Function calibrate_full_matrix 

pub fn calibrate_full_matrix<F>(
    nr_cpus: usize,
    config: &EtdConfig,
    progress_callback: F,
) -> Vec<Vec<f64>>
where
    F: FnMut(usize, usize, bool),

Perform full topology calibration. Returns matrix[i][j] = latency from CPU i to CPU j.