replay.py 文件源码

def shuffle_transmat(transmat):
    """Shuffle transition probability matrix within each row, leaving self transitions in tact.

    It is assumed that the transmat is stochastic-row-wise, meaning that A_{ij} = Pr(S_{t+1}=j|S_t=i).

    Parameters
    ----------
    transmat : array of size (n_states, n_states)
        Transition probability matrix, where A_{ij} = Pr(S_{t+1}=j|S_t=i).

    Returns
    -------
    shuffled : array of size (n_states, n_states)
        Shuffled transition probability matrix.
    """
    shuffled = transmat.copy()

    nrows, ncols = transmat.shape
    for rowidx in range(nrows):
        all_but_diagonal = np.append(np.arange(rowidx), np.arange(rowidx+1, ncols))
        shuffle_idx = np.random.permutation(all_but_diagonal)
        shuffle_idx = np.insert(shuffle_idx, rowidx, rowidx)
        shuffled[rowidx,:] = shuffled[rowidx, shuffle_idx]

    return shuffled