Python keras.losses.categorical_crossentropy() Examples

def nn_model():
    (x_train, y_train), _ = mnist.load_data()
    # 归一化
    x_train = x_train.reshape(x_train.shape[0], -1) / 255.
    # one-hot
    y_train = np_utils.to_categorical(y=y_train, num_classes=10)
    # constant(value=1.)自定义常数，constant(value=1.)===one()
    # 创建模型:输入784个神经元，输出10个神经元
    model = Sequential([
        Dense(units=200, input_dim=784, bias_initializer=constant(value=1.), activation=tanh),
        Dense(units=100, bias_initializer=one(), activation=tanh),
        Dense(units=10, bias_initializer=one(), activation=softmax),
    ])

    opt = SGD(lr=0.2, clipnorm=1.)  # 优化器
    model.compile(optimizer=opt, loss=categorical_crossentropy, metrics=['acc', 'mae'])  # 编译
    model.fit(x_train, y_train, batch_size=64, epochs=20, callbacks=[RemoteMonitor()])
    model_save(model, './model.h5') 

def get_model_compiled(shapeinput, num_class, w_decay=0, lr=1e-3):
    clf = Sequential()
    clf.add(Conv3D(32, kernel_size=(5, 5, 24), input_shape=shapeinput))
    clf.add(BatchNormalization())
    clf.add(Activation('relu'))
    clf.add(Conv3D(64, (5, 5, 16)))
    clf.add(BatchNormalization())
    clf.add(Activation('relu'))
    clf.add(MaxPooling3D(pool_size=(2, 2, 1)))
    clf.add(Flatten())
    clf.add(Dense(300, kernel_regularizer=regularizers.l2(w_decay)))
    clf.add(BatchNormalization())
    clf.add(Activation('relu'))
    clf.add(Dense(num_class, activation='softmax'))
    clf.compile(loss=categorical_crossentropy, optimizer=Adam(lr=lr), metrics=['accuracy'])
    return clf 

def crf_loss(y_true, y_pred):
    """General CRF loss function depending on the learning mode.

    # Arguments
        y_true: tensor with true targets.
        y_pred: tensor with predicted targets.

    # Returns
        If the CRF layer is being trained in the join mode, returns the negative
        log-likelihood. Otherwise returns the categorical crossentropy implemented
        by the underlying Keras backend.

    # About GitHub
        If you open an issue or a pull request about CRF, please
        add `cc @lzfelix` to notify Luiz Felix.
    """
    crf, idx = y_pred._keras_history[:2]
    if crf.learn_mode == 'join':
        return crf_nll(y_true, y_pred)
    else:
        if crf.sparse_target:
            return sparse_categorical_crossentropy(y_true, y_pred)
        else:
            return categorical_crossentropy(y_true, y_pred) 

def crf_loss(y_true, y_pred):
    """General CRF loss function depending on the learning mode.
    # Arguments
        y_true: tensor with true targets.
        y_pred: tensor with predicted targets.
    # Returns
        If the CRF layer is being trained in the join mode, returns the negative
        log-likelihood. Otherwise returns the categorical crossentropy implemented
        by the underlying Keras backend.
    # About GitHub
        If you open an issue or a pull request about CRF, please
        add `cc @lzfelix` to notify Luiz Felix.
    """
    crf, idx = y_pred._keras_history[:2]
    if crf.learn_mode == 'join':
        return crf_nll(y_true, y_pred)
    else:
        if crf.sparse_target:
            return sparse_categorical_crossentropy(y_true, y_pred)
        else:
            return categorical_crossentropy(y_true, y_pred)

# crf_marginal_accuracy, crf_viterbi_accuracy 

def iris():

    from keras.optimizers import Adam, Nadam
    from keras.losses import logcosh, categorical_crossentropy
    from keras.activations import relu, elu, softmax

