From c84a4e510b98a17d8883b928871f315cb30b4cd7 Mon Sep 17 00:00:00 2001
From: iamshnoo <mukherjee.anjishnu@gmail.com>
Date: Tue, 11 Aug 2020 01:01:45 +0530
Subject: [PATCH 01/15] Pixel Shuffle layer. Commit 1.

---
 src/mlpack/methods/ann/layer/CMakeLists.txt   |   2 +
 src/mlpack/methods/ann/layer/layer.hpp        |   1 +
 src/mlpack/methods/ann/layer/layer_types.hpp  |   2 +
 .../methods/ann/layer/pixel_shuffle.hpp       | 179 ++++++++++++++++++
 .../methods/ann/layer/pixel_shuffle_impl.hpp  | 144 ++++++++++++++
 src/mlpack/tests/ann_layer_test.cpp           |  74 ++++++++
 6 files changed, 402 insertions(+)
 create mode 100644 src/mlpack/methods/ann/layer/pixel_shuffle.hpp
 create mode 100644 src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp

diff --git a/src/mlpack/methods/ann/layer/CMakeLists.txt b/src/mlpack/methods/ann/layer/CMakeLists.txt
index c3ae086c87..b4034f580c 100644
--- a/src/mlpack/methods/ann/layer/CMakeLists.txt
+++ b/src/mlpack/methods/ann/layer/CMakeLists.txt
@@ -79,6 +79,8 @@ set(SOURCES
   noisylinear_impl.hpp
   parametric_relu.hpp
   parametric_relu_impl.hpp
+  pixel_shuffle.hpp
+  pixel_shuffle_impl.hpp
   recurrent.hpp
   recurrent_impl.hpp
   recurrent_attention.hpp
diff --git a/src/mlpack/methods/ann/layer/layer.hpp b/src/mlpack/methods/ann/layer/layer.hpp
index 8e8e00691e..6673411616 100644
--- a/src/mlpack/methods/ann/layer/layer.hpp
+++ b/src/mlpack/methods/ann/layer/layer.hpp
@@ -55,6 +55,7 @@
 #include "noisylinear.hpp"
 #include "padding.hpp"
 #include "parametric_relu.hpp"
+#include "pixel_shuffle.hpp"
 #include "recurrent_attention.hpp"
 #include "recurrent.hpp"
 #include "reinforce_normal.hpp"
diff --git a/src/mlpack/methods/ann/layer/layer_types.hpp b/src/mlpack/methods/ann/layer/layer_types.hpp
index 0f52a24df7..9e8dd0ce36 100644
--- a/src/mlpack/methods/ann/layer/layer_types.hpp
+++ b/src/mlpack/methods/ann/layer/layer_types.hpp
@@ -40,6 +40,7 @@
 #include <mlpack/methods/ann/layer/adaptive_max_pooling.hpp>
 #include <mlpack/methods/ann/layer/adaptive_mean_pooling.hpp>
 #include <mlpack/methods/ann/layer/parametric_relu.hpp>
+#include <mlpack/methods/ann/layer/pixel_shuffle.hpp>
 #include <mlpack/methods/ann/layer/reinforce_normal.hpp>
 #include <mlpack/methods/ann/layer/reparametrization.hpp>
 #include <mlpack/methods/ann/layer/select.hpp>
@@ -272,6 +273,7 @@ using LayerTypes = boost::variant<
     NoisyLinear<arma::mat, arma::mat>*,
     Padding<arma::mat, arma::mat>*,
     PReLU<arma::mat, arma::mat>*,
+    PixelShuffle<arma::mat, arma::mat>*,
     Softmax<arma::mat, arma::mat>*,
     TransposedConvolution<NaiveConvolution<ValidConvolution>,
             NaiveConvolution<ValidConvolution>,
diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
new file mode 100644
index 0000000000..27dea9ba38
--- /dev/null
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
@@ -0,0 +1,179 @@
+/**
+ * @file methods/ann/layer/pixel_shuffle.hpp
+ * @author Anjishnu Mukherjee
+ *
+ * Definition of the PixelShuffle class.
+ *
+ * mlpack is free software; you may redistribute it and/or modify it under the
+ * terms of the 3-clause BSD license.  You should have received a copy of the
+ * 3-clause BSD license along with mlpack.  If not, see
+ * http://www.opensource.org/licenses/BSD-3-Clause for more information.
+ */
+#ifndef MLPACK_METHODS_ANN_LAYER_PIXEL_SHUFFLE_HPP
+#define MLPACK_METHODS_ANN_LAYER_PIXEL_SHUFFLE_HPP
+
+#include <mlpack/prereqs.hpp>
+
+namespace mlpack {
+namespace ann /** Artificial Neural Network. */ {
+
+/**
+ * Implementation of the PixelShuffle layer.
+ *
+ * For more information, refer to the following paper,
+ *
+ * @code
+ * @article{Shi16,
+ *   author    = {Wenzhe Shi, Jose Caballero,Ferenc Huszár, Johannes Totz,
+ *               Andrew P. Aitken, Rob Bishop, Daniel Rueckert, Zehan Wang},
+ *   title     = {Real-Time Single Image and Video Super-Resolution Using an
+ *               Efficient Sub-Pixel Convolutional Neural Network},
+ *   journal   = {CoRR},
+ *   volume    = {abs/1609.05158},
+ *   year      = {2016},
+ *   url       = {https://arxiv.org/abs/1609.05158},
+ *   eprint    = {1609.05158},
+ * }
+ * @endcode
+ *
+ * @tparam InputDataType Type of the input data (arma::colvec, arma::mat,
+ *         arma::sp_mat or arma::cube).
+ * @tparam OutputDataType Type of the output data (arma::colvec, arma::mat,
+ *         arma::sp_mat or arma::cube).
+ */
+template <
+    typename InputDataType = arma::mat,
+    typename OutputDataType = arma::mat
+>
+class PixelShuffle
+{
+ public:
+  //! Create the PixelShuffle object.
+  PixelShuffle();
+  /**
+   * Create the PixelShuffle object using the specified parameters.
+   * The number of input channels should be an integral multiple of the square
+   * of the upscale factor.
+   *
+   * @param upscaleFactor The scaling factor for Pixel Shuffle.
+   * @param height The height of each input image.
+   * @param width The width of each input image.
+   * @param size The number of channels of each input image.
+   */
+  PixelShuffle( size_t upscaleFactor,
+                size_t height,
+                size_t width,
+                size_t size);
+
+  /**
+   * Ordinary feed forward pass of the PixelShuffle layer.
+   *
+   * @param input Input data used for evaluating the specified function.
+   * @param output Resulting output activation.
+   */
+  template<typename eT>
