Generic Neural Network

nn.php

<?php
/******************* CONFIG *******************/
$config_nn_layout = [2, 3, 2, 1];
$config_nn_step = 7;

/******************** MAIN ********************/
$neurons = nn_init_neurons($config_nn_layout);
$weights = nn_init_weights($config_nn_layout);

while (true) {
    $neurons = nn_init_neurons($config_nn_layout);
    $fp = fopen('php://stdin', 'r');
    echo 'Input A: ';
    $neurons['0:0'] = trim(fgets($fp));
    echo 'Input B: ';
    $neurons['0:1'] = trim(fgets($fp));
    $output = nn_compute($neurons, $weights, $config_nn_layout);
    echo 'Output: '.$output[0]."\n";
    echo 'Is the output correct? [y/n] ';
    $correct = trim(fgets($fp)) == 'y';
    $weights = nn_adjust_weights($neurons, $weights, $config_nn_step, $config_nn_layout);
    echo '----------------'."\n";
}

/****************** FUNCTIONS *****************/
function nn_adjust_weights($neurons, $weights, $step, Array $nbs)
{
    //TODO
}

function nn_compute($neurons, $weights, Array $nbs)
{
    $layer = 0;

    foreach ($nbs as $k => $nb) {
        if ($k) {
            echo 'Processing layer '.$layer.'...'."\n";
            for ($i = 0; $i < $nb; $i++) {
                echo '-> '.$i."\n";
                $sum = 0;
                for ($j = 0; $j < $nbs[$k-1]; $j++) {
                    $w = $weights[($layer-1).':'.$j.';'.$layer.':'.$i];
                    $n = $neurons[($layer-1).':'.$j];
                    echo 'Layer '.($layer-1).' neuron '.$j.' has value '.$n.' and weight '.$w."\n";
                    if ($n) {
                        $sum += $w;
                    }
                }
                echo 'Calculated sum is: '.$sum."\n";
                if ($sum >= 50) {
                    $neurons[$layer.':'.$i] = 1;
                }
            }
        }
        $layer++;
    }

    $output = [];
    for ($i = 0; $i < $nb; $i++) {
        $output[] = $neurons[$k.':'.$i];
    }

    return $output;
}

function nn_init_weights(Array $nbs)
{
    $weights = [];
    $layer = 0;

    foreach ($nbs as $k => $nb) {
        for ($i = 0; $i < $nb; $i++) {
            if (isset($nbs[$k+1])) {
                for ($j = 0; $j < $nbs[$k+1]; $j++) {
                    $weights[$layer.':'.$i.';'.($layer+1).':'.$j] = rand(0, 100);
                }
            }
        }
        $layer++;
    }

    return $weights;
}

function nn_init_neurons(Array $nbs)
{
    $neurons = [];
    $layer = 0;

    foreach ($nbs as $nb) {
        for ($i = 0; $i < $nb; $i++) {
            $neurons[$layer.':'.$i] = 0;
        }
        $layer++;
    }

    return $neurons;
}