def _log_prob(self, inputs, context): if inputs.shape[1:] != self._shape: raise ValueError('Expected input of shape {}, got {}'.format( self._shape, inputs.shape[1:])) # Compute parameters. means, log_stds = self._compute_params(context) assert means.shape == inputs.shape and log_stds.shape == inputs.shape # Compute log prob. norm_inputs = (inputs - means) * torch.exp(-log_stds) log_prob = -0.5 * utils.sum_except_batch(norm_inputs ** 2, num_batch_dims=1) log_prob -= utils.sum_except_batch(log_stds, num_batch_dims=1) log_prob -= self._log_z return log_prob
def inverse(self, inputs, context=None): if torch.min(inputs) <= -1 or torch.max(inputs) >= 1: raise transforms.InputOutsideDomain() outputs = 0.5 * torch.log((1 + inputs) / (1 - inputs)) logabsdet = -torch.log(1 - inputs**2) logabsdet = utils.sum_except_batch(logabsdet, num_batch_dims=1) return outputs, logabsdet
def _spline(self, inputs, inverse=False): batch_size = inputs.shape[0] unnormalized_widths = _share_across_batch(self.unnormalized_widths, batch_size) unnormalized_heights = _share_across_batch(self.unnormalized_heights, batch_size) unnormalized_derivatives = _share_across_batch( self.unnormalized_derivatives, batch_size) if self.tails is None: spline_fn = splines.rational_quadratic_spline spline_kwargs = {} else: spline_fn = splines.unconstrained_rational_quadratic_spline spline_kwargs = { 'tails': self.tails, 'tail_bound': self.tail_bound } outputs, logabsdet = spline_fn( inputs=inputs, unnormalized_widths=unnormalized_widths, unnormalized_heights=unnormalized_heights, unnormalized_derivatives=unnormalized_derivatives, inverse=inverse, min_bin_width=self.min_bin_width, min_bin_height=self.min_bin_height, min_derivative=self.min_derivative, **spline_kwargs) return outputs, utils.sum_except_batch(logabsdet)
def forward(self, inputs, context=None): inputs = self.temperature * inputs outputs = torch.sigmoid(inputs) logabsdet = utils.sum_except_batch( torch.log(self.temperature) - F.softplus(-inputs) - F.softplus(inputs)) return outputs, logabsdet
def inverse(self, inputs, context=None): outputs = F.leaky_relu(inputs, negative_slope=(1 / self.negative_slope)) mask = (inputs < 0).type(torch.Tensor) logabsdet = -self.log_negative_slope * mask logabsdet = utils.sum_except_batch(logabsdet, num_batch_dims=1) return outputs, logabsdet
def _log_prob(self, inputs, context): # Note: the context is ignored. if inputs.shape[1:] != self._shape: raise ValueError('Expected input of shape {}, got {}'.format( self._shape, inputs.shape[1:])) neg_energy = -0.5 * utils.sum_except_batch(inputs ** 2, num_batch_dims=1) return neg_energy - self._log_z
def inverse(self, inputs, context=None): if torch.min(inputs) < 0 or torch.max(inputs) > 1: raise transforms.InputOutsideDomain() outputs = torch.tan(np.pi * (inputs - 0.5)) logabsdet = -utils.sum_except_batch(-np.log(np.pi) - torch.log(1 + outputs**2)) return outputs, logabsdet
def _lu_forward_inverse(self, inputs, inverse=False): b, c, h, w = inputs.shape inputs = inputs.permute(0, 2, 3, 1).reshape(b*h*w, c) if inverse: outputs, logabsdet = super().inverse(inputs) else: outputs, logabsdet = super().forward(inputs) outputs = outputs.reshape(b, h, w, c).permute(0, 3, 1, 2) logabsdet = logabsdet.reshape(b, h, w) return outputs, utils.sum_except_batch(logabsdet)
def _coupling_transform(self, inputs, transform_params, inverse=False): if inputs.dim() == 4: b, c, h, w = inputs.shape # For images, reshape transform_params from Bx(C*?)xHxW to BxCxHxWx? transform_params = transform_params.reshape(b, c, -1, h, w).permute(0, 1, 3, 4, 2) elif inputs.dim() == 2: b, d = inputs.shape # For 2D data, reshape transform_params from Bx(D*?) to BxDx? transform_params = transform_params.reshape(b, d, -1) outputs, logabsdet = self._piecewise_cdf(inputs, transform_params, inverse) return outputs, utils.sum_except_batch(logabsdet)
