    def initial_state(self):
        """Obtain an initial CTC state

        :return: CTC state
        """
        # initial CTC state is made of a frame x 2 tensor that corresponds to
        # r_t^n(<sos>) and r_t^b(<sos>), where 0 and 1 of axis=1 represent
        # superscripts n and b (non-blank and blank), respectively.
        r = self.xp.full((self.input_length, 2), self.logzero, dtype=np.float32)
        r[0, 1] = self.x[0, self.blank]
        for i in six.moves.range(1, self.input_length):
            r[i, 1] = r[i - 1, 1] + self.x[i, self.blank]
        return r
Obtain an initial CTC state

:return: CTC state
modules/wenet_extractor/paraformer/search/ctc_prefix_score.py