bool ReadFile(float* M, const char* file_name) {
    std::ifstream fin(file_name);
    if (!fin) {
        std::cerr << "Unable to open file " << file_name << std::endl;
        return false;
    }
    int i = 0;
    for(;fin>>M[i] && i<NUM_ELEMENTS; ++i);
    return i == NUM_ELEMENTS;
}