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""" |
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Summary: |
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This module provides the main functionality of mcfly: searching for an |
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optimal model architecture. The work flow is as follows: |
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Function generate_models from modelgen.py generates and compiles models. |
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Function train_models_on_samples trains those models. |
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Function plotTrainingProcess plots the training process. |
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Function find_best_architecture is wrapper function that combines |
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these steps. |
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Example function calls can be found in the tutorial notebook |
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'EvaluateDifferentModels.ipynb'. |
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""" |
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import numpy as np |
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from . import modelgen |
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from .storage import TrainedModel |
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try: |
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import noodles |
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from .storage import serial_registry |
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except ImportError: |
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has_noodles = False |
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else: |
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has_noodles = True |
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from sklearn import neighbors, metrics as sklearnmetrics |
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import warnings |
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import json |
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import os |
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from keras.callbacks import EarlyStopping |
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from keras import metrics |
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def train_model( |
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model, X_train_sub, y_train_sub, epochs, batch_size, |
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validation_data, verbose, callbacks): |
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result = model.fit( |
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X_train_sub, |
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y_train_sub, |
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epochs=epochs, |
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batch_size=batch_size, # see comment on subsize_set |
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validation_data=validation_data, |
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verbose=verbose, |
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callbacks=callbacks) |
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# metric = result.history['val_' + metric_name][-1] |
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# loss = result.history['val_loss'][-1] |
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return TrainedModel( |
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history=result.history, model=model) # , metric=metric, loss=loss) |
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def train_models_on_samples(X_train, y_train, X_val, y_val, models, |
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nr_epochs=5, subset_size=100, verbose=True, outputfile=None, |
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model_path=None, early_stopping=False, |
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batch_size=20, metric='accuracy', use_noodles=None): |
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""" |
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Given a list of compiled models, this function trains |
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them all on a subset of the train data. If the given size of the subset is |
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smaller then the size of the data, the complete data set is used. |
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Parameters |
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---------- |
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X_train : numpy array of shape (num_samples, num_timesteps, num_channels) |
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The input dataset for training |
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y_train : numpy array of shape (num_samples, num_classes) |
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The output classes for the train data, in binary format |
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X_val : numpy array of shape (num_samples_val, num_timesteps, num_channels) |
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The input dataset for validation |
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y_val : numpy array of shape (num_samples_val, num_classes) |
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The output classes for the validation data, in binary format |
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models : list of model, params, modeltypes |
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List of keras models to train |
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nr_epochs : int, optional |
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nr of epochs to use for training one model |
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subset_size : |
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The number of samples used from the complete train set |
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verbose : bool, optional |
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flag for displaying verbose output |
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outputfile: str, optional |
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Filename to store the model training results |
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model_path : str, optional |
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Directory to store the models as HDF5 files |
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early_stopping: bool |
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Stop when validation loss does not decrease |
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batch_size : int |
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nr of samples per batch |
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metric : str |
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metric to store in the history object |
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Returns |
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---------- |
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histories : list of Keras History objects |
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train histories for all models |
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val_metrics : list of floats |
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validation accuraracies of the models |
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val_losses : list of floats |
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validation losses of the models |
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""" |
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# if subset_size is smaller then X_train, this will work fine |
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X_train_sub = X_train[:subset_size, :, :] |
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y_train_sub = y_train[:subset_size, :] |
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metric_name = get_metric_name(metric) |
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val_metrics = [] |
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val_losses = [] |
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def make_history(model, i=None): |
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model_metrics = [get_metric_name(name) for name in model.metrics] |
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if metric_name not in model_metrics: |
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raise ValueError( |
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'Invalid metric. The model was not compiled with {} as metric'.format(metric_name)) |
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if early_stopping: |
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callbacks = [ |
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EarlyStopping(monitor='val_loss', patience=0, verbose=verbose, mode='auto')] |
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else: |
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callbacks = [] |
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args = (model, X_train_sub, y_train_sub) |
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kwargs = {'epochs': nr_epochs, |
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'batch_size': batch_size, |
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'validation_data': (X_val, y_val), |
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'verbose': verbose, |
