Interpolation matrix of numbers with mean values

output

$ php scale.php

[5 x 5]
13.00	11.00	13.00	15.00	10.00
12.00	10.00	15.00	11.00	13.00
10.00	15.00	10.00	12.00	14.00
15.00	11.00	13.00	11.00	14.00
15.00	13.00	15.00	12.00	 0.00


[9 x 9]
13.00	12.00	11.00	12.00	13.00	14.00	15.00	12.50	10.00
12.50	11.50	10.50	12.25	14.00	13.50	13.00	12.25	11.50
12.00	11.00	10.00	12.50	15.00	13.00	11.00	12.00	13.00
11.00	11.75	12.50	12.50	12.50	12.00	11.50	12.50	13.50
10.00	12.50	15.00	12.50	10.00	11.00	12.00	13.00	14.00
12.50	12.75	13.00	12.25	11.50	11.50	11.50	12.75	14.00
15.00	13.00	11.00	12.00	13.00	12.00	11.00	12.50	14.00
15.00	13.50	12.00	13.00	14.00	12.75	11.50	 9.25	 7.00
15.00	14.00	13.00	14.00	15.00	13.50	12.00	 6.00	 0.00


[17 x 17]
13.00	12.50	12.00	11.50	11.00	11.50	12.00	12.50	13.00	13.50	14.00	14.50	15.00	13.75	12.50	11.25	10.00
12.75	12.25	11.75	11.25	10.75	11.44	12.12	12.81	13.50	13.62	13.75	13.88	14.00	13.19	12.38	11.56	10.75
12.50	12.00	11.50	11.00	10.50	11.38	12.25	13.12	14.00	13.75	13.50	13.25	13.00	12.62	12.25	11.88	11.50
12.25	11.75	11.25	10.75	10.25	11.31	12.38	13.44	14.50	13.88	13.25	12.62	12.00	12.06	12.12	12.19	12.25
12.00	11.50	11.00	10.50	10.00	11.25	12.50	13.75	15.00	14.00	13.00	12.00	11.00	11.50	12.00	12.50	13.00
11.50	11.44	11.38	11.31	11.25	11.88	12.50	13.12	13.75	13.12	12.50	11.88	11.25	11.75	12.25	12.75	13.25
11.00	11.38	11.75	12.12	12.50	12.50	12.50	12.50	12.50	12.25	12.00	11.75	11.50	12.00	12.50	13.00	13.50
10.50	11.31	12.12	12.94	13.75	13.12	12.50	11.88	11.25	11.38	11.50	11.62	11.75	12.25	12.75	13.25	13.75
10.00	11.25	12.50	13.75	15.00	13.75	12.50	11.25	10.00	10.50	11.00	11.50	12.00	12.50	13.00	13.50	14.00
11.25	11.94	12.62	13.31	14.00	13.19	12.38	11.56	10.75	11.00	11.25	11.50	11.75	12.31	12.88	13.44	14.00
12.50	12.62	12.75	12.88	13.00	12.62	12.25	11.88	11.50	11.50	11.50	11.50	11.50	12.12	12.75	13.38	14.00
13.75	13.31	12.88	12.44	12.00	12.06	12.12	12.19	12.25	12.00	11.75	11.50	11.25	11.94	12.62	13.31	14.00
15.00	14.00	13.00	12.00	11.00	11.50	12.00	12.50	13.00	12.50	12.00	11.50	11.00	11.75	12.50	13.25	14.00
15.00	14.12	13.25	12.38	11.50	12.00	12.50	13.00	13.50	12.94	12.38	11.81	11.25	11.06	10.88	10.69	10.50
15.00	14.25	13.50	12.75	12.00	12.50	13.00	13.50	14.00	13.38	12.75	12.12	11.50	10.38	 9.25	 8.12	 7.00
15.00	14.38	13.75	13.12	12.50	13.00	13.50	14.00	14.50	13.81	13.12	12.44	11.75	 9.69	 7.62	 5.56	 3.50
15.00	14.50	14.00	13.50	13.00	13.50	14.00	14.50	15.00	14.25	13.50	12.75	12.00	 9.00	 6.00	 3.00	 0.00

scale.php

<?php

function display($data, array $size) {
    print PHP_EOL . '[' . $size[0] . ' x ' . $size[1] . ']' . PHP_EOL;
    $idx = 0;
    for ($i = 0; $i < $size[0]; $i++) {
        for ($j = 0; $j < $size[1]; $j++) {
            printf("%5.2f\t", $data[$idx]);
            $idx++;
        }
        print PHP_EOL;
    }
    print PHP_EOL;
}

function create_data(array $size = [2,2], $min = 0, $max = 1, $rand_cut = true) {
    $cut = (($rand_cut) ? rand(1, $size[1] / 2) : 0);
    $plain_size = $size[0] * $size[1] - $cut;
    $data = [];
    for ($i = 0; $i < $plain_size; $i++) {
        $data[$i] = rand(min([$min, $max]), max([$min, $max]));
    }
    for ($j = $i; $j < $plain_size + $cut; $j++) {
        $data[$j] = 0;
    }
    return [$data, $size];
}

function avg(array $els) {
    if (count($els) == 0) return 0;
    return array_sum($els) / count($els);
}

function array_matrix($data, array $size) {
    $matrix = [];
    $idx = 0;
    for ($row = 0; $row < $size[0]; $row++) {
        for ($column = 0; $column < $size[1]; $column++) {
            $matrix[$row][$column] = $data[$idx];
            $idx++;
        }
    }
    return $matrix;
}

function array_flatten($array, $return) {
    for ($i = 0; $i < count($array); $i++) {
        if (is_array($array[$i])) {
            $return = array_flatten($array[$i], $return);
        } else {
            if (isset($array[$i])) {
                $return[] = $array[$i];
            }
        }
    }
    return $return;
}

function scale($data, array $size) {
    $matrix = array_matrix($data, $size);
    $new_matrix = [];
    for ($row = 0; $row < $size[0]; $row++) {
        for ($column = 0; $column < $size[1]; $column++) {
            if ($column == 0) {
                $new_matrix[$row][] = $matrix[$row][$column];
                continue;
            }
            $new_matrix[$row][] = avg([$matrix[$row][$column - 1], $matrix[$row][$column]]);
            $new_matrix[$row][] = $matrix[$row][$column];
        }
    }
    $matrix = $new_matrix;
    $new_matrix = [];
    for ($row = 0; $row < $size[0]; $row++) {
        if ($row == 0) {
            $new_matrix[] = $matrix[0];
            continue;
        }
        $new_row = [];
        for ($column = 0; $column < count($matrix[$row]); $column++) {
            $new_row[] = avg([$matrix[$row - 1][$column], $matrix[$row][$column]]);
        }
        $new_matrix[] = $new_row;
        $new_matrix[] = $matrix[$row];
    }
    return [array_flatten($new_matrix, []), [count($new_matrix), count($new_matrix[0])]];
}

$data = create_data([5,5], 10, 15);
display($data[0], $data[1]);

$data = scale($data[0], $data[1]);
display($data[0], $data[1]);

$data = scale($data[0], $data[1]);
display($data[0], $data[1]);