+  void Forward(const arma::Mat<eT>& input, arma::Mat<eT>& output);
+
+  /**
+   * Ordinary feed backward pass of the PixelShuffle layer.
+   *
+   * @param * (input) The propagated input activation.
+   * @param gy The backpropagated error.
+   * @param g The calculated gradient.
+   */
+  template<typename eT>
+  void Backward(const arma::Mat<eT>& input,
+                const arma::Mat<eT>& gy,
+                arma::Mat<eT>& g);
+
+  //! Get the output parameter.
+  OutputDataType const& OutputParameter() const { return outputParameter; }
+  //! Modify the output parameter.
+  OutputDataType& OutputParameter() { return outputParameter; }
+
+  //! Get the delta.
+  OutputDataType const& Delta() const { return delta; }
+  //! Modify the delta.
+  OutputDataType& Delta() { return delta; }
+
+  //! Get the upscale factor.
+  size_t UpscaleFactor() const { return upscaleFactor; }
+
+  //! Modify the upscale factor.
+  size_t& UpscaleFactor() { return upscaleFactor; }
+
+  //! Get the input image height.
+  size_t InputHeight() const { return height; }
+
+  //! Modify the input image height.
+  size_t& InputHeight() { return height; }
+
+  //! Get the input image width.
+  size_t InputWidth() const { return width; }
+
+  //! Modify the input image width.
+  size_t& InputWidth() { return width; }
+
+  //! Get the number of input channels.
+  size_t InputChannels() const { return size; }
+
+  //! Modify the number of input channels.
+  size_t& InputChannels() { return size; }
+
+  //! Get the output image height.
+  size_t OutputHeight() const { return outputHeight; }
+
+  //! Get the output image width.
+  size_t OutputWidth() const { return outputWidth; }
+
+  //! Get the number of output channels.
+  size_t OutputChannels() const { return sizeOut; }
+
+  /**
+   * Serialize the layer.
+   */
+  template<typename Archive>
+  void serialize(Archive& ar, const unsigned int /* version */);
+
+ private:
+  //! Locally-stored delta object.
+  OutputDataType delta;
+
+  //! Locally-stored output parameter object.
+  OutputDataType outputParameter;
+
+  //! The scaling factor for Pixel Shuffle.
+  size_t upscaleFactor;
+
+  //! The height of each input image.
+  size_t height;
+
+  //! The width of each input image.
+  size_t width;
+
+  //! The number of channels of each input image.
+  size_t size;
+
+  //! The number of images in the batch.
+  size_t batchSize;
+
+  //! The height of each output image.
+  size_t outputHeight;
+
+  //! The width of each output image.
+  size_t outputWidth;
+
+  //! The number of channels of each output image.
+  size_t sizeOut;
+
+  //! A boolean used to do some internal calculations once initially.
+  bool reset;
+}; // class PixelShuffle
+
+} // namespace ann
+} // namespace mlpack
+
+// Include implementation.
+#include "pixel_shuffle_impl.hpp"
+
+#endif
diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
new file mode 100644
index 0000000000..cfbd4287b9
--- /dev/null
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -0,0 +1,144 @@
+/**
+ * @file methods/ann/layer/pixel_shuffle_impl.hpp
+ * @author Anjishnu Mukherjee
+ *
+ * Implementation of the PixelShuffle class.
+ *
+ * mlpack is free software; you may redistribute it and/or modify it under the
+ * terms of the 3-clause BSD license.  You should have received a copy of the
+ * 3-clause BSD license along with mlpack.  If not, see
+ * http://www.opensource.org/licenses/BSD-3-Clause for more information.
+ */
+#ifndef MLPACK_METHODS_ANN_LAYER_PIXEL_SHUFFLE_IMPL_HPP
+#define MLPACK_METHODS_ANN_LAYER_PIXEL_SHUFFLE_IMPL_HPP
+
+// In case it hasn't yet been included.
+#include "pixel_shuffle.hpp"
+
+namespace mlpack {
+namespace ann /** Artificial Neural Network. */ {
+
+template<typename InputDataType, typename OutputDataType>
+PixelShuffle<InputDataType, OutputDataType>::PixelShuffle() :
+    upscaleFactor(0),
+    height(0),
+    width(0),
+    size(0),
+    reset(false)
+{
+  // Nothing to do here.
+}
+
+template<typename InputDataType, typename OutputDataType>
+PixelShuffle<InputDataType, OutputDataType>::PixelShuffle(
+    size_t upscaleFactor,
+    size_t height,
+    size_t width,
+    size_t size) :
+    upscaleFactor(upscaleFactor),
+    height(height),
+    width(width),
+    size(size),
+    reset(false)
+{
+  // Nothing to do here.
+}
+
+template<typename InputDataType, typename OutputDataType>
+template<typename eT>
+void PixelShuffle<InputDataType, OutputDataType>::Forward(
+  const arma::Mat<eT>& input, arma::Mat<eT>& output)
+{
+  if(!reset)
+  {
+    batchSize = input.n_cols;
+    sizeOut = size / std::pow(upscaleFactor, 2);
+    outputHeight = height * upscaleFactor;
+    outputWidth = width * upscaleFactor;
+    reset = true;
+  }
+  output.zeros(outputHeight * outputWidth * sizeOut, batchSize);
+  for(size_t n = 0; n < batchSize; n++)
+  {
+    arma::mat inputImage = input.col(n);
+    arma::mat outputImage = output.col(n);
+    arma::cube inputTemp(const_cast<arma::mat&>(inputImage).memptr(), height,
+        width, size, false, false);
+    arma::cube outputTemp(const_cast<arma::mat&>(outputImage).memptr(),
+        outputHeight, outputWidth, sizeOut, false, false);
+
+    for (size_t c = 0; c < sizeOut ; c++)
+    {
+      for (size_t h = 0; h < outputHeight; h++)
+      {
+        for (size_t w = 0; w < outputWidth; w++)
+        {
+          size_t height_index = h / upscaleFactor;
+          size_t width_index = w / upscaleFactor;
