Tag Archives: optimization

Perform optimization with Nkululeko

Here's one idea how to find the optimal values for 2 layers of an MLP net with nkululeko:

  • store your meta-parameters in arrays
  • loop over them and initialize an experiment each time
  • keep the experiment name but change your parameters and the plot name
  • this way you can re-use your extracted features and do not get your harddisk cluttered.

Here's some python code to illustrate this idea:

def main(config_file):
    # load one configuration per experiment
    config = configparser.ConfigParser()
    config.read(config_file)
    util = Util()
    l1s = [32, 64, 128]
    l2s = [16, 32, 64]
    for l1 in l1s:
        for l2 in l2s:
            # create a new experiment
            expr = exp.Experiment(config)

            plotname = f'{util.get_exp_name()}_{l1}_{l2}'
            util.set_config_val('PLOT', 'name', plotname)

            print(f'running {expr.name} with layers {l1} and {l2}')

            layers = {'l1':l1, 'l2':l2}
            util.set_config_val('MODEL', 'layers', layers)

            # load the data
            expr.load_datasets()

            # split into train and test
            expr.fill_train_and_tests()
            util.debug(f'train shape : {expr.df_train.shape}, test shape:{expr.df_test.shape}')

            # extract features
            expr.extract_feats()
            util.debug(f'train feats shape : {expr.feats_train.df.shape}, test feats shape:{expr.feats_test.df.shape}')

            # initialize a run manager
            expr.init_runmanager()

            # run the experiment
            expr.run()

    print('DONE')

Keep in mind though that meta parameter optimization like done here is in itself a learning problem. It is usually not feasible to systematically try out all combinations of possible values and thus some kind of stochastic aproach is preferable.