//+------------------------------------------------------------------+
//| NeuronConvPool.mqh                                                |
//|                                                                   |
//| CNeuronConv / CNeuronPool - the pure-MQL5 convolution and         |
//| pooling neurons.                                                  |
//|                                                                   |
//| Included from AI\Network.mqh AFTER every class declaration -      |
//| bodies only, no declarations. Relocation is behaviour-neutral by  |
//| construction: nothing here is reachable until Network.mqh ends.   |
//+------------------------------------------------------------------+
#ifndef WARRIOR_AI_IMPL_NEURONCONVPOOL_MQH
#define WARRIOR_AI_IMPL_NEURONCONVPOOL_MQH
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronConv::feedForward(CLayer *prevLayer)
  {
   bool result = false;
//---
   if(CheckPointer(prevLayer) == POINTER_INVALID)
      return result;
//---
   int total = prevLayer.Total() - iWindow + 1;
   CNeuron *temp;
   CConnection *con;
   result = true;
   for(int i = 0; (i < total && result); i += iStep)
     {
      double sum = 0;
      for(int j = 0; (j < iWindow && result); j++)
        {
         temp = prevLayer.At(i + j);
         con = Connections.At(j);
         if(CheckPointer(temp) == POINTER_INVALID || CheckPointer(con) == POINTER_INVALID)
            return false;
         double val = temp.getOutputVal();
         sum += val * con.weight;
        }
      temp = OutputLayer.At(i / iStep);
      if(CheckPointer(temp) == POINTER_INVALID)
         return false;
      temp.setOutputVal(activationFunction(sum));
     }
//---
   return result;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
double CNeuronConv::activationFunction(double x)
  {
   if(x >= 0)
      return x;
   return param * x;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronConv::calcHiddenGradients(CLayer *&nextLayer)
  {
   if(CheckPointer(nextLayer) == POINTER_INVALID || CheckPointer(OutputLayer) == POINTER_INVALID || OutputLayer.Total() <= 0)
      return false;
//---
   gradient = 0;
   int total = OutputLayer.Total();
   CNeuron *temp;
   for(int i = 0; i < total; i++)
     {
      temp = OutputLayer.At(i);
      if(CheckPointer(temp) == POINTER_INVALID)
         return false;
      temp.setGradient(temp.sumDOW(nextLayer)*activationFunctionDerivative(temp.getOutputVal()));
     }
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
double CNeuronConv::activationFunctionDerivative(double x)
  {
   if(x >= 0)
      return 1;
   return param;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronConv::updateInputWeights(CLayer *prevLayer)
  {
   if(CheckPointer(prevLayer) == POINTER_INVALID || CheckPointer(OutputLayer) == POINTER_INVALID)
      return false;
//---
   CConnection *con;
   double lt = eta * sqrt(1 - pow(b2, t)) / (1 - pow(b1, t));
   for(int n = 0; n < iWindow && !IsStopped(); n++)
     {
      con = Connections.At(n);
      if(CheckPointer(con) == POINTER_INVALID)
         continue;
      double delta = 0;
      int total_i = OutputLayer.Total();
      CNeuron *prev, *out;
      for(int i = 0; i < total_i; i++)
        {
         prev = prevLayer.At(n * iStep + i);
         out = OutputLayer.At(total_i - i - 1);
         if(CheckPointer(prev) == POINTER_INVALID || CheckPointer(out) == POINTER_INVALID)
            continue;
         delta += prev.getOutputVal() * out.getGradient();
        }
      if(optimization == SGD)
         con.weight += con.deltaWeight = (delta != 0 ? eta*delta : 0) + (con.deltaWeight != 0 ? alpha*con.deltaWeight : 0);
      else
        {
         con.mt = b1 * con.mt + (1 - b1) * delta;
         con.vt = b2 * con.vt + (1 - b2) * delta * delta + 0.00000001;
         con.deltaWeight = MathMax(-MAX_WEIGHT_DELTA, MathMin(MAX_WEIGHT_DELTA, lt * con.mt / sqrt(con.vt) - lt * WEIGHT_DECAY * con.weight));
         // Sign-agreement gate removed - see CNeuron::updateInputWeights' comment for why.
         con.weight += con.deltaWeight;
        }
      // See CNeuron::updateInputWeights' matching clamp for why this is needed - matches
      // AI\Network.cl's UpdateWeightsConvMomentum/UpdateWeightsConvAdam MAX_WEIGHT clamp.
      con.weight = MathMax(-MAX_WEIGHT, MathMin(MAX_WEIGHT, con.weight));
     }
   if(optimization == ADAM)
      t++;
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronPool::Init(uint numOutputs, uint myIndex, int window, int step, int units_count, ENUM_OPTIMIZATION optimization_type)
  {
   iWindow = window;
   iStep = step;
   //--- LeCun-uniform init, matching CNeuronConvOCL::Init's rationale - fan-in is the conv window size.