+          size_t channel_index = (upscaleFactor * (h % upscaleFactor)) +
+              (w % upscaleFactor) + (c * std::pow(upscaleFactor, 2));
+          outputTemp(w, h, c) = inputTemp(width_index, height_index,
+              channel_index);
+        }
+      }
+    }
+    output.col(n) = outputImage;
+  }
+}
+
+template<typename InputDataType, typename OutputDataType>
+template<typename eT>
+void PixelShuffle<InputDataType, OutputDataType>::Backward(
+    const arma::Mat<eT>& input, const arma::Mat<eT>& gy, arma::Mat<eT>& g)
+{
+  g.zeros(arma::size(input));
+  for(size_t n = 0; n < batchSize; n++)
+  {
+    arma::mat gyImage = gy.col(n);
+    arma::mat gImage = g.col(n);
+    arma::cube gyTemp(const_cast<arma::mat&>(gyImage).memptr(), outputHeight,
+        outputWidth, sizeOut, false, false);
+    arma::cube gTemp(const_cast<arma::mat&>(gImage).memptr(), height, width,
+        size, false, false);
+
+    for (size_t c = 0; c < sizeOut ; c++)
+    {
+      for (size_t h = 0; h < outputHeight; h++)
+      {
+        for (size_t w = 0; w < outputWidth; w++)
+        {
+          size_t height_index = h / upscaleFactor;
+          size_t width_index = w / upscaleFactor;
+          size_t channel_index = (upscaleFactor * (h % upscaleFactor)) +
+              (w % upscaleFactor) + (c * std::pow(upscaleFactor, 2));
+          gTemp(width_index, height_index, channel_index) = gyTemp(w, h, c);
+        }
+      }
+    }
+
+    g.col(n) = gImage;
+  }
+}
+
+template<typename InputDataType, typename OutputDataType>
+template<typename Archive>
+void PixelShuffle<InputDataType, OutputDataType>::serialize(
+    Archive& ar,
+    const unsigned int /* version */)
+{
+  ar & BOOST_SERIALIZATION_NVP(delta);
+  ar & BOOST_SERIALIZATION_NVP(outputParameter);
+  ar & BOOST_SERIALIZATION_NVP(upscaleFactor);
+  ar & BOOST_SERIALIZATION_NVP(height);
+  ar & BOOST_SERIALIZATION_NVP(width);
+  ar & BOOST_SERIALIZATION_NVP(size);
+  ar & BOOST_SERIALIZATION_NVP(batchSize);
+  ar & BOOST_SERIALIZATION_NVP(outputHeight);
+  ar & BOOST_SERIALIZATION_NVP(outputWidth);
+  ar & BOOST_SERIALIZATION_NVP(sizeOut);
+}
+
+} // namespace ann
+} // namespace mlpack
+
+#endif
diff --git a/src/mlpack/tests/ann_layer_test.cpp b/src/mlpack/tests/ann_layer_test.cpp
index 29e16273b8..38fec13c05 100644
--- a/src/mlpack/tests/ann_layer_test.cpp
+++ b/src/mlpack/tests/ann_layer_test.cpp
@@ -4186,3 +4186,77 @@ TEST_CASE("BatchNormDeterministicTest", "[ANNLayerTest]")
   // The model should switch to training mode for predicting.
   REQUIRE(boost::get<BatchNorm<>*>(module.Model()[0])->Deterministic() == 0);
 }
+
+/**
+ * Simple Test for PixelShuffle layer.
+ */
+TEST_CASE("PixelShuffleLayerTest", "[ANNLayerTest]")
+{
+  arma::mat input, output, gy, g, outputExpected, gExpected;
+  PixelShuffle<> module(2, 2, 2, 4);
+
+  // Input is a batch of 2 images, each of size (2,2) and having 4 channels.
+  input << 1 << 3 << 2 << 4 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0
+      << 0 << 0 << arma::endr << 5 << 7 << 6 << 8 << 0 << 0 << 0 << 0 << 0 << 0
+      << 0 << 0 << 0 << 0 << 0 << 0 << arma::endr;
+
+  gy << 1 << 5 << 9 << 13 << 2 << 6 << 10 << 14 << 3 << 7 << 11 << 15 << 4 << 8
+      << 12 << 16 << arma::endr << 17 << 21 << 25 << 29 << 18 << 22 << 26 << 30
+      << 19 << 23 << 27 << 31 << 20 << 24 << 28 << 32 << arma::endr;
+
+  // Calculated using torch.nn.PixelShuffle().
+  outputExpected << 1 << 0 << 3 << 0 << 0 << 0 << 0 << 0 << 2 << 0 << 4 << 0
+      << 0 << 0 << 0 << 0 << arma::endr << 5 << 0 << 7 << 0 << 0 << 0 << 0 << 0
+      << 6 << 0 << 8 << 0 << 0 << 0 << 0 << 0 << arma::endr;
+  gExpected << 1 << 9 << 3 << 11 << 5 << 13 << 7 << 15 << 2 << 10 << 4 << 12
+      << 6 << 14 << 8 << 16 << arma::endr << 17 << 25 << 19 << 27 << 21 << 29
+      << 23 << 31 << 18 << 26 << 20 << 28 << 22 << 30 << 24 << 32 << arma::endr;
+
+  input = input.t();
+  outputExpected = outputExpected.t();
+  gy = gy.t();
+  gExpected = gExpected.t();
+
+  // Check the Forward pass of the layer.
+  module.Forward(input, output);
+  CheckMatrices(output, outputExpected);
+
+  // Check the Backward pass of the layer.
+  module.Backward(input, gy, g);
+  CheckMatrices(g, gExpected);
+}
+
+/**
+ * Test that the function that can access the parameters of the
+ * PixelShuffle layer works.
+ */
+TEST_CASE("PixelShuffleLayerParametersTest", "[ANNLayerTest]")
+{
+  // Create the layer using the empty constructor.
+  PixelShuffle<> layer;
+
+  // Set the different input parameters of the layer.
+  layer.UpscaleFactor() = 2;
+  layer.InputHeight() = 2;
+  layer.InputWidth() = 2;
+  layer.InputChannels() = 4;
+
+  // Make sure we can get the parameters successfully.
+  REQUIRE(layer.UpscaleFactor() == 2);
+  REQUIRE(layer.InputHeight() == 2);
+  REQUIRE(layer.InputWidth() == 2);
+  REQUIRE(layer.InputChannels() == 4);
+
+  arma::mat input, output;
+  // Input is a batch of 2 images, each of size (2,2) and having 4 channels.
+  input << 1 << 3 << 2 << 4 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0
+      << 0 << 0 << arma::endr << 5 << 7 << 6 << 8 << 0 << 0 << 0 << 0 << 0 << 0
+      << 0 << 0 << 0 << 0 << 0 << 0 << arma::endr;
+  input = input.t();
+  layer.Forward(input, output);
+
+  // Check whether output parameters are returned correctly.
+  REQUIRE(layer.OutputHeight() == 4 );
+  REQUIRE(layer.OutputWidth() == 4);
+  REQUIRE(layer.OutputChannels() == 1);
+}

