making_pairs.py

def create_pairs(x, digit_indices):
    pairs = []
    labels = []

    n = min([len(digit_indices[d]) for d in range(CLASSES_SIZE)]) - 1
    
    for d in range(CLASSES_SIZE):
        for i in range(n):
            z1, z2 = digit_indices[d][i], digit_indices[d][i + 1]
            pairs += [[x[z1], x[z2]]]
            inc = random.randrange(1, CLASSES_SIZE)
            dn = (d + inc) % CLASSES_SIZE
            z1, z2 = digit_indices[d][i], digit_indices[dn][i]
            pairs += [[x[z1], x[z2]]]
            labels += [1, 0]
            
    return np.array(pairs), np.array(labels)


def create_pairs_on_set(images, labels):
    
    digit_indices = [np.where(labels == i)[0] for i in range(CLASSES_SIZE)]
    pairs, y = create_pairs(images, digit_indices)
    y = y.astype('float32')
    
    return pairs, y