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C/C++ Perceptron
Introduction
This project was created in order to enable Perceptron creation and training API for C programmers.
This library enables training the perceptron step by step and enables to check its state at each step.

API & Usage Example

The text printed to the shell

Results for 'OR' perceptron, BEFORE training:
Input: (0,0). Result: 0
Input: (0,1). Result: 0
Input: (1,0). Result: 0
Input: (1,1). Result: 0
Results for 'AND' perceptron, BEFORE training:
Input: (0,0). Result: 1
Input: (0,1). Result: 0
Input: (1,0). Result: 1
Input: (1,1). Result: 0
Results for 'OR' perceptron, AFTER training:
Input: (0,0). Result: 0
Input: (0,1). Result: 1
Input: (1,0). Result: 1
Input: (1,1). Result: 1
Results for 'AND' perceptron, AFTER training:
Input: (0,0). Result: 0
Input: (0,1). Result: 0
Input: (1,0). Result: 0
Input: (1,1). Result: 1

The code

#include <stdio.h>

#include "perceptron.h"

int main() {
    // Constants
    const int TRAINING_ITERATIONS = 16;
    const int NUM_OF_INPUTS = 2;
    const double TRAINING_RATE = 0.2;

    const double ZERO_ZERO[] = {0, 0};
    const double ZERO_ONE[]  = {0, 1};
    const double ONE_ZERO[]  = {1, 0};
    const double ONE_ONE[]   = {1, 1};

    int i;
    // Creating Perceptron instances
    Perceptron *pAND = Perceptron_new(NUM_OF_INPUTS, TRAINING_RATE);
    Perceptron *pOR  = Perceptron_new(NUM_OF_INPUTS, TRAINING_RATE);

    // Printing the results of the randomly generated perceptrons (BEFORE TRAINING)
    printf("Results for 'OR' perceptron, BEFORE training:\n");
    printf("Input: (0,0). Result: %d\n", Perceptron_getResult(pOR, ZERO_ZERO));
    printf("Input: (0,1). Result: %d\n", Perceptron_getResult(pOR, ZERO_ONE));
    printf("Input: (1,0). Result: %d\n", Perceptron_getResult(pOR, ONE_ZERO));
    printf("Input: (1,1). Result: %d\n", Perceptron_getResult(pOR, ONE_ONE));

    printf("Results for 'AND' perceptron, BEFORE training:\n");
    printf("Input: (0,0). Result: %d\n", Perceptron_getResult(pAND, ZERO_ZERO));
    printf("Input: (0,1). Result: %d\n", Perceptron_getResult(pAND, ZERO_ONE));
    printf("Input: (1,0). Result: %d\n", Perceptron_getResult(pAND, ONE_ZERO));
    printf("Input: (1,1). Result: %d\n", Perceptron_getResult(pAND, ONE_ONE));

    // Training each of the perceptrons
    for (i = 0 ; i < TRAINING_ITERATIONS ; i++) {
        Perceptron_train(pAND, ZERO_ZERO, 0);
        Perceptron_train(pAND, ZERO_ONE,  0);
        Perceptron_train(pAND, ONE_ZERO,  0);
        Perceptron_train(pAND, ONE_ONE,   1);

        Perceptron_train(pOR, ZERO_ZERO,  0);
        Perceptron_train(pOR, ZERO_ONE,   1);
        Perceptron_train(pOR, ONE_ZERO,   1);
        Perceptron_train(pOR, ONE_ONE,    1);
    }

    // Printing the results of the trained perceptrons (AFTER TRAINING)
    printf("Results for 'OR' perceptron, AFTER training:\n");
    printf("Input: (0,0). Result: %d\n", Perceptron_getResult(pOR, ZERO_ZERO));
    printf("Input: (0,1). Result: %d\n", Perceptron_getResult(pOR, ZERO_ONE));
    printf("Input: (1,0). Result: %d\n", Perceptron_getResult(pOR, ONE_ZERO));
    printf("Input: (1,1). Result: %d\n", Perceptron_getResult(pOR, ONE_ONE));

    printf("Results for 'AND' perceptron, AFTER training:\n");
    printf("Input: (0,0). Result: %d\n", Perceptron_getResult(pAND, ZERO_ZERO));
    printf("Input: (0,1). Result: %d\n", Perceptron_getResult(pAND, ZERO_ONE));
    printf("Input: (1,0). Result: %d\n", Perceptron_getResult(pAND, ONE_ZERO));
    printf("Input: (1,1). Result: %d\n", Perceptron_getResult(pAND, ONE_ONE));

    return 0;
}

API

// Create a new perceptron with specified size of input-vector and a specified training rate
// The size of the input vector will be changed to "1" in case that 0 or negative number is passed
Perceptron *Perceptron_new(unsigned numOfInputs, double trainingRate);

// Get the sum of (input(0) * weight(0) + input(1) * weight(1) + ... + input(n) * weight(n))
double Perceptron_getValue(const Perceptron *perceptron, const double inputs[]);

// Change the training rate
void Perceptron_setTrainingRate(Perceptron *perceptron, double trainingRate);

// Train perceptron according to an input vector and its expected result (result should be 0 or 1)
void Perceptron_train(Perceptron *perceptron, const double inputs[], int expectedResult);

// Get the result for an input vector (result is 0 or 1)
// Returns 1 in case that **Perceptron_getValue(perceptron, inputs)** is higher or equals to the thresholds. Returns 0 otherwise
int Perceptron_getResult(const Perceptron *perceptron, const double inputs[]);

// Get the weight at a specific index in the weights vector
double Perceptron_getWeightAt(const Perceptron *perceptron, unsigned index);

// Get the weights vector
const double *Perceptron_getWeights(const Perceptron *perceptron);

// Get the number of the inputs in the perceptron
unsigned Perceptron_getNumOfInputs(const Perceptron *perceptron);

// Get the threshold
double Perceptron_getThreshold(const Perceptron *perceptron);

// Get the training rate
double Perceptron_getTrainingRate(const Perceptron *perceptron);

// Change the weight at a specific index
void Perceptron_setWeightAt(Perceptron *perceptron, unsigned index, double weight);

// Change the weights vector (copying, not replacing pointers)
void Perceptron_setWeights(Perceptron *perceptron, const double *weights);

// Change the threshold
void Perceptron_setThreshold(Perceptron *perceptron, double threshold);