    # here use a standard 2d dictionary for inputting the param boundaries
    p = {'lr': (0.5, 5, 10),
         'first_neuron': [4, 8, 16, 32, 64],
         'hidden_layers': [0, 1, 2, 3, 4],
         'batch_size': (2, 30, 10),
         'epochs': [2],
         'dropout': (0, 0.5, 5),
         'weight_regulizer': [None],
         'emb_output_dims':  [None],
         'shapes': ['brick', 'triangle', 0.2],
         'optimizer': [Adam, Nadam],
         'losses': [logcosh, categorical_crossentropy],
         'activation': [relu, elu],
         'last_activation': [softmax]}

    return p 

def create_model(input_shape: tuple, nb_classes: int, init_with_imagenet: bool = False, learning_rate: float = 0.01):
    weights = None
    if init_with_imagenet:
        weights = "imagenet"

    model = VGG16(input_shape=input_shape,
                  classes=nb_classes,
                  weights=weights,
                  include_top=False)
    # "Shallow" VGG for Cifar10
    x = model.get_layer('block3_pool').output
    x = layers.Flatten(name='Flatten')(x)
    x = layers.Dense(512, activation='relu')(x)
    x = layers.Dense(nb_classes)(x)
    x = layers.Softmax()(x)
    model = models.Model(model.input, x)

    loss = losses.categorical_crossentropy
    optimizer = optimizers.SGD(lr=learning_rate, decay=0.99)

    model.compile(optimizer, loss, metrics=["accuracy"])
    return model 

def _init_model(self):
        """
        Initialize base model from Keras and add top layers to match number of training emotions labels.
        :return:
        """
        base_model = self._get_base_model()

        top_layer_model = base_model.output
        top_layer_model = GlobalAveragePooling2D()(top_layer_model)
        top_layer_model = Dense(1024, activation='relu')(top_layer_model)
        prediction_layer = Dense(output_dim=len(self.emotion_map.keys()), activation='softmax')(top_layer_model)

        model = Model(input=base_model.input, output=prediction_layer)
        print(model.summary())
        for layer in base_model.layers:
            layer.trainable = False
        model.compile(optimizer='rmsprop', loss='categorical_crossentropy', metrics=['accuracy'])

        self.model = model 

def fit(self, features, labels, validation_split, epochs=50):
        """
        Trains the neural net on the data provided.

        :param features: Numpy array of training data.
        :param labels: Numpy array of target (label) data.
        :param validation_split: Float between 0 and 1. Percentage of training data to use for validation
        :param epochs: Max number of times to train over dataset.
        """
        self.model.fit(x=features, y=labels, epochs=epochs, verbose=1,
                       callbacks=[ReduceLROnPlateau(), EarlyStopping(patience=3)], validation_split=validation_split,
                       shuffle=True)

        for layer in self.model.layers[:self._NUM_BOTTOM_LAYERS_TO_RETRAIN]:
            layer.trainable = False
        for layer in self.model.layers[self._NUM_BOTTOM_LAYERS_TO_RETRAIN:]:
            layer.trainable = True

        self.model.compile(optimizer='sgd', loss='categorical_crossentropy', metrics=['accuracy'])
        self.model.fit(x=features, y=labels, epochs=50, verbose=1,
                       callbacks=[ReduceLROnPlateau(), EarlyStopping(patience=3)], validation_split=validation_split,
                       shuffle=True) 

def cnn_model():
    (x_train, y_train), _ = mnist.load_data()
    # 归一化
    x_train = x_train.reshape(-1, 28, 28, 1) / 255.
    # one-hot
    y_train = np_utils.to_categorical(y=y_train, num_classes=10)

    model = Sequential([
        # input_shape:输入平面，就在第一个位置设置
        # filters：卷积核、滤波器
        # kernel_size：卷积核大小
        # strides：步长
        # padding有两种方式：same/valid
        # activation：激活函数
        Convolution2D(input_shape=(28, 28, 1), filters=32, kernel_size=5, strides=1, padding='same', activation=relu),
        MaxPool2D(pool_size=2, strides=2, padding='same'),
        Convolution2D(filters=64, kernel_size=5, padding='same', activation=relu),
        MaxPool2D(pool_size=2, trainable=2, padding='same'),
        Flatten(),  # 扁平化
        Dense(units=1024, activation=relu),
        Dropout(0.5),
        Dense(units=10, activation=softmax),
    ])
    opt = Adam(lr=1e-4)
    model.compile(optimizer=opt, loss=categorical_crossentropy, metrics=['accuracy'])
    model.fit(x=x_train, y=y_train, batch_size=64, epochs=20, callbacks=[RemoteMonitor()])
    model_save(model, './model.h5') 

def rnn_model():
    (x_train, y_train), _ = mnist.load_data()
    # 归一化
    x_train = x_train / 255.
    # one-hot
    y_train = np_utils.to_categorical(y=y_train, num_classes=10)