From 64dd26145a1b1c02593c105a10e2622d1aa33634 Mon Sep 17 00:00:00 2001
From: iamshnoo <mukherjee.anjishnu@gmail.com>
Date: Fri, 14 Aug 2020 19:08:50 +0530
Subject: [PATCH 02/15] Fix style issues.

---
 src/mlpack/methods/ann/layer/pixel_shuffle.hpp      | 10 +++++-----
 src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp |  6 +++---
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
index 27dea9ba38..2fda7cf5f4 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
@@ -60,10 +60,10 @@ class PixelShuffle
    * @param width The width of each input image.
    * @param size The number of channels of each input image.
    */
-  PixelShuffle( size_t upscaleFactor,
-                size_t height,
-                size_t width,
-                size_t size);
+  PixelShuffle(size_t upscaleFactor,
+               size_t height,
+               size_t width,
+               size_t size);
 
   /**
    * Ordinary feed forward pass of the PixelShuffle layer.
@@ -77,7 +77,7 @@ class PixelShuffle
   /**
    * Ordinary feed backward pass of the PixelShuffle layer.
    *
-   * @param * (input) The propagated input activation.
+   * @param input The propagated input activation.
    * @param gy The backpropagated error.
    * @param g The calculated gradient.
    */
diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index cfbd4287b9..3ca2852074 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -49,7 +49,7 @@ template<typename eT>
 void PixelShuffle<InputDataType, OutputDataType>::Forward(
   const arma::Mat<eT>& input, arma::Mat<eT>& output)
 {
-  if(!reset)
+  if (!reset)
   {
     batchSize = input.n_cols;
     sizeOut = size / std::pow(upscaleFactor, 2);
@@ -58,7 +58,7 @@ void PixelShuffle<InputDataType, OutputDataType>::Forward(
     reset = true;
   }
   output.zeros(outputHeight * outputWidth * sizeOut, batchSize);
-  for(size_t n = 0; n < batchSize; n++)
+  for (size_t n = 0; n < batchSize; n++)
   {
     arma::mat inputImage = input.col(n);
     arma::mat outputImage = output.col(n);
@@ -92,7 +92,7 @@ void PixelShuffle<InputDataType, OutputDataType>::Backward(
     const arma::Mat<eT>& input, const arma::Mat<eT>& gy, arma::Mat<eT>& g)
 {
   g.zeros(arma::size(input));
-  for(size_t n = 0; n < batchSize; n++)
+  for (size_t n = 0; n < batchSize; n++)
   {
     arma::mat gyImage = gy.col(n);
     arma::mat gImage = g.col(n);

From 5da525cde653ee3ed2bd5c4c979bdacdbd9b7959 Mon Sep 17 00:00:00 2001
From: iamshnoo <mukherjee.anjishnu@gmail.com>
Date: Fri, 14 Aug 2020 23:49:48 +0530
Subject: [PATCH 03/15] Fix consistency issue for constructor format.

