def convert_optimizer_trial_to_hps(
hps: hp_module.HyperParameters,
optimizer_trial: Dict[Text, Any]) -> hp_module.HyperParameters:
"""Converts Optimizer Trial parameters into KerasTuner HyperParameters."""
hps = hp_module.HyperParameters.from_config(hps.get_config())
hps.values = {}
for param in optimizer_trial["parameters"]:
if "floatValue" in param:
hps.values[param["parameter"]] = float(param["floatValue"])
if "intValue" in param:
hps.values[param["parameter"]] = int(param["intValue"])
if "stringValue" in param:
hps.values[param["parameter"]] = str(param["stringValue"])
return hps
def convert_vizier_trial_to_hps(
hps: hp_module.HyperParameters,
vizier_trial: Dict[Text, Any]) -> hp_module.HyperParameters:
"""Converts Vizier Trial parameters into KerasTuner HyperParameters.
Args:
hps: Sample KerasTuner HyperParameters object for config initialization
vizier_trial: A Vizier Trial instance.
Returns:
A KerasTuner HyperParameters object that holds the Vizier Trial
parameters.
"""
hps = hp_module.HyperParameters.from_config(hps.get_config())
hps.values = convert_vizier_trial_to_dict(vizier_trial)
return hps
def _verify_output(self):
# Test best hparams.
best_hparams_path = os.path.join(self._best_hparams.uri,
'best_hyperparameters.txt')
self.assertTrue(tf.io.gfile.exists(best_hparams_path))
with tf.io.gfile.GFile(best_hparams_path, mode='r') as f:
best_hparams_config = json.loads(f.read())
best_hparams = HyperParameters.from_config(best_hparams_config)
self.assertBetween(best_hparams.get('learning_rate'), 1e-4, 1.01)
self.assertBetween(best_hparams.get('num_layers'), 1, 5)
def convert_hyperparams_to_hparams(
hyperparams: hp_module.HyperParameters
) -> Dict[hparams_api.HParam, Any]:
"""Converts KerasTuner HyperParameters to TensorBoard HParams.
Args:
hyperparams: A KerasTuner HyperParameters instance
Returns:
A dict that maps TensorBoard HParams to current values.
"""
hparams = {}
for hp in hyperparams.space:
hparams_value = {}
try:
hparams_value = hyperparams.get(hp.name)
except ValueError:
continue
hparams_domain = {}
if isinstance(hp, hp_module.Choice):
hparams_domain = hparams_api.Discrete(hp.values)
elif isinstance(hp, hp_module.Int):
if hp.step is None or hp.step == 1:
hparams_domain = hparams_api.IntInterval(
hp.min_value, hp.max_value)
else:
# Note: `hp.max_value` is inclusive, unlike the end index
# of Python `range()`, which is exclusive
values = list(range(hp.min_value, hp.max_value + 1, hp.step))
hparams_domain = hparams_api.Discrete(values)
elif isinstance(hp, hp_module.Float):
if hp.step is None:
hparams_domain = hparams_api.RealInterval(
hp.min_value, hp.max_value)
else:
# Note: `hp.max_value` is inclusive, which is also
# the default for Numpy's linspace
num_samples = int((hp.max_value - hp.min_value) / hp.step)
end_value = hp.min_value + (num_samples * hp.step)
values = np.linspace(hp.min_value, end_value,
num_samples + 1).tolist()
hparams_domain = hparams_api.Discrete(values)
elif isinstance(hp, hp_module.Boolean):
hparams_domain = hparams_api.Discrete([True, False])
elif isinstance(hp, hp_module.Fixed):
hparams_domain = hparams_api.Discrete([hp.value])
else:
raise ValueError(
"`HyperParameter` type not recognized: {}".format(hp))
hparams_key = hparams_api.HParam(hp.name, hparams_domain)
hparams[hparams_key] = hparams_value
return hparams
def pretrain(self,inputs,outputs,iteration):
"""
Optimize the hyperparameters of the ANN.
Args:
inputs (np.array): All input data.
outputs (np.array): All output data.
iteration (int): Iteration number.
Returns:
best_hp (kerastuner.engine.hyperparameters.HyperParameters): Optimal hyperparameters.
Notes:
Optimization objective fixed on val_loss.
