I have used an activation function that I have created on my own (not usually) and I used for my LSTM. Everything went well, I trained my model and saved it as .h5 file.
Here is my customized activation function:
from keras import backend as kdef activate(ab): a = k.exp(ab[:, 0]) b = k.softplus(ab[:, 1]) a = k.reshape(a, (k.shape(a)[0], 1)) b = k.reshape(b, (k.shape(b)[0], 1)) return k.concatenate((a, b), axis=1)def weibull_loglik_discrete(y_true, ab_pred, name=None): y_ = y_true[:, 0] u_ = y_true[:, 1] a_ = ab_pred[:, 0] b_ = ab_pred[:, 1] hazard0 = k.pow((y_ + 1e-35) / a_, b_) hazard1 = k.pow((y_ + 1) / a_, b_) return -1 * k.mean(u_ * k.log(k.exp(hazard1 - hazard0) - 1.0) - hazard1)model = Sequential()model.add(Masking(mask_value=0., input_shape=(max_time, 39)))model.add(LSTM(20, input_dim=11))model.add(Dense(2))# Apply the custom activation function mentioned abovemodel.add(Activation(activate))# discrete log-likelihood for Weibull survival data as my loss functionmodel.compile(loss=weibull_loglik_discrete, optimizer=RMSprop(lr=.001)) # Fit!model.fit(train_x, train_y, nb_epoch=250, batch_size=2000, verbose=2, validation_data=(test_x, test_y))After training, I save my model as follow:
from keras.models import load_modelmodel.save("model_baseline_lstm.h5")Later, when I try to load the model, I run this :
from keras.models import load_modelmodel= load_model("model_baseline_lstm.h5")BUT, I get this error:
--------------------------------------------------------------------------- ValueErrorTraceback (most recent call last) <ipython-input-11-d3f9f7415b5c> in <module>() 13 # model.save("model_baseline_lsm.h5") 14 from keras.models import load_model---> 15 model= load_model("model_baseline_lsm.h5")/anaconda3/lib/python3.6/site-packages/keras/models.py in load_model(filepath, custom_objects, compile) 238 raise ValueError('No model found in config file.') 239 model_config = json.loads(model_config.decode('utf-8'))--> 240 model = model_from_config(model_config, custom_objects=custom_objects) 241 242 # set weights/anaconda3/lib/python3.6/site-packages/keras/models.py in model_from_config(config, custom_objects) 312 'Maybe you meant to use ' 313 '`Sequential.from_config(config)`?')--> 314 return layer_module.deserialize(config, custom_objects=custom_objects) 315 316 /anaconda3/lib/python3.6/site-packages/keras/layers/__init__.py in deserialize(config, custom_objects) 53 module_objects=globs, 54 custom_objects=custom_objects,---> 55 printable_module_name='layer')/anaconda3/lib/python3.6/site-packages/keras/utils/generic_utils.py in deserialize_keras_object(identifier, module_objects, custom_objects, printable_module_name) 138 return cls.from_config(config['config'], 139 custom_objects=dict(list(_GLOBAL_CUSTOM_OBJECTS.items()) +--> 140 list(custom_objects.items()))) 141 with CustomObjectScope(custom_objects): 142 return cls.from_config(config['config'])/anaconda3/lib/python3.6/site-packages/keras/models.py in from_config(cls, config, custom_objects) 1321 model = cls() 1322 for conf in config:-> 1323 layer = layer_module.deserialize(conf, custom_objects=custom_objects) 1324 model.add(layer) 1325 return model/anaconda3/lib/python3.6/site-packages/keras/layers/__init__.py in deserialize(config, custom_objects) 53 module_objects=globs, 54 custom_objects=custom_objects,---> 55 printable_module_name='layer')/anaconda3/lib/python3.6/site-packages/keras/utils/generic_utils.py in deserialize_keras_object(identifier, module_objects, custom_objects, printable_module_name) 140 list(custom_objects.items()))) 141 with CustomObjectScope(custom_objects):--> 142 return cls.from_config(config['config']) 143 else: 144 # Then `cls` may be a function returning a class./anaconda3/lib/python3.6/site-packages/keras/engine/topology.py in from_config(cls, config) 1251 A layer instance. 1252 """-> 1253 return cls(**config) 1254 1255 def count_params(self):/anaconda3/lib/python3.6/site-packages/keras/layers/core.py in__init__(self, activation, **kwargs) 289 super(Activation, self).__init__(**kwargs) 290 self.supports_masking = True--> 291 self.activation = activations.get(activation) 292 293 def call(self, inputs):/anaconda3/lib/python3.6/site-packages/keras/activations.py in get(identifier) 93 if isinstance(identifier, six.string_types): 94 identifier = str(identifier)---> 95 return deserialize(identifier) 96 elif callable(identifier): 97 if isinstance(identifier, Layer):/anaconda3/lib/python3.6/site-packages/keras/activations.py in deserialize(name, custom_objects) 85 module_objects=globals(), 86 custom_objects=custom_objects,---> 87 printable_module_name='activation function') 88 89 /anaconda3/lib/python3.6/site-packages/keras/utils/generic_utils.py in deserialize_keras_object(identifier, module_objects, custom_objects, printable_module_name) 158 if fn is None: 159 raise ValueError('Unknown '+ printable_module_name +--> 160 ':'+ function_name) 161 return fn 162 else:ValueError: Unknown activation function:activate