/*Copyright 2014 Francisco Alvaro

This file is part of SESHAT.

  SESHAT is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  SESHAT is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with SESHAT.  If not, see <http://www.gnu.org/licenses/>.


This file is a modification of the RNNLIB original software covered by
the following copyright and permission notice:

*/
/*Copyright 2009,2010 Alex Graves

This file is part of RNNLIB.

RNNLIB is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

RNNLIB is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with RNNLIB.  If not, see <http://www.gnu.org/licenses/>.*/

#ifndef _INCLUDED_GatherLayer_h  
#define _INCLUDED_GatherLayer_h  

#include "Layer.hpp"

struct GatherLayer: public Layer
{
	//data
	vector<Layer*> sources;
		
	//functions
  GatherLayer(const string& name, vector<Layer*>& srcs, WeightContainer *weight, DataExportHandler *deh):
    Layer(name, srcs.front()->num_seq_dims(), 0, get_size(srcs), weight, deh, srcs.front()),
		sources(srcs)
	{
		source = sources.front();
		wc->new_parameters(0, source->name, name, source->name + "_to_" + name);
		display(outputActivations, "activations");
		display(outputErrors, "errors");
	}
	int get_size(vector<Layer*>& srcs)
	{
		int size = 0;
		for (int i = 0; i < srcs.size(); ++i)
		{
			size += srcs[i]->output_size();
		}
		return size;
	}
	void feed_forward(const vector<int>& outCoords)
	{
		real_t* actBegin = outputActivations[outCoords].begin();
		LOOP(Layer* l, sources)
		{
			View<real_t> inActs = l->outputActivations[outCoords];
			copy(inActs.begin(), inActs.end(), actBegin);
			actBegin += inActs.size();
		}
	}
	void feed_back(const vector<int>& outCoords)
	{
		real_t* errBegin = outputErrors[outCoords].begin();
		LOOP(Layer* l, sources)
		{
			View<real_t> inErrs = l->outputErrors[outCoords];
			int dist = inErrs.size();
			copy(errBegin, errBegin + dist, inErrs.begin());
			errBegin += dist;
		}
	}
};

#endif