return os;
 }
 
-/** Formatted output of the WeightsInfo type. */
+/** Formatted output of the WeightsInfo type.
+ *
+ * @param[out] os           Output stream.
+ * @param[in]  weights_info Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const WeightsInfo &weights_info)
 {
     os << weights_info.are_reshaped() << ";";
@@ -147,14 +189,26 @@
     return os;
 }
 
-/** Formatted output of the ROIPoolingInfo type. */
+/** Formatted output of the ROIPoolingInfo type.
+ *
+ * @param[out] os        Output stream.
+ * @param[in]  pool_info Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const ROIPoolingLayerInfo &pool_info)
 {
     os << pool_info.pooled_width() << "x" << pool_info.pooled_height() << "~" << pool_info.spatial_scale();
     return os;
 }
 
-/** Formatted output of the QuantizationInfo type. */
+/** Formatted output of the QuantizationInfo type.
+ *
+ * @param[out] os                Output stream.
+ * @param[in]  quantization_info Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const QuantizationInfo &quantization_info)
 {
     os << "Scale:" << quantization_info.scale << "~"
@@ -162,6 +216,12 @@
     return os;
 }
 
+/** Formatted output of the QuantizationInfo type.
+ *
+ * @param[in] quantization_info Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const QuantizationInfo &quantization_info)
 {
     std::stringstream str;
@@ -169,6 +229,13 @@
     return str.str();
 }
 
+/** Formatted output of the FixedPointOp type.
+ *
+ * @param[out] os Output stream.
+ * @param[in]  op Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const FixedPointOp &op)
 {
     switch(op)
@@ -201,6 +268,12 @@
     return os;
 }
 
+/** Formatted output of the FixedPointOp type.
+ *
+ * @param[in] op Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const FixedPointOp &op)
 {
     std::stringstream str;
@@ -208,7 +281,13 @@
     return str.str();
 }
 
-/** Formatted output of the activation function type. */
+/** Formatted output of the activation function type.
+ *
+ * @param[out] os           Output stream.
+ * @param[in]  act_function Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const ActivationLayerInfo::ActivationFunction &act_function)
 {
     switch(act_function)
@@ -253,6 +332,12 @@
     return os;
 }
 
+/** Formatted output of the activation function info type.
+ *
+ * @param[in] info Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const arm_compute::ActivationLayerInfo &info)
 {
     std::stringstream str;
@@ -260,6 +345,12 @@
     return str.str();
 }
 
+/** Formatted output of the activation function type.
+ *
+ * @param[in] function Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const arm_compute::ActivationLayerInfo::ActivationFunction &function)
 {
     std::stringstream str;
@@ -267,7 +358,13 @@
     return str.str();
 }
 
-/** Formatted output of the NormType type. */
+/** Formatted output of the NormType type.
+ *
+ * @param[out] os        Output stream.
+ * @param[in]  norm_type Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const NormType &norm_type)
 {
     switch(norm_type)
@@ -288,6 +385,12 @@
     return os;
 }
 
+/** Formatted output of @ref NormalizationLayerInfo.
+ *
+ * @param[in] info Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const arm_compute::NormalizationLayerInfo &info)
 {
     std::stringstream str;
@@ -295,14 +398,26 @@
     return str.str();
 }
 
-/** Formatted output of @ref NormalizationLayerInfo. */
+/** Formatted output of @ref NormalizationLayerInfo.
+ *
+ * @param[out] os   Output stream.
+ * @param[in]  info Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const NormalizationLayerInfo &info)
 {
     os << info.type() << ":NormSize=" << info.norm_size();
     return os;
 }
 
-/** Formatted output of the PoolingType type. */
+/** Formatted output of the PoolingType type.
+ *
+ * @param[out] os        Output stream.
+ * @param[in]  pool_type Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const PoolingType &pool_type)
 {
     switch(pool_type)
@@ -323,7 +438,13 @@
     return os;
 }
 
-/** Formatted output of @ref PoolingLayerInfo. */
+/** Formatted output of @ref PoolingLayerInfo.
+ *
+ * @param[out] os   Output stream.
+ * @param[in]  info Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const PoolingLayerInfo &info)
 {
     os << info.pool_type();
@@ -331,6 +452,12 @@
     return os;
 }
 
+/** Formatted output of @ref RoundingPolicy.
+ *
+ * @param[in] rounding_policy Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const RoundingPolicy &rounding_policy)
 {
     std::stringstream str;
@@ -338,7 +465,13 @@
     return str.str();
 }
 