"""
print("### Performing Keras Tuner optimization of the ANN###")
# Select hyperparameters to tune
hp = HyperParameters()
valid_entries = ["activation","neurons","layers","learning_rate","regularization","sparsity"]
if not all([entry in valid_entries for entry in self["optimize"]]):
raise Exception("Invalid hyperparameters specified for optimization")
if "activation" in self["optimize"]:
hp.Choice("activation_function",["sigmoid","relu","swish","tanh"],default=self["activation"])
if "neurons" in self["optimize"]:
hp.Int("no_neurons",3,20,sampling="log",default=self["no_neurons"])
if "layers" in self["optimize"]:
hp.Int("no_hid_layers",1,6,default=self["no_layers"])
if "learning_rate" in self["optimize"]:
hp.Float("learning_rate",0.001,0.1,sampling="log",default=self["learning_rate"])
if "regularization" in self["optimize"]:
hp.Float("regularization",0.0001,0.01,sampling="log",default=self["kernel_regularizer"])
if "sparsity" in self["optimize"]:
hp.Float("sparsity",0.3,0.9,default=self["sparsity"])
no_hps = len(hp._space)
# In case none are chosen, only 1 run for fixed setting
if no_hps == 0:
hp.Fixed("no_neurons",self["no_neurons"])
# Load tuner
max_trials = self["max_trials"]*no_hps
path_tf_format = "logs"
time = datetime.now().strftime("%Y%m%d_%H%M")
tuner_args = {"objective":"val_loss","hyperparameters":hp,"max_trials":max_trials,
"executions_per_trial":self["executions_per_trial"],"directory":path_tf_format,
"overwrite":True,"tune_new_entries":False,"project_name":f"opt"}
## "overwrite":True,"tune_new_entries":False,"project_name":f"opt_{time}"}
if self["tuner"] == "random" or no_hps==0:
tuner = RandomSearchCV(self.build_hypermodel,**tuner_args)
elif self["tuner"] == "bayesian":
tuner = BayesianOptimizationCV(self.build_hypermodel,num_initial_points=3*no_hps,**tuner_args)
# Load callbacks and remove early stopping
callbacks_all = self.get_callbacks()
callbacks = [call for call in callbacks_all if not isinstance(call,keras.callbacks.EarlyStopping)]
# Optimize
tuner.search(inputs,outputs,epochs=self["tuner_epochs"],verbose=0,shuffle=True,
callbacks=callbacks,iteration_no=iteration)
# Retrieve and save best model
best_hp = tuner.get_best_hyperparameters()[0]
self.write_stats([best_hp.values],"ann_best_models")
# Make a table of tuner stats
scores = [tuner.oracle.trials[trial].score for trial in tuner.oracle.trials]
hps = [tuner.oracle.trials[trial].hyperparameters.values for trial in tuner.oracle.trials]
for idx,entry in enumerate(hps):
entry["score"] = scores[idx]
self.write_stats(hps,"ann_tuner_stats")
return best_hp
tuner = RandomSearch(
MyHyperModel(img_size=(28, 28), classes=10),
objective="val_accuracy",
max_trials=5,
directory="test_dir",
project_name="case3",
)
tuner.search(x, y=y, epochs=5, validation_data=(val_x, val_y))
# """Case #4:
# - We restrict the search space
# - This means that default values are being used for params that are left out
# """
hp = HyperParameters()
hp.Choice("learning_rate", [1e-1, 1e-3])
tuner = RandomSearch(
build_model,
max_trials=5,
hyperparameters=hp,
tune_new_entries=False,
objective="val_accuracy",
directory="test_dir",
project_name="case4",
)
tuner.search(x=x, y=y, epochs=5, validation_data=(val_x, val_y))
# """Case #5:
batch_size=16,
shuffle=True,
seed=7,
)
datagen_valid = datagen.flow_from_directory(
"archive/val",
color_mode="rgb",
class_mode="categorical",
target_size=(200, 200),
batch_size=16,
shuffle=True,
seed=7,
)
hp = HyperParameters()
def build_model(hp):
"""
建立模型
:return: 模型
"""
image_input = Input(shape=(200, 200, 3))
layer1_1 = Conv2D(hp.Choice('num_filters_layer1_1',
values=[16, 32, 64],
default=16), (1, 1),
activation='relu')(image_input)
#TensorShape([None, 200, 200, 64])
layer2_1 = Conv2D(hp.Choice('num_filters_layer2_1',
MyHyperModel(img_size=(28, 28), num_classes=10),
objective='val_accuracy',
max_trials=5,
directory='test_dir')
tuner.search(x,
y=y,
epochs=5,
validation_data=(val_x, val_y))
# """Case #4:
# - We restrict the search space
# - This means that default values are being used for params that are left out
# """
hp = HyperParameters()
hp.Choice('learning_rate', [1e-1, 1e-3])
tuner = RandomSearch(
build_model,
max_trials=5,
hyperparameters=hp,
tune_new_entries=False,
objective='val_accuracy')
tuner.search(x=x,
y=y,
epochs=5,
validation_data=(val_x, val_y))
# """Case #5: