pitch_features.py 文件源码

def to_intervals(X):

    def _roll_rows(x):
        """ Circularly shift ('roll') rows i in array by -i, recursively.
        If 2d-array: circularly shift each row i to the left, i times so that
            X(i, j-i) = X(i, j)
        If 3d-array (or 4d, 5d..):
            X(i, j-i, k-j) = X(i, j, k)
        """
        if len(x.shape) > 2:
            x = np.array([_roll_rows(xi) for xi in x])
        elif len(x.shape) == 1:
            raise ValueError('Method requires nd-array with n >= 2.')
        x_rolled = np.array([np.roll(xi, -i, axis=0) for i, xi in enumerate(x)])
        return x_rolled

    X_rolled = _roll_rows(X)

    X_inv = np.sum(X_rolled, axis=0)

    return X_inv


## ------------------------- feature alignment