   if(!CNeuronBase::Init(window, myIndex, optimization_type, 1.0 / MathSqrt((double)window + 1.0)))
      return false;
   OutputLayer = new CLayer(numOutputs);
   if(CheckPointer(OutputLayer) == POINTER_INVALID)
      return false;
   //--- He-scaled init for the OutputLayer's own dense units - fan-in is this pool/conv unit's own
   //--- sibling count (units_count); no OCL/DLL equivalent exists to mirror since those tiers use flat
   //--- buffers instead of this per-unit object representation, so this follows the same dense rationale
   //--- as CNet::CNet()'s defNeuron case above.
   double outputScale = MathSqrt(2.0 / ((double)units_count + 1.0));
   if(!OutputLayer.Reserve(units_count))
     {
      Print(__FUNCTION__ + ": OutputLayer.Reserve failed (allocation failure?) - neuron would silently end up with 0 outputs");
      return false;
     }
   for(int i = 0; i < units_count; i++)
     {
      if(!OutputLayer.CreateElementScaled(i, outputScale))
         return false;
      OutputLayer.IncreaseTotal();
     }
//---
   if(Type() == defNeuronPool)
     {
      if(CheckPointer(Connections) != POINTER_INVALID)
         Connections.Clear();
     }
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
CNeuronPool::~CNeuronPool(void)
  {
   delete OutputLayer;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronPool::feedForward(CLayer *prevLayer)
  {
   if(CheckPointer(prevLayer) == POINTER_INVALID)
      return false;
//---
   int total = prevLayer.Total() - iWindow + 1;
   CNeuron *temp;
   for(int i = 0; i <= total; i += iStep)
     {
      double sum = 0;
      for(int j = 0; j < iWindow; j++)
        {
         temp = prevLayer.At(i + j);
         if(CheckPointer(temp) == POINTER_INVALID)
            continue;
         sum += temp.getOutputVal();
        }
      temp = OutputLayer.At(i / iStep);
      if(CheckPointer(temp) == POINTER_INVALID)
         return false;
      temp.setOutputVal(sum / iWindow);
     }
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronPool::calcHiddenGradients(CLayer *&nextLayer)
  {
   if(CheckPointer(nextLayer) == POINTER_INVALID || CheckPointer(OutputLayer) == POINTER_INVALID || OutputLayer.Total() <= 0)
      return false;
//---
   gradient = 0;
   int total = OutputLayer.Total();
   CNeuron *temp;
   for(int i = 0; i < total; i++)
     {
      temp = OutputLayer.At(i);
      if(CheckPointer(temp) == POINTER_INVALID)
         return false;
      temp.setGradient(temp.sumDOW(nextLayer));
     }
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronPool::calcInputGradients(CLayer *prevLayer)
  {
   if(CheckPointer(prevLayer) == POINTER_INVALID || CheckPointer(OutputLayer) == POINTER_INVALID  || CheckPointer(prevLayer.At(0)) == POINTER_INVALID)
      return false;
//---
   if(prevLayer.At(0).Type() != defNeuron)
     {
      CNeuronPool *temp = prevLayer.At(m_myIndex);
      if(CheckPointer(temp) == POINTER_INVALID)
         return false;
      prevLayer = temp.getOutputLayer();
      if(CheckPointer(prevLayer) == POINTER_INVALID)
         return false;
     }
//---
   CNeuronBase *prevNeuron, *outputNeuron;
   int total = prevLayer.Total();
   for(int i = 0; i < total; i++)
     {
      prevNeuron = prevLayer.At(i);
      if(CheckPointer(prevNeuron) == POINTER_INVALID)
         continue;
      double prev_gradient = 0;
      int start = i - iWindow + iStep;
      start = (start - start % iStep) / iStep;
      double stop = (i - i % iStep) / iStep + 1;
      for(int out = (int)fmax(0, start); out < (int)fmin(OutputLayer.Total(), stop); out++)
        {
         outputNeuron = OutputLayer.At(out);
         if(CheckPointer(outputNeuron) == POINTER_INVALID)
            continue;
         prev_gradient += outputNeuron.getGradient() / iWindow;
        }
      prevNeuron.setGradient(prev_gradient);
     }
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronPool::calcInputGradients(CNeuronBase *prevNeuron, uint index)
  {
   if(CheckPointer(prevNeuron) == POINTER_INVALID || CheckPointer(OutputLayer) == POINTER_INVALID)
      return false;
//---
   if(prevNeuron.Type() != defNeuron)
     {
      CNeuronPool *temp = prevNeuron;
      return calcInputGradients(temp.getOutputLayer());
     }
//---
   CNeuronBase *outputNeuron;
   double prev_gradient = 0;
   int start = (int)index - iWindow + iStep;
   start = (start - start % iStep) / iStep;
