#include <math.h>
// global variables
const int R = 3;
const int C = 2;
const int N = 4;

const int ndigits = 4;  //number of digits of precision in printed values

float node[R] = {};
float outputs[C] = {};

float errorH[R] = {};
float errorO[C] = {};

int Inputs[N] = { 1, 0, 1, 0 };

float WeightH[R][N] = {
  { 0.1, 0.9, 0.5, 0.25 },
  { -0.2, -0.1, 0.8, -0.45 },
  { 0.7, -0.6, -0.3, 0.4 }
};

double WeightO[C][R] = {
  { 0.75, -0.4, -0.5 },
  { -0.9, 0.2, 0.3 }
};

int Target[C] = { 1, 0 };

void setup() {
  Serial.begin(19200);

  // Hidden layer
  for (int r = 0; r < R; r++) {
    for (int n = 0; n < N; n++) {
      node[r] = node[r] + (Inputs[n] * WeightH[r][n]);
    }
  }
  // Sigmoid function
  for (int r = 0; r < R; r++) {
    node[r] = 1 / (1 + exp(-node[r]));
  }

  // Output layer
  for (int n = 0; n < 2; n++) {//why not N
    for (int c = 0; c < 2; c++) { //why not C
      outputs[n] = outputs[n] + (node[c] * WeightO[n][c]);
    }
  }
  // Sigmoid function
  for (int c = 0; c < 2; c++) {  //why not C
    outputs[c] = 1 / (1 + exp(-outputs[c]));
  }

  // Reverse Pass //
  // Errors

  for (int c = 0; c < 2; c++) {  //why not C
    errorO[c] = outputs[c] * (1 - outputs[c]) * (Target[c] - outputs[c]);
  }

  // New Weights

  for (int n = 0; n < 2; n++) { //why not N
    for (int c = 0; c < 3; c++) { //why not C
      WeightO[n][c] = WeightO[n][c] + (errorO[n] * node[c]);
    }
  }

  // Hidden Errors

  for (int r = 0; r < 3; r++) {  //why not R
    int n = 0;
    errorH[r] = node[r] * (1 - node[r]) * ((WeightO[r][n] * errorO[n]) + (WeightO[r][n + 1] * errorO[n + 1]));
  }

  // New Hidden Layer Weights

  for (int n = 0; n < 3; n++) { //why not N
    for (int c = 0; c < 4; c++) {//why not C
      WeightH[n][c] = WeightH[n][c] + (errorH[n] * Inputs[c]);
    }
  }
  Serial.println();
  Serial.println("Output Errors:");
  Serial.println(errorO[0], ndigits);
  Serial.println(errorO[1], ndigits);
  Serial.println("Output Weights:");
  Serial.println(WeightO[0][0], ndigits);
  Serial.println(WeightO[0][1], ndigits);
  Serial.println(WeightO[0][2], ndigits);
  Serial.println(WeightO[1][0], ndigits);
  Serial.println(WeightO[1][1], ndigits);
  Serial.println(WeightO[1][2], ndigits);
  Serial.println("Hidden Layer Errors:");
  Serial.println(errorH[0], ndigits);
  Serial.println(errorH[1], ndigits);
  Serial.println(errorH[2], ndigits);
  Serial.println("Hidden Layer Weights:");
  Serial.println(WeightH[0][0], ndigits);
  Serial.println(WeightH[0][1], ndigits);
  Serial.println(WeightH[0][2], ndigits);
  Serial.println(WeightH[0][3], ndigits);
  Serial.println(WeightH[1][0], ndigits);
  Serial.println(WeightH[1][1], ndigits);
  Serial.println(WeightH[1][2], ndigits);
  Serial.println(WeightH[1][3], ndigits);
  Serial.println(WeightH[2][0], ndigits);
  Serial.println(WeightH[2][1], ndigits);
  Serial.println(WeightH[2][2], ndigits);
  Serial.println(WeightH[2][3], ndigits);
}

void loop() {}