---
 src/mlpack/methods/ann/layer/pixel_shuffle.hpp      | 8 ++++----
 src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
index 2fda7cf5f4..c62b0f0ecb 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
@@ -60,10 +60,10 @@ class PixelShuffle
    * @param width The width of each input image.
    * @param size The number of channels of each input image.
    */
-  PixelShuffle(size_t upscaleFactor,
-               size_t height,
-               size_t width,
-               size_t size);
+  PixelShuffle(const size_t upscaleFactor,
+               const size_t height,
+               const size_t width,
+               const size_t size);
 
   /**
    * Ordinary feed forward pass of the PixelShuffle layer.
diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index 3ca2852074..d65a0c456d 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -31,10 +31,10 @@ PixelShuffle<InputDataType, OutputDataType>::PixelShuffle() :
 
 template<typename InputDataType, typename OutputDataType>
 PixelShuffle<InputDataType, OutputDataType>::PixelShuffle(
-    size_t upscaleFactor,
-    size_t height,
-    size_t width,
-    size_t size) :
+    const size_t upscaleFactor,
+    const size_t height,
+    const size_t width,
+    const size_t size) :
     upscaleFactor(upscaleFactor),
     height(height),
     width(width),

From 438cc009898dad31326636af9f3d47d908ced4af Mon Sep 17 00:00:00 2001
From: iamshnoo <mukherjee.anjishnu@gmail.com>
Date: Tue, 25 Aug 2020 11:47:28 +0530
Subject: [PATCH 04/15] Use suggestions from code review.

---
 .../methods/ann/layer/pixel_shuffle_impl.hpp  |  1 -
 src/mlpack/tests/ann_layer_test.cpp           | 56 ++++++++++++++-----
 2 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index d65a0c456d..31d137eb59 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -115,7 +115,6 @@ void PixelShuffle<InputDataType, OutputDataType>::Backward(
         }
       }
     }
-
     g.col(n) = gImage;
   }
 }
diff --git a/src/mlpack/tests/ann_layer_test.cpp b/src/mlpack/tests/ann_layer_test.cpp
index c3c0b11edc..a1ed47db97 100644
--- a/src/mlpack/tests/ann_layer_test.cpp
+++ b/src/mlpack/tests/ann_layer_test.cpp
@@ -4302,38 +4302,64 @@ TEST_CASE("TransposedConvolutionWeightInitializationTest", "[ANNLayerTest]")
  */
 TEST_CASE("PixelShuffleLayerTest", "[ANNLayerTest]")
 {
-  arma::mat input, output, gy, g, outputExpected, gExpected;
-  PixelShuffle<> module(2, 2, 2, 4);
+  arma::mat input1, output1, gy1, g1, outputExpected1, gExpected1;
+  arma::mat input2, output2, gy2, g2, outputExpected2, gExpected2;
+  PixelShuffle<> module1(2, 2, 2, 4);
+  PixelShuffle<> module2(2, 2, 2, 4);
+
+  // Input is a single image, of size (2,2) and having 4 channels.
+  input1 << 1 << 3 << 2 << 4 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0
+      << 0 << 0 << arma::endr;
+  gy1 << 1 << 5 << 9 << 13 << 2 << 6 << 10 << 14 << 3 << 7 << 11 << 15 << 4 << 8
+      << 12 << 16 << arma::endr;
+
+  // Calculated using torch.nn.PixelShuffle().
+  outputExpected1 << 1 << 0 << 3 << 0 << 0 << 0 << 0 << 0 << 2 << 0 << 4 << 0
+      << 0 << 0 << 0 << 0 << arma::endr;
+  gExpected1 << 1 << 9 << 3 << 11 << 5 << 13 << 7 << 15 << 2 << 10 << 4 << 12
+      << 6 << 14 << 8 << 16 << arma::endr;
+
+  input1 = input1.t();
+  outputExpected1 = outputExpected1.t();
+  gy1 = gy1.t();
+  gExpected1 = gExpected1.t();
+
+  // Check the Forward pass of the layer.
+  module1.Forward(input1, output1);
+  CheckMatrices(output1, outputExpected1);
+
+  // Check the Backward pass of the layer.
+  module1.Backward(input1, gy1, g1);
+  CheckMatrices(g1, gExpected1);
 
   // Input is a batch of 2 images, each of size (2,2) and having 4 channels.
-  input << 1 << 3 << 2 << 4 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0
+  input2 << 1 << 3 << 2 << 4 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0 << 0
       << 0 << 0 << arma::endr << 5 << 7 << 6 << 8 << 0 << 0 << 0 << 0 << 0 << 0
       << 0 << 0 << 0 << 0 << 0 << 0 << arma::endr;
-
-  gy << 1 << 5 << 9 << 13 << 2 << 6 << 10 << 14 << 3 << 7 << 11 << 15 << 4 << 8
+  gy2 << 1 << 5 << 9 << 13 << 2 << 6 << 10 << 14 << 3 << 7 << 11 << 15 << 4 << 8
       << 12 << 16 << arma::endr << 17 << 21 << 25 << 29 << 18 << 22 << 26 << 30
       << 19 << 23 << 27 << 31 << 20 << 24 << 28 << 32 << arma::endr;
 