-/** Formatted output of the DataLayout type. */
+/** Formatted output of the DataLayout type.
+ *
+ * @param[out] os          Output stream.
+ * @param[in]  data_layout Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const DataLayout &data_layout)
 {
     switch(data_layout)
@@ -359,6 +492,12 @@
     return os;
 }
 
+/** Formatted output of the DataLayout type.
+ *
+ * @param[in] data_layout Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const arm_compute::DataLayout &data_layout)
 {
     std::stringstream str;
@@ -366,7 +505,13 @@
     return str.str();
 }
 
-/** Formatted output of the DataType type. */
+/** Formatted output of the DataType type.
+ *
+ * @param[out] os        Output stream.
+ * @param[in]  data_type Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const DataType &data_type)
 {
     switch(data_type)
@@ -426,6 +571,12 @@
     return os;
 }
 
+/** Formatted output of the DataType type.
+ *
+ * @param[in] data_type Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const arm_compute::DataType &data_type)
 {
     std::stringstream str;
@@ -433,7 +584,13 @@
     return str.str();
 }
 
-/** Formatted output of the Format type. */
+/** Formatted output of the Format type.
+ *
+ * @param[out] os     Output stream.
+ * @param[in]  format Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const Format &format)
 {
     switch(format)
@@ -496,6 +653,12 @@
     return os;
 }
 
+/** Formatted output of the Format type.
+ *
+ * @param[in] format Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const Format &format)
 {
     std::stringstream str;
@@ -503,7 +666,13 @@
     return str.str();
 }
 
-/** Formatted output of the Channel type. */
+/** Formatted output of the Channel type.
+ *
+ * @param[out] os      Output stream.
+ * @param[in]  channel Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const Channel &channel)
 {
     switch(channel)
@@ -551,6 +720,12 @@
     return os;
 }
 
+/** Formatted output of the Channel type.
+ *
+ * @param[in] channel Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const Channel &channel)
 {
     std::stringstream str;
@@ -558,7 +733,13 @@
     return str.str();
 }
 
-/** Formatted output of the BorderMode type. */
+/** Formatted output of the BorderMode type.
+ *
+ * @param[out] os   Output stream.
+ * @param[in]  mode Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const BorderMode &mode)
 {
     switch(mode)
@@ -579,7 +760,13 @@
     return os;
 }
 
-/** Formatted output of the BorderSize type. */
+/** Formatted output of the BorderSize type.
+ *
+ * @param[out] os     Output stream.
+ * @param[in]  border Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const BorderSize &border)
 {
     os << border.top << ","
@@ -590,7 +777,13 @@
     return os;
 }
 
-/** Formatted output of the InterpolationPolicy type. */
+/** Formatted output of the InterpolationPolicy type.
+ *
+ * @param[out] os     Output stream.
+ * @param[in]  policy Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const InterpolationPolicy &policy)
 {
     switch(policy)
@@ -611,7 +804,13 @@
     return os;
 }
 
-/** Formatted output of the SamplingPolicy type. */
+/** Formatted output of the SamplingPolicy type.
+ *
+ * @param[out] os     Output stream.
+ * @param[in]  policy Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const SamplingPolicy &policy)
 {
     switch(policy)
@@ -629,7 +828,12 @@
     return os;
 }
 
-/** Formatted output of the TensorInfo type. */
+/** Formatted output of the TensorInfo type.
+ *
+ * @param[in] info Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const TensorInfo &info)
 {
     std::stringstream str;
@@ -641,6 +845,12 @@
 }
 
 //FIXME: Check why this doesn't work and the TensorShape and Coordinates overload are needed
+/** Formatted output of the Dimensions type.
+ *
+ * @param[in] dimensions Type to output.
+ *
+ * @return Formatted string.
+ */
 template <typename T>
 inline std::string to_string(const Dimensions<T> &dimensions)
 {
@@ -649,6 +859,12 @@
     return str.str();
 }
 
+/** Formatted output of the Strides type.
+ *
+ * @param[in] stride Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const Strides &stride)
 {
     std::stringstream str;
@@ -656,7 +872,12 @@
     return str.str();
 }
 
-/** Formatted output of the TensorShape type. */
+/** Formatted output of the TensorShape type.
+ *
+ * @param[in] shape Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const TensorShape &shape)
 {
     std::stringstream str;
@@ -664,7 +885,12 @@
     return str.str();
 }
 
