def reconstruct(self, b, X=None):
        """Reconstruct representation of signal b in signal set."""

        if X is None:
            X = self.getcoef()
        Xf = sl.rfftn(X, None, self.cbpdn.cri.axisN)
        slc = (slice(None),)*self.dimN + \
              (slice(self.chncs[b], self.chncs[b+1]),)
        Sf = np.sum(self.cbpdn.Df[slc] * Xf, axis=self.cbpdn.cri.axisM)
        return sl.irfftn(Sf, self.cbpdn.cri.Nv, self.cbpdn.cri.axisN)
Reconstruct representation of signal b in signal set.