Ejemplo n.º 1
0
    def nlog_density(self, target, source, log_weights, scales, probas=None):
        """Negative log-likelihood of the proposal generated by the source onto the target."""

        x_i = LazyTensor(target[:, None, :])  # (N,1,D)
        y_j = LazyTensor(self.means[None, :, :])  # (1,M,D)
        s_j = self.covariances_inv  # (M, D, D)
        s_j = LazyTensor(s_j.view(s_j.shape[0], -1)[None, :, :])  # (1, M, D*D)
        D_ij = (x_i - y_j) | s_j.matvecmult(x_i - y_j)  # (N,M,1)

        det_j = LazyTensor(self.log_det_cov_half[None, :, None])

        logK_ij = (-D_ij / 2 - (self.D / 2) * float(np.log(2 * np.pi)) - det_j)

        log_weights = self.weights.log()
        logW_j = LazyTensor(log_weights[None, :, None])
        logK_ij = logK_ij + logW_j

        logdensities_i = logK_ij.logsumexp(dim=1).reshape(-1)  # (N,)
        return -logdensities_i
Ejemplo n.º 2
0
    def nlog_density(self, target, source, log_weights, scales, probas=None):
        """Negative log-likelihood of the proposal generated by the source onto the target."""

        if self.adaptive:

            x_i = LazyTensor(target[:, None, :])  # (N,1,D)
            y_j = LazyTensor(source[None, :, :])  # (1,M,D)
            s_j = self.covariances_inv  # (M, D, D)
            s_j = LazyTensor(s_j.view(s_j.shape[0],
                                      -1)[None, :, :])  # (1, M, D*D)
            D_ij = (x_i - y_j) | s_j.matvecmult(x_i - y_j)  # (N,M,1)

            det_j = LazyTensor(self.log_det_cov_half[None, :, None])

            logK_ij = (-D_ij / 2 - (self.D / 2) * float(np.log(2 * np.pi)) -
                       det_j)

        else:
            D_ij = squared_distances(target, source)
            logK_ij = (-D_ij / (2 * scales**2) -
                       (self.D / 2) * float(np.log(2 * np.pi)) -
                       self.D * scales.log())

        if log_weights is None:
            logK_ij = logK_ij - float(np.log(len(source)))
        else:
            logW_j = LazyTensor(log_weights[None, :, None])
            logK_ij = logK_ij + logW_j

        logdensities_i = logK_ij.logsumexp(dim=1).view(-1)  # (N,)

        if probas is None:
            return -logdensities_i
        else:
            return -(logdensities_i.view(-1, len(probas)) +
                     probas.log()[None, :]).logsumexp(dim=1).view(-1)
    def routine(self,
                α,
                x,
                β,
                y,
                class_xy=None,
                class_yx=None,
                class_xx=None,
                class_yy=None,
                mask_diagonal=False,
                **kwargs):

        N, D = x.shape
        M, _ = y.shape

        if self.debias:
            C_xx = self.calculate_cost(x, x.detach(), class_xx)
            C_yy = self.calculate_cost(y, y.detach(), class_yy)

        else:
            C_xx, C_yy = Non

        C_xy = self.calculate_cost(x, y.detach(), class_xy)
        C_yx = self.calculate_cost(y, x.detach(), class_yx)

        softmin = partial(self.softmin_online,
                          log_conv=self.logconv(C_xy, dtype=str(x.dtype)[6:]))

        diameter, ε, ε_s, ρ = scaling_parameters(x, y, self.p, self.blur,
                                                 self.reach, self.diameter,
                                                 self.scaling)

        a_x, b_y, a_y, b_x = sinkhorn_loop(softmin,
                                           log_weights(α),
                                           log_weights(β),
                                           C_xx,
                                           C_yy,
                                           C_xy,
                                           C_yx,
                                           ε_s,
                                           ρ,
                                           debias=self.debias)

        F, G = sinkhorn_cost(ε,
                             ρ,
                             α,
                             β,
                             a_x,
                             b_y,
                             a_y,
                             b_x,
                             debias=self.debias,
                             potentials=True)

        a_i = α.view(-1, 1)
        b_j = β.view(1, -1)
        F_i, G_j = F.view(-1, 1), G.view(1, -1)

        cost = (F_i + G_j).mean()

        # coupling calculation
        F_i = LazyTensor(F_i.view(-1, 1, 1))
        G_j = LazyTensor(G_j.view(1, -1, 1))
        a_i = LazyTensor(a_i.view(-1, 1, 1))
        b_j = LazyTensor(b_j.view(1, -1, 1))

        if len(C_xy) == 2:
            x, y = C_xy
            C_ij = self.cost(x, y)
        else:
            x, y, Z, L = C_xy
            C_ij = self.cost(x, y, class_values=[Z, L])

        coupling = ((F_i + G_j - C_ij) / self.eps).exp() * (a_i * b_j)

        return cost, coupling, C_ij, [F_i, G_j, a_i, b_j]