   // Calculated using torch.nn.PixelShuffle().
-  outputExpected << 1 << 0 << 3 << 0 << 0 << 0 << 0 << 0 << 2 << 0 << 4 << 0
+  outputExpected2 << 1 << 0 << 3 << 0 << 0 << 0 << 0 << 0 << 2 << 0 << 4 << 0
       << 0 << 0 << 0 << 0 << arma::endr << 5 << 0 << 7 << 0 << 0 << 0 << 0 << 0
       << 6 << 0 << 8 << 0 << 0 << 0 << 0 << 0 << arma::endr;
-  gExpected << 1 << 9 << 3 << 11 << 5 << 13 << 7 << 15 << 2 << 10 << 4 << 12
+  gExpected2 << 1 << 9 << 3 << 11 << 5 << 13 << 7 << 15 << 2 << 10 << 4 << 12
       << 6 << 14 << 8 << 16 << arma::endr << 17 << 25 << 19 << 27 << 21 << 29
       << 23 << 31 << 18 << 26 << 20 << 28 << 22 << 30 << 24 << 32 << arma::endr;
 
-  input = input.t();
-  outputExpected = outputExpected.t();
-  gy = gy.t();
-  gExpected = gExpected.t();
+  input2 = input2.t();
+  outputExpected2 = outputExpected2.t();
+  gy2 = gy2.t();
+  gExpected2 = gExpected2.t();
 
   // Check the Forward pass of the layer.
-  module.Forward(input, output);
-  CheckMatrices(output, outputExpected);
+  module2.Forward(input2, output2);
+  CheckMatrices(output2, outputExpected2);
 
   // Check the Backward pass of the layer.
-  module.Backward(input, gy, g);
-  CheckMatrices(g, gExpected);
+  module2.Backward(input2, gy2, g2);
+  CheckMatrices(g2, gExpected2);
 }
 
 /**

From c6cd6b860c3e56c76c2df9abe0bfe17c3bf7d1e1 Mon Sep 17 00:00:00 2001
From: iamshnoo <mukherjee.anjishnu@gmail.com>
Date: Tue, 25 Aug 2020 16:25:52 +0530
Subject: [PATCH 05/15] FIx static analysis issue.

---
 src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index 31d137eb59..796ee54071 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -24,6 +24,10 @@ PixelShuffle<InputDataType, OutputDataType>::PixelShuffle() :
     height(0),
     width(0),
     size(0),
+    batchSize(0),
+    outputHeight(0),
+    outputWidth(0),
+    sizeOut(0),
     reset(false)
 {
   // Nothing to do here.
@@ -39,6 +43,10 @@ PixelShuffle<InputDataType, OutputDataType>::PixelShuffle(
     height(height),
     width(width),
     size(size),
+    batchSize(0),
+    outputHeight(0),
+    outputWidth(0),
+    sizeOut(0),
     reset(false)
 {
   // Nothing to do here.

From cbb151000528700e9c57933030fc71e4c0803b70 Mon Sep 17 00:00:00 2001
From: iamshnoo <mukherjee.anjishnu@gmail.com>
Date: Wed, 26 Aug 2020 09:46:37 +0530
Subject: [PATCH 06/15] Update HISTORY.md for Pixel Shuffle layer.

---
 HISTORY.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/HISTORY.md b/HISTORY.md
index c04b2aeca1..ba5bb0b194 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,5 +1,7 @@
 ### mlpack ?.?.?
 ###### ????-??-??
+  * Added Pixel Shuffle layer (#2563).
+
   * Force CMake to show error when it didn't find Python/modules (#2568).
 
   * Refactor `ProgramInfo()` to separate out all the different

From 1ae6336ab4d49cb56c2f30ae1796542ed5407d99 Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Fri, 12 Feb 2021 05:17:23 +0530
Subject: [PATCH 07/15] Update pixel_shuffle_impl.hpp

Updated Cereal_nvp
---
 .../methods/ann/layer/pixel_shuffle_impl.hpp  | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index 796ee54071..17c7c93980 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -133,16 +133,17 @@ void PixelShuffle<InputDataType, OutputDataType>::serialize(
     Archive& ar,
     const unsigned int /* version */)
 {
-  ar & BOOST_SERIALIZATION_NVP(delta);
-  ar & BOOST_SERIALIZATION_NVP(outputParameter);
-  ar & BOOST_SERIALIZATION_NVP(upscaleFactor);
-  ar & BOOST_SERIALIZATION_NVP(height);
-  ar & BOOST_SERIALIZATION_NVP(width);
-  ar & BOOST_SERIALIZATION_NVP(size);
-  ar & BOOST_SERIALIZATION_NVP(batchSize);
-  ar & BOOST_SERIALIZATION_NVP(outputHeight);
-  ar & BOOST_SERIALIZATION_NVP(outputWidth);
-  ar & BOOST_SERIALIZATION_NVP(sizeOut);
+  ar(CEREAL_NVP(delta));
+  ar(CEREAL_NVP(outputParameter));
+  ar(CEREAL_NVP(upscaleFactor));
+  ar(CEREAL_NVP(height));
+  ar(CEREAL_NVP(width));
+  ar(CEREAL_NVP(size));
+  ar(CEREAL_NVP(batchSize));
+  ar(CEREAL_NVP(outputHeight));
+  ar(CEREAL_NVP(outputHeight));
+  ar(CEREAL_NVP(outputWidth));
+  ar(CEREAL_NVP(sizeOut));
 }
 
 } // namespace ann

From 1aae47ae0b3cc35bb5aff54d9f4a12f4f70a939f Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Fri, 12 Feb 2021 06:36:04 +0530
Subject: [PATCH 08/15] Update layer_types.hpp

