From 33f74de2b4553d9643afca4ad3e4fa6bb169fc5d Mon Sep 17 00:00:00 2001
From: Noiredd <snowball91b@gmail.com>
Date: Wed, 7 Mar 2018 13:57:56 +0100
Subject: [PATCH] PoolingLayer customizable output shape rounding mode

---
 include/caffe/layers/pooling_layer.hpp |  1 +
 src/caffe/layers/pooling_layer.cpp     | 21 +++++++++++++++++----
 src/caffe/proto/caffe.proto            |  6 ++++++
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/include/caffe/layers/pooling_layer.hpp b/include/caffe/layers/pooling_layer.hpp
index f4d6803..38a4328 100644
--- a/include/caffe/layers/pooling_layer.hpp
+++ b/include/caffe/layers/pooling_layer.hpp
@@ -51,6 +51,7 @@ class PoolingLayer : public Layer<Dtype> {
   int height_, width_;
   int pooled_height_, pooled_width_;
   bool global_pooling_;
+  PoolingParameter_RoundMode round_mode_;
   Blob<Dtype> rand_idx_;
   Blob<int> max_idx_;
 };
diff --git a/src/caffe/layers/pooling_layer.cpp b/src/caffe/layers/pooling_layer.cpp
index 90897db..f2a0885 100644
--- a/src/caffe/layers/pooling_layer.cpp
+++ b/src/caffe/layers/pooling_layer.cpp
@@ -35,6 +35,7 @@ void PoolingLayer<Dtype>::LayerSetUp(const vector<Blob<Dtype>*>& bottom,
       || (!pool_param.has_stride_h() && !pool_param.has_stride_w()))
       << "Stride is stride OR stride_h and stride_w are required.";
   global_pooling_ = pool_param.global_pooling();
+  round_mode_ = pool_param.round_mode();
   if (global_pooling_) {
     kernel_h_ = bottom[0]->height();
     kernel_w_ = bottom[0]->width();
@@ -87,10 +88,22 @@ void PoolingLayer<Dtype>::Reshape(const vector<Blob<Dtype>*>& bottom,
     kernel_h_ = bottom[0]->height();
     kernel_w_ = bottom[0]->width();
   }
-  pooled_height_ = static_cast<int>(ceil(static_cast<float>(
-      height_ + 2 * pad_h_ - kernel_h_) / stride_h_)) + 1;
-  pooled_width_ = static_cast<int>(ceil(static_cast<float>(
-      width_ + 2 * pad_w_ - kernel_w_) / stride_w_)) + 1;
+  switch (round_mode_) {
+  case PoolingParameter_RoundMode_CEIL:
+    pooled_height_ = static_cast<int>(ceil(static_cast<float>(
+        height_ + 2 * pad_h_ - kernel_h_) / stride_h_)) + 1;
+    pooled_width_ = static_cast<int>(ceil(static_cast<float>(
+        width_ + 2 * pad_w_ - kernel_w_) / stride_w_)) + 1;
+    break;
+  case PoolingParameter_RoundMode_FLOOR:
+    pooled_height_ = static_cast<int>(floor(static_cast<float>(
+        height_ + 2 * pad_h_ - kernel_h_) / stride_h_)) + 1;
+    pooled_width_ = static_cast<int>(floor(static_cast<float>(
+        width_ + 2 * pad_w_ - kernel_w_) / stride_w_)) + 1;
+    break;
+  default:
+    LOG(FATAL) << "Unknown rounding mode.";
+  }
   if (pad_h_ || pad_w_) {
     // If we have padding, ensure that the last pooling starts strictly
     // inside the image (instead of at the padding); otherwise clip the last.
diff --git a/src/caffe/proto/caffe.proto b/src/caffe/proto/caffe.proto
index 22764ab..cfef3c0 100644
--- a/src/caffe/proto/caffe.proto
+++ b/src/caffe/proto/caffe.proto
@@ -935,6 +935,12 @@ message PoolingParameter {
   // If global_pooling then it will pool over the size of the bottom by doing
   // kernel_h = bottom->height and kernel_w = bottom->width
   optional bool global_pooling = 12 [default = false];
+  // How to calculate the output size - using ceil (default) or floor rounding.
+  enum RoundMode {
+    CEIL = 0;
+    FLOOR = 1;
+  }
+  optional RoundMode round_mode = 13 [default = CEIL];
 }
 
 message PowerParameter {
-- 
2.7.4