   double stop = (index - index % iStep) / iStep + 1;
   for(int out = (int)fmax(0, start); out < (int)fmin(OutputLayer.Total(), stop); out++)
     {
      outputNeuron = OutputLayer.At(out);
      if(CheckPointer(outputNeuron) == POINTER_INVALID)
         continue;
      prev_gradient += outputNeuron.getGradient() / iWindow;
     }
   prevNeuron.setGradient(prev_gradient);
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronConv::calcInputGradients(CLayer *prevLayer)
  {
   if(CheckPointer(prevLayer) == POINTER_INVALID || CheckPointer(OutputLayer) == POINTER_INVALID)
      return false;
//---
   if(prevLayer.At(0).Type() != defNeuron)
     {
      CNeuronPool *temp = prevLayer.At(m_myIndex);
      if(CheckPointer(temp) == POINTER_INVALID)
         return false;
      prevLayer = temp.getOutputLayer();
      if(CheckPointer(prevLayer) == POINTER_INVALID)
         return false;
     }
//---
   CNeuronBase *prevNeuron, *outputNeuron;
   CConnection *con;
   int total = prevLayer.Total();
   for(int i = 0; i < total; i++)
     {
      prevNeuron = prevLayer.At(i);
      if(CheckPointer(prevNeuron) == POINTER_INVALID)
         continue;
      double prev_gradient = 0;
      int start = i - iWindow + iStep;
      start = (start - start % iStep) / iStep;
      double stop = (i - i % iStep) / iStep + 1;
      for(int out = (int)fmax(0, start); out < (int)fmin(OutputLayer.Total(), stop); out++)
        {
         outputNeuron = OutputLayer.At(out);
         int c = ((int)fmin(OutputLayer.Total(), stop) - out - 1) * iStep + i % iStep;
         con = Connections.At(c);
         if(CheckPointer(outputNeuron) == POINTER_INVALID || CheckPointer(con) == POINTER_INVALID)
            continue;
         prev_gradient += outputNeuron.getGradient() * prevNeuron.activationFunctionDerivative(prevNeuron.getOutputVal()) * con.weight;
        }
      prevNeuron.setGradient(prev_gradient);
     }
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronConv::calcInputGradients(CNeuronBase *prevNeuron, uint index)
  {
   if(CheckPointer(prevNeuron) == POINTER_INVALID || CheckPointer(OutputLayer) == POINTER_INVALID)
      return false;
//---
   if(prevNeuron.Type() != defNeuron)
     {
      CNeuronPool *temp = prevNeuron;
      return calcInputGradients(temp.getOutputLayer());
     }
//---
   CNeuronBase *outputNeuron;
   CConnection *con;
   double prev_gradient = 0;
   int start = (int)index - iWindow + iStep;
   start = (start - start % iStep) / iStep;
   double stop = (index - index % iStep) / iStep + 1;
   for(int out = (int)fmax(0, start); out < (int)fmin(OutputLayer.Total(), stop); out++)
     {
      outputNeuron = OutputLayer.At(out);
      int c = (int)(((int)fmin(OutputLayer.Total(), stop) - out - 1) * iStep + index % iStep);
      con = Connections.At(c);
      if(CheckPointer(outputNeuron) == POINTER_INVALID || CheckPointer(con) == POINTER_INVALID)
         continue;
      prev_gradient += outputNeuron.getGradient() * activationFunctionDerivative(outputNeuron.getOutputVal()) * con.weight;
     }
   prevNeuron.setGradient(prev_gradient);
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronPool::Save(const int file_handle)
  {
   if(!CNeuronBase::Save(file_handle) || !OutputLayer.Save(file_handle))
      return false;
   if(FileWriteInteger(file_handle, iWindow, INT_VALUE) < INT_VALUE)
      return false;
   if(FileWriteInteger(file_handle, iStep, INT_VALUE) < INT_VALUE)
      return false;
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronPool::Load(const int file_handle)
  {
   if(!CNeuronBase::Load(file_handle) || !OutputLayer.Load(file_handle))
      return false;
   iWindow = FileReadInteger(file_handle, INT_VALUE);
   iStep = FileReadInteger(file_handle, INT_VALUE);
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronConv::Save(const int file_handle)
  {
   if(!CNeuronPool::Save(file_handle))
      return false;
   if(FileWriteDouble(file_handle, param) < 8)
      return false;
//---
   return true;
  }
//+------------------------------------------------------------------+
//|                                                                   |
//+------------------------------------------------------------------+
bool CNeuronConv::Load(const int file_handle)
  {
   if(!CNeuronPool::Load(file_handle))
      return false;
   param = FileReadDouble(file_handle);
//---
   return true;
  }
#endif