Added pixel shuffle to more_types
---
 src/mlpack/methods/ann/layer/layer_types.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mlpack/methods/ann/layer/layer_types.hpp b/src/mlpack/methods/ann/layer/layer_types.hpp
index 14bac39a81..c1e1987f70 100644
--- a/src/mlpack/methods/ann/layer/layer_types.hpp
+++ b/src/mlpack/methods/ann/layer/layer_types.hpp
@@ -220,6 +220,7 @@ class AdaptiveMeanPooling;
 
 using MoreTypes = boost::variant<
         Linear3D<arma::mat, arma::mat, NoRegularizer>*,
+        PixelShuffle<arma::mat, arma::mat>*,
         Glimpse<arma::mat, arma::mat>*,
         Highway<arma::mat, arma::mat>*,
         MultiheadAttention<arma::mat, arma::mat, NoRegularizer>*,
@@ -290,7 +291,6 @@ using LayerTypes = boost::variant<
     NoisyLinear<arma::mat, arma::mat>*,
     Padding<arma::mat, arma::mat>*,
     PReLU<arma::mat, arma::mat>*,
-    PixelShuffle<arma::mat, arma::mat>*,
     Softmax<arma::mat, arma::mat>*,
     SpatialDropout<arma::mat, arma::mat>*,
     TransposedConvolution<NaiveConvolution<ValidConvolution>,

From 7b70a820f8511d58ecfabcbcca71b14732ca585b Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Mon, 15 Feb 2021 02:37:02 +0530
Subject: [PATCH 09/15] Code  style fix

Co-authored-by: kartikdutt18 <39593019+kartikdutt18@users.noreply.github.com>
---
 src/mlpack/methods/ann/layer/pixel_shuffle.hpp      |  1 +
 src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp | 13 ++++---------
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
index c62b0f0ecb..48d89c2fe2 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
@@ -50,6 +50,7 @@ class PixelShuffle
  public:
   //! Create the PixelShuffle object.
   PixelShuffle();
+
   /**
    * Create the PixelShuffle object using the specified parameters.
    * The number of input channels should be an integral multiple of the square
diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index 17c7c93980..9edb09c2eb 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -20,15 +20,7 @@ namespace ann /** Artificial Neural Network. */ {
 
 template<typename InputDataType, typename OutputDataType>
 PixelShuffle<InputDataType, OutputDataType>::PixelShuffle() :
-    upscaleFactor(0),
-    height(0),
-    width(0),
-    size(0),
-    batchSize(0),
-    outputHeight(0),
-    outputWidth(0),
-    sizeOut(0),
-    reset(false)
+    PixelShuffle(0, 0, 0, 0)
 {
   // Nothing to do here.
 }
@@ -65,6 +57,7 @@ void PixelShuffle<InputDataType, OutputDataType>::Forward(
     outputWidth = width * upscaleFactor;
     reset = true;
   }
+
   output.zeros(outputHeight * outputWidth * sizeOut, batchSize);
   for (size_t n = 0; n < batchSize; n++)
   {
@@ -90,6 +83,7 @@ void PixelShuffle<InputDataType, OutputDataType>::Forward(
         }
       }
     }
+
     output.col(n) = outputImage;
   }
 }
@@ -123,6 +117,7 @@ void PixelShuffle<InputDataType, OutputDataType>::Backward(
         }
       }
     }
+
     g.col(n) = gImage;
   }
 }

From 5e695f99c8ea389fcf9b08080c51ce8b0ecc5ad9 Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Tue, 23 Feb 2021 13:55:23 +0530
Subject: [PATCH 10/15] Removed  copying

---
 .../methods/ann/layer/pixel_shuffle_impl.hpp      | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index 9edb09c2eb..89ae8b79d5 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -61,12 +61,10 @@ void PixelShuffle<InputDataType, OutputDataType>::Forward(
   output.zeros(outputHeight * outputWidth * sizeOut, batchSize);
   for (size_t n = 0; n < batchSize; n++)
   {
-    arma::mat inputImage = input.col(n);
-    arma::mat outputImage = output.col(n);
-    arma::cube inputTemp(const_cast<arma::mat&>(inputImage).memptr(), height,
-        width, size, false, false);
-    arma::cube outputTemp(const_cast<arma::mat&>(outputImage).memptr(),
-        outputHeight, outputWidth, sizeOut, false, false);
+    arma::cube inputTemp(const_cast<arma::mat&>(input).memptr(), height,
+        width, size * batchSize, false, false);
+    arma::cube outputTemp(const_cast<arma::mat&>(output).memptr(),
+        outputHeight, outputWidth, sizeOut * batchSize, false, false);
 
     for (size_t c = 0; c < sizeOut ; c++)
     {
@@ -78,13 +76,12 @@ void PixelShuffle<InputDataType, OutputDataType>::Forward(
           size_t width_index = w / upscaleFactor;
           size_t channel_index = (upscaleFactor * (h % upscaleFactor)) +
               (w % upscaleFactor) + (c * std::pow(upscaleFactor, 2));
-          outputTemp(w, h, c) = inputTemp(width_index, height_index,
-              channel_index);
+          outputTemp(w, h, c + n * sizeOut) = inputTemp(width_index, height_index,
+              channel_index + n * size);
         }
       }
     }
 
-    output.col(n) = outputImage;
   }
 }
 

From 4eff650f9d90b236139117b4c6a69acfbb8f0329 Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Tue, 23 Feb 2021 15:16:44 +0530
Subject: [PATCH 11/15]      Remove copying in backward function.