-/** Formatted output of the Coordinates type. */
+/** Formatted output of the Coordinates type.
+ *
+ * @param[in] coord Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const Coordinates &coord)
 {
     std::stringstream str;
@@ -672,7 +898,13 @@
     return str.str();
 }
 
-/** Formatted output of the Rectangle type. */
+/** Formatted output of the Rectangle type.
+ *
+ * @param[out] os   Output stream.
+ * @param[in]  rect Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const Rectangle &rect)
 {
     os << rect.width << "x" << rect.height;
@@ -681,7 +913,13 @@
     return os;
 }
 
-/** Formatted output of the PadStridInfo type. */
+/** Formatted output of the PadStrideInfo type.
+ *
+ * @param[out] os              Output stream.
+ * @param[in]  pad_stride_info Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const PadStrideInfo &pad_stride_info)
 {
     os << pad_stride_info.stride().first << "," << pad_stride_info.stride().second;
@@ -692,6 +930,12 @@
     return os;
 }
 
+/** Formatted output of the PadStrideInfo type.
+ *
+ * @param[in] pad_stride_info Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const PadStrideInfo &pad_stride_info)
 {
     std::stringstream str;
@@ -699,6 +943,12 @@
     return str.str();
 }
 
+/** Formatted output of the BorderMode type.
+ *
+ * @param[in] mode Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const BorderMode &mode)
 {
     std::stringstream str;
@@ -706,6 +956,12 @@
     return str.str();
 }
 
+/** Formatted output of the BorderSize type.
+ *
+ * @param[in] border Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const BorderSize &border)
 {
     std::stringstream str;
@@ -713,6 +969,12 @@
     return str.str();
 }
 
+/** Formatted output of the InterpolationPolicy type.
+ *
+ * @param[in] policy Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const InterpolationPolicy &policy)
 {
     std::stringstream str;
@@ -720,6 +982,12 @@
     return str.str();
 }
 
+/** Formatted output of the SamplingPolicy type.
+ *
+ * @param[in] policy Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const SamplingPolicy &policy)
 {
     std::stringstream str;
@@ -727,7 +995,13 @@
     return str.str();
 }
 
-/** Formatted output of the ConversionPolicy type. */
+/** Formatted output of the ConvertPolicy type.
+ *
+ * @param[out] os     Output stream.
+ * @param[in]  policy Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const ConvertPolicy &policy)
 {
     switch(policy)
@@ -752,7 +1026,13 @@
     return str.str();
 }
 
-/** Formatted output of the Reduction Operations. */
+/** Formatted output of the Reduction Operations.
+ *
+ * @param[out] os Output stream.
+ * @param[in]  op Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const ReductionOperation &op)
 {
     switch(op)
@@ -767,6 +1047,12 @@
     return os;
 }
 
+/** Formatted output of the Reduction Operations.
+ *
+ * @param[in] op Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const ReductionOperation &op)
 {
     std::stringstream str;
@@ -774,6 +1060,12 @@
     return str.str();
 }
 
+/** Formatted output of the Norm Type.
+ *
+ * @param[in] type Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const NormType &type)
 {
     std::stringstream str;
@@ -781,6 +1073,12 @@
     return str.str();
 }
 
+/** Formatted output of the Pooling Type.
+ *
+ * @param[in] type Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const PoolingType &type)
 {
     std::stringstream str;
@@ -788,6 +1086,12 @@
     return str.str();
 }
 
+/** Formatted output of the Pooling Layer Info.
+ *
+ * @param[in] info Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const PoolingLayerInfo &info)
 {
     std::stringstream str;
@@ -803,7 +1107,13 @@
     return str.str();
 }
 
-/** Formatted output of the KeyPoint type. */
+/** Formatted output of the KeyPoint type.
+ *
+ * @param[out] os    Output stream
+ * @param[in]  point Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const KeyPoint &point)
 {
     os << "{x=" << point.x << ","
@@ -817,7 +1127,13 @@
     return os;
 }
 
-/** Formatted output of the PhaseType type. */
+/** Formatted output of the PhaseType type.
+ *
+ * @param[out] os         Output stream
+ * @param[in]  phase_type Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const PhaseType &phase_type)
 {
     switch(phase_type)
@@ -835,6 +1151,12 @@
     return os;
 }
 
+/** Formatted output of the PhaseType type.
+ *
+ * @param[in] type Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const arm_compute::PhaseType &type)
 {
     std::stringstream str;
@@ -842,7 +1164,13 @@
     return str.str();
 }
 
