def compute_mask(self, inputs, mask=None): if mask is None: return None if not isinstance(mask, list): raise ValueError('`mask` should be a list.') if not isinstance(inputs, list): raise ValueError('`inputs` should be a list.') if len(mask) != len(inputs): raise ValueError('The lists `inputs` and `mask` ' 'should have the same length.') if all([m is None for m in mask]): return None # Make a list of masks while making sure # the dimensionality of each mask # is the same as the corresponding input. masks = [] for input_i, mask_i in zip(inputs, mask): if mask_i is None: # Input is unmasked. Append all 1s to masks, # but cast it to bool first masks.append(K.cast(K.ones_like(input_i), 'bool')) elif K.ndim(mask_i) < K.ndim(input_i): # Mask is smaller than the input, expand it masks.append(K.expand_dims(mask_i)) else: masks.append(mask_i) concatenated = K.concatenate(masks, axis=self.axis) return K.all(concatenated, axis=-1, keepdims=False)
def call(self, inputs): if self._reshape_required: reshaped_inputs = [] input_ndims = list(map(K.ndim, inputs)) if None not in input_ndims: # If ranks of all inputs are available, # we simply expand each of them at axis=1 # until all of them have the same rank. max_ndim = max(input_ndims) for x in inputs: x_ndim = K.ndim(x) for _ in range(max_ndim - x_ndim): x = K.expand_dims(x, 1) reshaped_inputs.append(x) return self._merge_function(reshaped_inputs) else: # Transpose all inputs so that batch size is the last dimension. # (batch_size, dim1, dim2, ... ) -> (dim1, dim2, ... , batch_size) transposed = False for x in inputs: x_ndim = K.ndim(x) if x_ndim is None: x_shape = K.shape(x) batch_size = x_shape[0] new_shape = K.concatenate([x_shape[1:], K.expand_dims(batch_size)]) x_transposed = K.reshape(x, K.stack([batch_size, K.prod(x_shape[1:])])) x_transposed = K.permute_dimensions(x_transposed, (1, 0)) x_transposed = K.reshape(x_transposed, new_shape) reshaped_inputs.append(x_transposed) transposed = True elif x_ndim > 1: dims = list(range(1, x_ndim)) + [0] reshaped_inputs.append(K.permute_dimensions(x, dims)) transposed = True else: # We don't transpose inputs if they are 1D vectors or scalars. reshaped_inputs.append(x) y = self._merge_function(reshaped_inputs) y_ndim = K.ndim(y) if transposed: # If inputs have been transposed, we have to transpose the output too. if y_ndim is None: y_shape = K.shape(y) y_ndim = K.shape(y_shape)[0] batch_size = y_shape[y_ndim - 1] new_shape = K.concatenate( [K.expand_dims(batch_size), y_shape[:y_ndim - 1]]) y = K.reshape(y, (-1, batch_size)) y = K.permute_dimensions(y, (1, 0)) y = K.reshape(y, new_shape) elif y_ndim > 1: dims = [y_ndim - 1] + list(range(y_ndim - 1)) y = K.permute_dimensions(y, dims) return y else: return self._merge_function(inputs)
def call(self, inputs): x1 = inputs[0] x2 = inputs[1] if isinstance(self.axes, int): if self.axes < 0: axes = [self.axes % K.ndim(x1), self.axes % K.ndim(x2)] else: axes = [self.axes] * 2 else: axes = [] for i in range(len(self.axes)): if self.axes[i] < 0: axes.append(self.axes[i] % K.ndim(inputs[i])) else: axes.append(self.axes[i]) if self.normalize: x1 = K.l2_normalize(x1, axis=axes[0]) x2 = K.l2_normalize(x2, axis=axes[1]) output = K.batch_dot(x1, x2, axes) return output
def softmax(x): ndim = K.ndim(x) if ndim == 2: return K.softmax(x) elif ndim == 3: e = K.exp(x - K.max(x, axis=-1, keepdims=True)) s = K.sum(e, axis=-1, keepdims=True) return e / s else: raise ValueError('Cannot apply softmax to a tensor ' 'that is not 2D or 3D. ' 'Here, ndim=' + str(ndim))
def softmax(x, axis=-1): """Softmax activation function. Arguments: x : Tensor. axis: Integer, axis along which the softmax normalization is applied. Returns: Tensor, output of softmax transformation. Raises: ValueError: In case `dim(x) == 1`. """ ndim = K.ndim(x) if ndim == 2: return K.softmax(x) elif ndim > 2: e = K.exp(x - K.max(x, axis=axis, keepdims=True)) s = K.sum(e, axis=axis, keepdims=True) return e / s else: raise ValueError('Cannot apply softmax to a tensor that is 1D')
def softmax(x, axis=-1): """Softmax activation function. Arguments: x : Tensor. axis: Integer, axis along which the softmax normalization is applied. Returns: Tensor, output of softmax transformation. Raises: ValueError: In case `dim(x) == 1`. """ ndim = K.ndim(x) if ndim == 2: return K.softmax(x) elif ndim > 2: e = K.exp(x - K.max(x, axis=axis, keepdims=True)) s = K.sum(e, axis=axis, keepdims=True) return e / s else: raise ValueError('Cannot apply softmax to a tensor that is 1D')