---
 .../methods/ann/layer/pixel_shuffle_impl.hpp   | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index 89ae8b79d5..7bcf985f45 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -66,7 +66,7 @@ void PixelShuffle<InputDataType, OutputDataType>::Forward(
     arma::cube outputTemp(const_cast<arma::mat&>(output).memptr(),
         outputHeight, outputWidth, sizeOut * batchSize, false, false);
 
-    for (size_t c = 0; c < sizeOut ; c++)
+    for (size_t c = 0; c < sizeOut; c++)
     {
       for (size_t h = 0; h < outputHeight; h++)
       {
@@ -93,14 +93,12 @@ void PixelShuffle<InputDataType, OutputDataType>::Backward(
   g.zeros(arma::size(input));
   for (size_t n = 0; n < batchSize; n++)
   {
-    arma::mat gyImage = gy.col(n);
-    arma::mat gImage = g.col(n);
-    arma::cube gyTemp(const_cast<arma::mat&>(gyImage).memptr(), outputHeight,
-        outputWidth, sizeOut, false, false);
-    arma::cube gTemp(const_cast<arma::mat&>(gImage).memptr(), height, width,
-        size, false, false);
+    arma::cube gyTemp(const_cast<arma::mat&>(gy).memptr(), outputHeight,
+        outputWidth, sizeOut * batchSize, false, false);
+    arma::cube gTemp(const_cast<arma::mat&>(g).memptr(), height, width,
+        size * batchSize, false, false);
 
-    for (size_t c = 0; c < sizeOut ; c++)
+    for (size_t c = 0; c < sizeOut; c++)
     {
       for (size_t h = 0; h < outputHeight; h++)
       {
@@ -110,12 +108,12 @@ void PixelShuffle<InputDataType, OutputDataType>::Backward(
           size_t width_index = w / upscaleFactor;
           size_t channel_index = (upscaleFactor * (h % upscaleFactor)) +
               (w % upscaleFactor) + (c * std::pow(upscaleFactor, 2));
-          gTemp(width_index, height_index, channel_index) = gyTemp(w, h, c);
+          gTemp(width_index, height_index, channel_index + n * sizeOut) = gyTemp(w, h,
+              c + n * size);
         }
       }
     }
 
-    g.col(n) = gImage;
   }
 }
 

From 4f9eb2845c7d2f94886ead42119e2be2c97f8561 Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Tue, 23 Feb 2021 16:47:45 +0530
Subject: [PATCH 12/15] Update pixel_shuffle_impl.hpp

---
 src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index 7bcf985f45..c062c2a029 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -76,8 +76,8 @@ void PixelShuffle<InputDataType, OutputDataType>::Forward(
           size_t width_index = w / upscaleFactor;
           size_t channel_index = (upscaleFactor * (h % upscaleFactor)) +
               (w % upscaleFactor) + (c * std::pow(upscaleFactor, 2));
-          outputTemp(w, h, c + n * sizeOut) = inputTemp(width_index, height_index,
-              channel_index + n * size);
+          outputTemp(w, h, c + n * size) = inputTemp(width_index, height_index,
+              channel_index + n * sizeOut);
         }
       }
     }

From cd167d98ad75c45bb9ef72589807450a51ce57a4 Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Tue, 23 Feb 2021 18:13:32 +0530
Subject: [PATCH 13/15] Update pixel_shuffle_impl.hpp

---
 src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index c062c2a029..7aa976e4d6 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -76,8 +76,8 @@ void PixelShuffle<InputDataType, OutputDataType>::Forward(
           size_t width_index = w / upscaleFactor;
           size_t channel_index = (upscaleFactor * (h % upscaleFactor)) +
               (w % upscaleFactor) + (c * std::pow(upscaleFactor, 2));
-          outputTemp(w, h, c + n * size) = inputTemp(width_index, height_index,
-              channel_index + n * sizeOut);
+          outputTemp(w, h, c + n * sizeOut) = inputTemp(width_index, height_index,
+              channel_index + n * size);
         }
       }
     }
@@ -108,8 +108,8 @@ void PixelShuffle<InputDataType, OutputDataType>::Backward(
           size_t width_index = w / upscaleFactor;
           size_t channel_index = (upscaleFactor * (h % upscaleFactor)) +
               (w % upscaleFactor) + (c * std::pow(upscaleFactor, 2));
-          gTemp(width_index, height_index, channel_index + n * sizeOut) = gyTemp(w, h,
-              c + n * size);
+          gTemp(width_index, height_index, channel_index + n * size) = gyTemp(w, h,
+              c + n * sizeOut);
         }
       }
     }

From 95e756dbb4f5e400dd58e2d7ba71a1088915be14 Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Thu, 25 Feb 2021 18:15:22 +0530
Subject: [PATCH 14/15] Adding co-author

---
 src/mlpack/methods/ann/layer/pixel_shuffle.hpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
index 48d89c2fe2..f425d7c508 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle.hpp
@@ -1,6 +1,7 @@
 /**
  * @file methods/ann/layer/pixel_shuffle.hpp
  * @author Anjishnu Mukherjee
+ * @author Abhinav Anand
  *
  * Definition of the PixelShuffle class.
  *

From 6e040a48aebb4ec213e069473e81798c1a418a09 Mon Sep 17 00:00:00 2001
From: abh2k <41710346+abh2k@users.noreply.github.com>
Date: Thu, 25 Feb 2021 18:16:42 +0530
Subject: [PATCH 15/15]       Adding co-author

---
 src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
index 7aa976e4d6..f56f708981 100644
--- a/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
+++ b/src/mlpack/methods/ann/layer/pixel_shuffle_impl.hpp
@@ -1,6 +1,7 @@
 /**
  * @file methods/ann/layer/pixel_shuffle_impl.hpp
  * @author Anjishnu Mukherjee
+ * @author Abhinav Anand
  *
  * Implementation of the PixelShuffle class.
  *