-/** Formatted output of the MagnitudeType type. */
+/** Formatted output of the MagnitudeType type.
+ *
+ * @param[out] os             Output stream
+ * @param[in]  magnitude_type Type to output.
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const MagnitudeType &magnitude_type)
 {
     switch(magnitude_type)
@@ -860,6 +1188,12 @@
     return os;
 }
 
+/** Formatted output of the MagnitudeType type.
+ *
+ * @param[in] type Type to output.
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const arm_compute::MagnitudeType &type)
 {
     std::stringstream str;
@@ -867,7 +1201,13 @@
     return str.str();
 }
 
-/** Formatted output of the GradientDimension type. */
+/** Formatted output of the GradientDimension type.
+ *
+ * @param[out] os  Output stream
+ * @param[in]  dim Type to output
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const GradientDimension &dim)
 {
     switch(dim)
@@ -888,6 +1228,12 @@
     return os;
 }
 
+/** Formatted output of the GradientDimension type.
+ *
+ * @param[in] type Type to output
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const arm_compute::GradientDimension &type)
 {
     std::stringstream str;
@@ -895,7 +1241,13 @@
     return str.str();
 }
 
-/** Formatted output of the HOGNormType type. */
+/** Formatted output of the HOGNormType type.
+ *
+ * @param[out] os        Output stream
+ * @param[in]  norm_type Type to output
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const HOGNormType &norm_type)
 {
     switch(norm_type)
@@ -916,6 +1268,12 @@
     return os;
 }
 
+/** Formatted output of the HOGNormType type.
+ *
+ * @param[in] type Type to output
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const HOGNormType &type)
 {
     std::stringstream str;
@@ -923,7 +1281,13 @@
     return str.str();
 }
 
-/** Formatted output of the Size2D type. */
+/** Formatted output of the Size2D type.
+ *
+ * @param[out] os   Output stream
+ * @param[in]  size Type to output
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const Size2D &size)
 {
     os << size.width << "x" << size.height;
@@ -931,6 +1295,12 @@
     return os;
 }
 
+/** Formatted output of the Size2D type.
+ *
+ * @param[in] type Type to output
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const Size2D &type)
 {
     std::stringstream str;
@@ -938,7 +1308,13 @@
     return str.str();
 }
 
-/** Formatted output of the Size2D type. */
+/** Formatted output of the HOGInfo type.
+ *
+ * @param[out] os       Output stream
+ * @param[in]  hog_info Type to output
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const HOGInfo &hog_info)
 {
     os << "{CellSize=" << hog_info.cell_size() << ","
@@ -953,7 +1329,12 @@
     return os;
 }
 
-/** Formatted output of the HOGInfo type. */
+/** Formatted output of the HOGInfo type.
+ *
+ * @param[in] type Type to output
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const HOGInfo &type)
 {
     std::stringstream str;
@@ -961,6 +1342,13 @@
     return str.str();
 }
 
+/** Formatted output of the ConvolutionMethod type.
+ *
+ * @param[out] os          Output stream
+ * @param[in]  conv_method Type to output
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const ConvolutionMethod &conv_method)
 {
     switch(conv_method)
@@ -981,6 +1369,12 @@
     return os;
 }
 
+/** Formatted output of the ConvolutionMethod type.
+ *
+ * @param[in] conv_method Type to output
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const ConvolutionMethod &conv_method)
 {
     std::stringstream str;
@@ -988,6 +1382,13 @@
     return str.str();
 }
 
+/** Formatted output of the GPUTarget type.
+ *
+ * @param[out] os         Output stream
+ * @param[in]  gpu_target Type to output
+ *
+ * @return Modified output stream.
+ */
 inline ::std::ostream &operator<<(::std::ostream &os, const GPUTarget &gpu_target)
 {
     switch(gpu_target)
@@ -1041,6 +1442,12 @@
     return os;
 }
 
+/** Formatted output of the GPUTarget type.
+ *
+ * @param[in] gpu_target Type to output
+ *
+ * @return Formatted string.
+ */
 inline std::string to_string(const GPUTarget &gpu_target)
 {
     std::stringstream str;
@@ -1048,4 +1455,4 @@
     return str.str();
 }
 } // namespace arm_compute
-#endif /* __ARM_COMPUTE_TEST_TYPE_PRINTER_H__ */
+#endif /* __ARM_COMPUTE_TEST_TYPE_PRINTER_H__ */
\ No newline at end of file