def inverse(self, inputs, context=None): if torch.min(inputs) < 0 or torch.max(inputs) > 1: raise transforms.InputOutsideDomain() inputs = torch.clamp(inputs, self.eps, 1 - self.eps) outputs = (1 / self.temperature) * (torch.log(inputs) - torch.log1p(-inputs)) logabsdet = -utils.sum_except_batch( torch.log(self.temperature) - F.softplus(-self.temperature * outputs) - F.softplus(self.temperature * outputs)) return outputs, logabsdet
def _log_prob(self, inputs, context): if inputs.shape[1:] != self._shape: raise ValueError('Expected input of shape {}, got {}'.format( self._shape, inputs.shape[1:])) # Compute parameters. logits = self._compute_params(context) assert logits.shape == inputs.shape # Compute log prob. log_prob = -inputs * F.softplus(-logits) - ( 1.0 - inputs) * F.softplus(logits) log_prob = utils.sum_except_batch(log_prob, num_batch_dims=1) return log_prob
def forward(self, inputs, context=None): mask_right = (inputs > self.cut_point) mask_left = (inputs < -self.cut_point) mask_middle = ~(mask_right | mask_left) outputs = torch.zeros_like(inputs) outputs[mask_middle] = torch.tanh(inputs[mask_middle]) outputs[mask_right] = self.alpha * torch.log( self.beta * inputs[mask_right]) outputs[mask_left] = self.alpha * -torch.log( -self.beta * inputs[mask_left]) logabsdet = torch.zeros_like(inputs) logabsdet[mask_middle] = torch.log(1 - outputs[mask_middle]**2) logabsdet[mask_right] = torch.log(self.alpha / inputs[mask_right]) logabsdet[mask_left] = torch.log(-self.alpha / inputs[mask_left]) logabsdet = utils.sum_except_batch(logabsdet, num_batch_dims=1) return outputs, logabsdet
def _spline(self, inputs, inverse=False): batch_size = inputs.shape[0] unnormalized_pdf = _share_across_batch(self.unnormalized_pdf, batch_size) if self.tails is None: outputs, logabsdet = splines.linear_spline( inputs=inputs, unnormalized_pdf=unnormalized_pdf, inverse=inverse) else: outputs, logabsdet = splines.unconstrained_linear_spline( inputs=inputs, unnormalized_pdf=unnormalized_pdf, inverse=inverse, tails=self.tails, tail_bound=self.tail_bound) return outputs, utils.sum_except_batch(logabsdet)
def inverse(self, inputs, context=None): mask_right = (inputs > self.inv_cut_point) mask_left = (inputs < -self.inv_cut_point) mask_middle = ~(mask_right | mask_left) outputs = torch.zeros_like(inputs) outputs[mask_middle] = 0.5 * torch.log( (1 + inputs[mask_middle]) / (1 - inputs[mask_middle])) outputs[mask_right] = torch.exp( inputs[mask_right] / self.alpha) / self.beta outputs[mask_left] = -torch.exp( -inputs[mask_left] / self.alpha) / self.beta logabsdet = torch.zeros_like(inputs) logabsdet[mask_middle] = -torch.log(1 - inputs[mask_middle]**2) logabsdet[mask_right] = -np.log( self.alpha * self.beta) + inputs[mask_right] / self.alpha logabsdet[mask_left] = -np.log( self.alpha * self.beta) - inputs[mask_left] / self.alpha logabsdet = utils.sum_except_batch(logabsdet, num_batch_dims=1) return outputs, logabsdet
def _coupling_transform_forward(self, inputs, transform_params): scale, shift = self._scale_and_shift(transform_params) log_scale = torch.log(scale) outputs = inputs * scale + shift logabsdet = utils.sum_except_batch(log_scale, num_batch_dims=1) return outputs, logabsdet
def forward(self, inputs, context=None): outputs = torch.tanh(inputs) logabsdet = torch.log(1 - outputs**2) logabsdet = utils.sum_except_batch(logabsdet, num_batch_dims=1) return outputs, logabsdet
def _coupling_transform_inverse(self, inputs, transform_params): scale, shift = self._scale_and_shift(transform_params) log_scale = torch.log(scale) outputs = (inputs - shift) / scale logabsdet = -utils.sum_except_batch(log_scale, num_batch_dims=1) return outputs, logabsdet
def forward(self, inputs, context=None): outputs = (1 / np.pi) * torch.atan(inputs) + 0.5 logabsdet = utils.sum_except_batch(-np.log(np.pi) - torch.log(1 + inputs**2)) return outputs, logabsdet