def split_aleatoire(data,target,nclass,nTrain):
    indexes = [i for i in range(0,len(data))]
    random.shuffle(indexes)
    train_indexes = indexes[:nTrain]
    test_indexes = indexes[nTrain:]
    train_data = data[train_indexes]
    train_class = target[train_indexes]
    test_data = data[test_indexes]
    test_class = target[test_indexes]
    return train_data, train_class, test_data, test_class