// Copyright 2014 BVLC and contributors.

#include <vector>

#include "caffe/layer.hpp"
#include "caffe/vision_layers.hpp"
#include "caffe/util/math_functions.hpp"

namespace caffe {

	template <typename Dtype>
	void FlattenLayer<Dtype>::SetUp(const vector<Blob<Dtype>*>& bottom,
		vector<Blob<Dtype>*>* top) {
			CHECK_EQ(bottom.size(), 1) << "Flatten Layer takes a single blob as input.";
			CHECK_EQ(top->size(), 1) << "Flatten Layer takes a single blob as output.";
			int channels_out = bottom[0]->channels() * bottom[0]->height()
				* bottom[0]->width();
			(*top)[0]->Reshape(bottom[0]->num(), channels_out, 1, 1);
			count_ = bottom[0]->num() * channels_out;
			CHECK_EQ(count_, bottom[0]->count());
			CHECK_EQ(count_, (*top)[0]->count());
	}

	template <typename Dtype>
	Dtype FlattenLayer<Dtype>::Forward_cpu(const vector<Blob<Dtype>*>& bottom,
		vector<Blob<Dtype>*>* top) {
			(*top)[0]->ShareData(*bottom[0]);
			return Dtype(0.);
	}

	template <typename Dtype>
	void FlattenLayer<Dtype>::Backward_cpu(const vector<Blob<Dtype>*>& top,
		const bool propagate_down, vector<Blob<Dtype>*>* bottom) {
			(*bottom)[0]->ShareDiff(*top[0]);
	}

	INSTANTIATE_CLASS(FlattenLayer);

}  // namespace caffe