    model = Sequential([
        SimpleRNN(units=50, input_shape=(28, 28)),
        Dense(units=10, activation=softmax),
    ])
    opt = RMSprop(lr=1e-4)
    model.compile(optimizer=opt, loss=categorical_crossentropy, metrics=['accuracy'])
    model.fit(x=x_train, y=y_train, batch_size=64, epochs=20, callbacks=[RemoteMonitor()])
    model_save(model, './model.h5') 

def masked_categorical_crossentropy(gt, pr):
    from keras.losses import categorical_crossentropy
    mask = 1 - gt[:, :, 0]
    return categorical_crossentropy(gt, pr) * mask 

def test_functional_model_saving():
    img_rows, img_cols = 32, 32
    img_channels = 3

    # Parameters for the DenseNet model builder
    img_dim = (img_channels, img_rows, img_cols) if K.image_data_format() == 'channels_first' else (
        img_rows, img_cols, img_channels)
    depth = 40
    nb_dense_block = 3
    growth_rate = 3  # number of z2 maps equals growth_rate * group_size, so keep this small.
    nb_filter = 16
    dropout_rate = 0.0  # 0.0 for data augmentation
    conv_group = 'D4'  # C4 includes 90 degree rotations, D4 additionally includes reflections in x and y axis.
    use_gcnn = True

    # Create the model (without loading weights)
    model = GDenseNet(mc_dropout=False, padding='same', nb_dense_block=nb_dense_block, growth_rate=growth_rate,
                      nb_filter=nb_filter, dropout_rate=dropout_rate, weights=None, input_shape=img_dim, depth=depth,
                      use_gcnn=use_gcnn, conv_group=conv_group)
    model.compile(loss=losses.categorical_crossentropy,
                  optimizer=optimizers.Adam(),
                  metrics=[metrics.categorical_accuracy])
    x = np.random.random((1, 32, 32, 3))
    y = np.random.randint(0, 10, 1)
    y = np_utils.to_categorical(y, 10)
    model.train_on_batch(x, y)

    out = model.predict(x)
    _, fname = tempfile.mkstemp('.h5')
    save_model(model, fname)

    model = load_model(fname)
    os.remove(fname)

    out2 = model.predict(x)
    assert_allclose(out, out2, atol=1e-05) 

def get_model_compiled(shapeinput, num_class, w_decay=0):
    clf = Sequential()
    clf.add(Conv2D(50, kernel_size=(5, 5), input_shape=shapeinput))
    clf.add(Activation('relu'))
    clf.add(Conv2D(100, (5, 5)))
    clf.add(Activation('relu'))
    clf.add(MaxPooling2D(pool_size=(2, 2)))
    clf.add(Flatten())
    clf.add(Dense(100, kernel_regularizer=regularizers.l2(w_decay)))
    clf.add(Activation('relu'))
    clf.add(Dense(num_class, activation='softmax'))
    clf.compile(loss=categorical_crossentropy, optimizer=Adam(), metrics=['accuracy'])
    return clf 

def get_model_compiled(bands, num_class):
    clf = Sequential()
    clf.add(Conv1D(20, (24), activation='relu', input_shape=(bands,1)))
    clf.add(MaxPooling1D(pool_size=5))
    clf.add(Flatten())
    clf.add(Dense(100))
    clf.add(BatchNormalization())
    clf.add(Activation('relu'))
    clf.add(Dense(num_class, activation='softmax'))
    clf.compile(loss=categorical_crossentropy, optimizer=Adam(), metrics=['accuracy'])
    return clf 

def get_model_compiled(feat_size, seq_len, num_class, type_func):
    if type_func == "RNN": func = SimpleRNN
    elif type_func == "GRU": func = CuDNNGRU
    elif type_func == "LSTM": func = CuDNNLSTM
    else: print("NOT RECURRENT FUNC")
    clf = Sequential()
    clf.add(func(64, return_sequences=True, input_shape=(feat_size, seq_len)))
    clf.add(func(64, return_sequences=True))
    clf.add(Flatten())
    clf.add(Dense(num_class, activation='softmax'))
    clf.compile(loss=categorical_crossentropy, optimizer=Adam(), metrics=['accuracy'])
    return clf 