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'callbacks': callbacks} |
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if use_noodles is None: |
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# if not using noodles, save every nugget when it comes |
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trained_model = train_model(*args, **kwargs) |
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if outputfile is not None: |
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store_train_hist_as_json(models[i][1], models[i][2], |
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trained_model.history, outputfile) |
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if model_path is not None: |
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trained_model.save( |
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os.path.join(model_path, 'model_{}.h5'.format(i))) |
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return trained_model |
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else: |
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assert has_noodles, "Noodles is not installed, or could not be imported." |
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return noodles.schedule_hint(call_by_ref=['model']) \ |
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(train_model)(*args, **kwargs) |
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if use_noodles is None: |
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trained_models = [ |
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make_history(model[0], i) |
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for i, model in enumerate(models)] |
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else: |
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assert has_noodles, "Noodles is not installed, or could not be imported." |
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# in case of noodles, first run everything |
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training_wf = noodles.gather_all([make_history(model[0]) for model in models]) |
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trained_models = use_noodles(training_wf) |
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# then save everything |
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for i, (history, model) in enumerate(trained_models): |
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if outputfile is not None: |
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store_train_hist_as_json(models[i][1], models[i][2], |
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history, outputfile) |
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if model_path is not None: |
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model.save(os.path.join(model_path, 'model_{}.h5'.format(i))) |
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163
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# accumulate results |
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val_metrics = [tm.history['val_' + metric_name] |
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for tm in trained_models] |
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val_losses = [tm.history['val_loss'] |
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for tm in trained_models] |
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return [tm.history for tm in trained_models], val_metrics, val_losses |
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def store_train_hist_as_json(params, model_type, history, outputfile, metric_name='acc'): |
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""" |
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This function stores the model parameters, the loss and accuracy history |
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of one model in a JSON file. It appends the model information to the |
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existing models in the file. |
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Parameters |
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---------- |
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params : dict |
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parameters for one model |
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model_type : Keras model object |
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Keras model object for one model |
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history : dict |
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training history from one model |
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outputfile : str |
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path where the json file needs to be stored |
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metric_name : str, optional |
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name of metric from history to store |
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""" |
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jsondata = params.copy() |
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for k in jsondata.keys(): |
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if isinstance(jsondata[k], np.ndarray): |
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jsondata[k] = jsondata[k].tolist() |
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jsondata['train_metric'] = history[metric_name] |
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jsondata['train_loss'] = history['loss'] |
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jsondata['val_metric'] = history['val_' + metric_name] |
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jsondata['val_loss'] = history['val_loss'] |
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jsondata['modeltype'] = model_type |
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jsondata['metric'] = metric_name |
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if os.path.isfile(outputfile): |
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with open(outputfile, 'r') as outfile: |
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previousdata = json.load(outfile) |
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else: |
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previousdata = [] |
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previousdata.append(jsondata) |
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206
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with open(outputfile, 'w') as outfile: |
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json.dump(previousdata, outfile, sort_keys=True, |
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indent=4, ensure_ascii=False) |
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211
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def find_best_architecture(X_train, y_train, X_val, y_val, verbose=True, |
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212
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number_of_models=5, nr_epochs=5, subset_size=100, |
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outputpath=None, model_path=None, metric='accuracy', |
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use_noodles=None, **kwargs): |
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""" |
|
216
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Tries out a number of models on a subsample of the data, |
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217
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and outputs the best found architecture and hyperparameters. |
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218
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219
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Parameters |
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220
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---------- |
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221
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X_train : numpy array |
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222
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The input dataset for training of shape |
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223
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(num_samples, num_timesteps, num_channels) |
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224
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y_train : numpy array |
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225
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The output classes for the train data, in binary format of shape |
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(num_samples, num_classes) |
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X_val : numpy array |
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228
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The input dataset for validation of shape |
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229
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(num_samples_val, num_timesteps, num_channels) |
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y_val : numpy array |
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The output classes for the validation data, in binary format of shape |
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(num_samples_val, num_classes) |
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verbose : bool, optional |
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flag for displaying verbose output |
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number_of_models : int, optiona |
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The number of models to generate and test |