def get_model_compiled(args, inputshape, num_class):
    model = Sequential()
    if args.arch == "CNN1D":
        model.add(Conv1D(20, (24), activation='relu', input_shape=inputshape))
        model.add(MaxPooling1D(pool_size=5))
        model.add(Flatten())
        model.add(Dense(100))
    elif "CNN2D" in args.arch:
        model.add(Conv2D(50, kernel_size=(5, 5), input_shape=inputshape))
        model.add(Activation('relu'))
        model.add(Conv2D(100, (5, 5)))
        model.add(Activation('relu'))
        model.add(MaxPooling2D(pool_size=(2, 2)))
        model.add(Flatten())
        model.add(Dense(100))
    elif args.arch == "CNN3D":
        model.add(Conv3D(32, kernel_size=(5, 5, 24), input_shape=inputshape))
        model.add(BatchNormalization())
        model.add(Activation('relu'))
        model.add(Conv3D(64, (5, 5, 16)))
        model.add(BatchNormalization())
        model.add(Activation('relu'))
        model.add(MaxPooling3D(pool_size=(2, 2, 1)))
        model.add(Flatten())
        model.add(Dense(300))
    if args.arch != "CNN2D": model.add(BatchNormalization())
    model.add(Activation('relu'))
    model.add(Dense(num_class, activation='softmax'))
    model.compile(loss=categorical_crossentropy, optimizer=Adam(args.lr1), metrics=['accuracy']) 
    return model 

def get_model_compiled(n_bands, num_class):
    clf = Sequential()
    clf.add(Dense(int(n_bands*2/3.)+10, activation='relu', input_shape=(n_bands,)))
    clf.add(Dense(num_class, activation='softmax'))
    clf.compile(loss=categorical_crossentropy, optimizer=Adam(), metrics=['accuracy'])
    return clf 

def test_updatable_model_flag_off(self):
        """
        Test to ensure that when respect_trainable is off, then we will ignore
        any 'trainable' layers of the original network.
        """
        import coremltools
        from keras.layers import Dense
        from keras.losses import categorical_crossentropy
        from keras.optimizers import SGD

        input = ["data"]
        output = ["output"]
        # First, set respect_trainable to False and then check to make sure the
        # converted model is NOT updatable.
        not_updatable = Sequential()
        not_updatable.add(Dense(128, input_shape=(16,)))
        # layer is updatable, but the flag during convert is false, so that bit
        # must get dropped on the floor.
        not_updatable.add(Dense(10, name="foo", activation="softmax", trainable=True))
        not_updatable.compile(
            loss=categorical_crossentropy, optimizer=SGD(lr=0.01), metrics=["accuracy"]
        )
        cml = coremltools.converters.keras.convert(
            not_updatable, input, output, respect_trainable=False
        )
        spec = cml.get_spec()
        self.assertFalse(spec.isUpdatable)
        layers = spec.neuralNetwork.layers
        self.assertIsNotNone(layers[1].innerProduct)
        self.assertTrue(layers[1].innerProduct)
        self.assertFalse(layers[1].isUpdatable) 

def test_updatable_model_flag_cce_sgd(self):
        """
        Test to ensure that respect_trainable is honored during convert of a
        model with categorical cross entropy loss and SGD optimizer.
        """
        import coremltools
        from keras.layers import Dense
        from keras.losses import categorical_crossentropy
        from keras.optimizers import SGD

        input = ["data"]
        output = ["output"]

        # This should result in an updatable model.
        updatable = Sequential()
        updatable.add(Dense(128, input_shape=(16,)))
        updatable.add(Dense(10, name="foo", activation="softmax", trainable=True))
        updatable.compile(
            loss=categorical_crossentropy, optimizer=SGD(lr=1.0), metrics=["accuracy"]
        )
        cml = coremltools.converters.keras.convert(
            updatable, input, output, respect_trainable=True
        )
        spec = cml.get_spec()
        self.assertTrue(spec.isUpdatable)
        layers = spec.neuralNetwork.layers
        self.assertIsNotNone(layers[1].innerProduct)
        self.assertTrue(layers[1].innerProduct)
        self.assertTrue(layers[1].isUpdatable)
        self.assertEqual(len(spec.neuralNetwork.updateParams.lossLayers), 1)
        sgdopt = spec.neuralNetwork.updateParams.optimizer.sgdOptimizer
        self.assertEqual(sgdopt.learningRate.defaultValue, 1.0)
        self.assertEqual(sgdopt.miniBatchSize.defaultValue, 16)
        self.assertEqual(sgdopt.momentum.defaultValue, 0.0) 

def test_updatable_model_flag_functional(self):
        """
        Test to ensure that respect_trainable is honored during convert of a
        Keras model defined via the Keras functional API.
        """
        import coremltools
        from keras.layers import Dense, Input
        from keras.losses import categorical_crossentropy
        from keras.optimizers import SGD

        input = ["data"]
        output = ["output"]

        # This should result in an updatable model.
        inputs = Input(shape=(16,))
        d1 = Dense(128)(inputs)
        d2 = Dense(10, name="foo", activation="softmax", trainable=True)(d1)
        kmodel = Model(inputs=inputs, outputs=d2)
        kmodel.compile(
            loss=categorical_crossentropy, optimizer=SGD(lr=1.0), metrics=["accuracy"]
        )
        cml = coremltools.converters.keras.convert(
            kmodel, input, output, respect_trainable=True
        )
        spec = cml.get_spec()
        self.assertTrue(spec.isUpdatable)
        layers = spec.neuralNetwork.layers
        self.assertIsNotNone(layers[1].innerProduct)
        self.assertTrue(layers[1].innerProduct)
        self.assertTrue(layers[1].isUpdatable)
        self.assertEqual(len(spec.neuralNetwork.updateParams.lossLayers), 1)
        sgdopt = spec.neuralNetwork.updateParams.optimizer.sgdOptimizer
        self.assertEqual(sgdopt.learningRate.defaultValue, 1.0)
        self.assertEqual(sgdopt.miniBatchSize.defaultValue, 16)
        self.assertEqual(sgdopt.momentum.defaultValue, 0.0) 

def test_updatable_model_flag_cce_sgd_string(self):
        """
        Tests the 'respect_trainable' flag when used along with string
        for the optimizer(keras internally creates an instance, here sgd),
        conversion is successful
        """
        import coremltools
        from keras.layers import Dense, Input
        from keras.losses import categorical_crossentropy

        input = ["data"]
        output = ["output"]

        # This should result in an updatable model.
        inputs = Input(shape=(16,))
        d1 = Dense(128)(inputs)
        d2 = Dense(10, name="foo", activation="softmax", trainable=True)(d1)
        kmodel = Model(inputs=inputs, outputs=d2)
        kmodel.compile(
            loss=categorical_crossentropy, optimizer="sgd", metrics=["accuracy"]
        )
        cml = coremltools.converters.keras.convert(
            kmodel, input, output, respect_trainable=True
        )
        spec = cml.get_spec()
        self.assertTrue(spec.isUpdatable)
        layers = spec.neuralNetwork.layers
        self.assertIsNotNone(layers[1].innerProduct)
        self.assertTrue(layers[1].innerProduct)
        self.assertTrue(layers[1].isUpdatable)
        self.assertEqual(len(spec.neuralNetwork.updateParams.lossLayers), 1)
        sgdopt = spec.neuralNetwork.updateParams.optimizer.sgdOptimizer
        # use almost equal for default verification with at least 5 decimal
        # places of closeness
        self.assertAlmostEqual(sgdopt.learningRate.defaultValue, 0.01, places=5)
        self.assertEqual(sgdopt.miniBatchSize.defaultValue, 16)
        self.assertEqual(sgdopt.momentum.defaultValue, 0.0) 

def test_updatable_model_flag_cce_adam_string(self):
        """
        Tests the 'respect_trainable' flag when used along with string
        for the optimizer(keras internally creates an instance, here adam),
        conversion is successful
        """
        import coremltools
        from keras.layers import Dense, Input
        from keras.losses import categorical_crossentropy

        input = ["data"]
        output = ["output"]

        # This should result in an updatable model.
        inputs = Input(shape=(16,))
        d1 = Dense(128)(inputs)
        d2 = Dense(10, name="foo", activation="softmax", trainable=True)(d1)
        kmodel = Model(inputs=inputs, outputs=d2)
        kmodel.compile(
            loss=categorical_crossentropy, optimizer="adam", metrics=["accuracy"]
        )
        cml = coremltools.converters.keras.convert(
            kmodel, input, output, respect_trainable=True
        )
        spec = cml.get_spec()
        self.assertTrue(spec.isUpdatable)
        layers = spec.neuralNetwork.layers
        self.assertIsNotNone(layers[1].innerProduct)
        self.assertTrue(layers[1].innerProduct)
        self.assertTrue(layers[1].isUpdatable)
        self.assertEqual(len(spec.neuralNetwork.updateParams.lossLayers), 1)
        adopt = spec.neuralNetwork.updateParams.optimizer.adamOptimizer
        # use almost equal for default verification with at least 5 decimal
        # places of closeness
        self.assertAlmostEqual(adopt.learningRate.defaultValue, 0.001, places=5)
        self.assertAlmostEqual(adopt.miniBatchSize.defaultValue, 16)
        self.assertAlmostEqual(adopt.beta1.defaultValue, 0.90, places=5)
        self.assertAlmostEqual(adopt.beta2.defaultValue, 0.999, places=5) 

def compute_egls(self, unlabeled, n_classes):

        # create a function for computing the gradient length:
        self.input_placeholder = K.placeholder(self.model.get_input_shape_at(0))
        self.output_placeholder = K.placeholder(self.model.get_output_shape_at(0))
        predict = self.model.call(self.input_placeholder)
        loss = K.mean(categorical_crossentropy(self.output_placeholder, predict))
        weights = [tensor for tensor in self.model.trainable_weights]
        gradient = self.model.optimizer.get_gradients(loss, weights)
        gradient_flat = [K.flatten(x) for x in gradient]
        gradient_flat = K.concatenate(gradient_flat)
        gradient_length = K.sum(K.square(gradient_flat))
        self.get_gradient_length = K.function([K.learning_phase(), self.input_placeholder, self.output_placeholder], [gradient_length])

        # calculate the expected gradient length of the unlabeled set (iteratively, to avoid memory issues):
        unlabeled_predictions = self.model.predict(unlabeled)
        egls = np.zeros(unlabeled.shape[0])
        for i in range(n_classes):
            calculated_so_far = 0
            while calculated_so_far < unlabeled_predictions.shape[0]:
                if calculated_so_far + 100 >= unlabeled_predictions.shape[0]:
                    next = unlabeled_predictions.shape[0] - calculated_so_far
                else:
                    next = 100

                labels = np.zeros((next, n_classes))
                labels[:,i] = 1
                grads = self.get_gradient_length([0, unlabeled[calculated_so_far:calculated_so_far+next, :], labels])[0]
                grads *= unlabeled_predictions[calculated_so_far:calculated_so_far+next, i]
                egls[calculated_so_far:calculated_so_far+next] += grads

                calculated_so_far += next

        return egls 

def cce_loss_graph(gt, pr):
    return K.mean(categorical_crossentropy(gt, pr)) 

def test_weighted_masked_objective():
    a = Input(shape=(3,), name='input_a')

    # weighted_masked_objective
    def mask_dummy(y_true=None, y_pred=None, weight=None):
        return K.placeholder(y_true.shape)

    weighted_function = _weighted_masked_objective(losses.categorical_crossentropy)
    weighted_function(a, a, None) 

def test_check_not_failing():
    a = np.random.random((2, 1, 3))
    _check_loss_and_target_compatibility([a], [losses.categorical_crossentropy], [a.shape])
    _check_loss_and_target_compatibility([a], [losses.categorical_crossentropy], [(2, None, 3)]) 

def test_check_last_is_one():
    a = np.random.random((2, 3, 1))
    with pytest.raises(ValueError) as exc:
        _check_loss_and_target_compatibility([a], [losses.categorical_crossentropy], [a.shape])

    assert 'You are passing a target array' in str(exc) 

def test_check_bad_shape():
    a = np.random.random((2, 3, 5))
    with pytest.raises(ValueError) as exc:
        _check_loss_and_target_compatibility([a], [losses.categorical_crossentropy], [(2, 3, 6)])

    assert 'targets to have the same shape' in str(exc) 

def test_weighted_masked_objective():
    a = Input(shape=(3,), name='input_a')

    # weighted_masked_objective
    def mask_dummy(y_true=None, y_pred=None, weight=None):
        return K.placeholder(y_true.shape)

    weighted_function = _weighted_masked_objective(losses.categorical_crossentropy)
    weighted_function(a, a, None) 

def test_check_last_is_one():
    a = np.random.random((2, 3, 1))
    with pytest.raises(ValueError) as exc:
        _check_loss_and_target_compatibility([a], [losses.categorical_crossentropy], [a.shape])

    assert 'You are passing a target array' in str(exc)