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nr_epochs : int, optional |
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The number of epochs that each model is trained |
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subset_size : int, optional |
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The size of the subset of the data that is used for finding |
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the optimal architecture |
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outputpath : str, optional |
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243
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File location to store the model results |
|
244
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model_path: str, optional |
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245
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Directory to save the models as HDF5 files |
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246
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metric: str, optional |
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247
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metric that is used to evaluate the model on the validation set. |
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248
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See https://keras.io/metrics/ for possible metrics |
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249
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**kwargs: key-value parameters |
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250
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parameters for generating the models |
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251
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(see docstring for modelgen.generate_models) |
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252
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253
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Returns |
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254
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---------- |
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255
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best_model : Keras model |
|
256
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Best performing model, already trained on a small sample data set. |
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257
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best_params : dict |
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258
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Dictionary containing the hyperparameters for the best model |
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259
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best_model_type : str |
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260
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Type of the best model |
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261
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knn_acc : float |
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262
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accuaracy for kNN prediction on validation set |
|
263
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""" |
|
264
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1 |
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models = modelgen.generate_models(X_train.shape, y_train.shape[1], |
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265
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|
|
number_of_models=number_of_models, |
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266
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|
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metrics=[metric], |
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267
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**kwargs) |
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268
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1 |
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histories, val_accuracies, val_losses = train_models_on_samples(X_train, |
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269
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y_train, |
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270
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X_val, |
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271
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y_val, |
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272
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models, |
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273
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nr_epochs, |
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274
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subset_size=subset_size, |
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275
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verbose=verbose, |
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276
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outputfile=outputpath, |
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277
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model_path=model_path, |
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278
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metric=metric, |
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279
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use_noodles=use_noodles) |
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280
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1 |
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best_model_index = np.argmax(val_accuracies) |
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281
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1 |
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best_model, best_params, best_model_type = models[best_model_index] |
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282
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1 |
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knn_acc = kNN_accuracy( |
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283
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|
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X_train[:subset_size, :, :], y_train[:subset_size, :], X_val, y_val) |
|
284
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1 |
|
if verbose: |
|
285
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|
|
print('Best model: model ', best_model_index) |
|
286
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|
|
print('Model type: ', best_model_type) |
|
287
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|
|
print('Hyperparameters: ', best_params) |
|
288
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|
|
print(str(metric) + ' on validation set: ', |
|
289
|
|
|
val_accuracies[best_model_index]) |
|
290
|
|
|
print('Accuracy of kNN on validation set', knn_acc) |
|
291
|
|
|
|
|
292
|
1 |
|
if val_accuracies[best_model_index] < knn_acc: |
|
293
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|
|
warnings.warn('Best model not better than kNN: ' + |
|
294
|
|
|
str(val_accuracies[best_model_index]) + ' vs ' + |
|
295
|
|
|
str(knn_acc) |
|
296
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|
|
) |
|
297
|
1 |
|
return best_model, best_params, best_model_type, knn_acc |
|
298
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|
|
|
299
|
|
|
|
|
300
|
1 |
|
def get_metric_name(name): |
|
301
|
|
|
""" |
|
302
|
|
|
Gives the keras name for a metric |
|
303
|
|
|
|
|
304
|
|
|
Parameters |
|
305
|
|
|
---------- |
|
306
|
|
|
name : str |
|
307
|
|
|
original name of the metric |
|
308
|
|
|
Returns |
|
309
|
|
|
------- |
|
310
|
|
|
|
|
311
|
|
|
""" |
|
312
|
1 |
|
if name == 'acc' or name == 'accuracy': |
|
313
|
1 |
|
return 'acc' |
|
314
|
1 |
|
try: |
|
315
|
1 |
|
metric_fn = metrics.get(name) |
|
316
|
1 |
|
return metric_fn.__name__ |
|
317
|
|
|
except: |
|
318
|
|
|
pass |
|
319
|
|
|
return name |
|
320
|
|
|
|
|
321
|
|
|
|
|
322
|
1 |
|
def kNN_accuracy(X_train, y_train, X_val, y_val, k=1): |
|
323
|
|
|
""" |
|
324
|
|
|
Performs k-Neigherst Neighbors and returns the accuracy score. |
|
325
|
|
|
|
|
326
|
|
|
Parameters |
|
327
|
|
|
---------- |
|
328
|
|
|
X_train : numpy array |
|
329
|
|
|
Train set of shape (num_samples, num_timesteps, num_channels) |
|
330
|
|
|
y_train : numpy array |
|
331
|
|
|
Class labels for train set |
|
332
|
|
|
X_val : numpy array |
|
333
|
|
|
Validation set of shape (num_samples, num_timesteps, num_channels) |
|
334
|
|
|
y_val : numpy array |
|
335
|
|
|
Class labels for validation set |
|
336
|
|
|
k : int |
|
337
|
|
|
number of neighbors to use for classifying |
|
338
|
|
|
|
|
339
|
|
|
Returns |
|
340
|
|
|
------- |
|
341
|
|
|
accuracy: float |
|
342
|
|
|
accuracy score on the validation set |
|
343
|
|
|
""" |
|
344
|
1 |
|
num_samples, num_timesteps, num_channels = X_train.shape |
|
345
|
1 |
|
clf = neighbors.KNeighborsClassifier(k) |
|
346
|
1 |
|
clf.fit( |
|
347
|
|
|
X_train.reshape( |
|
348
|
|
|
num_samples, |
|
349
|
|
|
num_timesteps * |
|
350
|
|
|
num_channels), |
|
351
|
|
|
y_train) |
|
352
|
1 |
|
num_samples, num_timesteps, num_channels = X_val.shape |
|
353
|
1 |
|
val_predict = clf.predict( |
|
354
|
|
|
X_val.reshape(num_samples, |
|
355
|
|
|
num_timesteps * num_channels)) |
|
356
|
|
|
return sklearnmetrics.accuracy_score(val_predict, y_val) |
|
357
|
|
|
|
This check looks for lines that are too long. You can specify the maximum line length.