A customized train_mnist example to measure the performance of extension

train_mnist_logreport.py

#!/usr/bin/env python
import argparse

import chainer
import chainer.functions as F
import chainer.links as L
from chainer import training
from chainer.training import extensions

import numpy as np


# Network definition
class MLP(chainer.Chain):

    def __init__(self, n_units, n_out):
        super(MLP, self).__init__()
        with self.init_scope():
            # the size of the inputs to each layer will be inferred
            self.l1 = L.Linear(None, n_units)  # n_in -> n_units
            self.l2 = L.Linear(None, n_units)  # n_units -> n_units
            self.l3 = L.Linear(None, n_out)  # n_units -> n_out

    def forward(self, x):
        h1 = F.relu(self.l1(x))
        h2 = F.relu(self.l2(h1))
        return self.l3(h2)


def main():
    parser = argparse.ArgumentParser(description='Chainer example: MNIST')
    parser.add_argument('--batchsize', '-b', type=int, default=100,
                        help='Number of images in each mini-batch')
    parser.add_argument('--epoch', '-e', type=int, default=20,
                        help='Number of sweeps over the dataset to train')
    parser.add_argument('--device', '-d', type=str, default='-1',
                        help='Device specifier. Either ChainerX device '
                        'specifier or an integer. If non-negative integer, '
                        'CuPy arrays with specified device id are used. If '
                        'negative integer, NumPy arrays are used')
    parser.add_argument('--out', '-o', default='result',
                        help='Directory to output the result')
    parser.add_argument('--unit', '-u', type=int, default=1000,
                        help='Number of units')
    args = parser.parse_args()

    device = chainer.get_device(args.device)

    print('Device: {}'.format(device))
    print('# unit: {}'.format(args.unit))
    print('# Minibatch-size: {}'.format(args.batchsize))
    print('# epoch: {}'.format(args.epoch))
    print('')

    # Set up a neural network to train
    # Classifier reports softmax cross entropy loss and accuracy at every
    # iteration, which will be used by the PrintReport extension below.
    model = L.Classifier(MLP(args.unit, 10))
    model.to_device(device)
    device.use()

    # Setup an optimizer
    optimizer = chainer.optimizers.Adam()
    optimizer.setup(model)

    # Load the MNIST dataset
    train, _ = chainer.datasets.get_mnist()
    train = chainer.datasets.TupleDataset(
        np.stack([train[0][0]]), np.stack([train[0][1]]))

    train_iter = chainer.iterators.SerialIterator(train, args.batchsize)

    # Set up a trainer
    updater = training.updaters.StandardUpdater(
        train_iter, optimizer, device=device)
    trainer = training.Trainer(updater, (args.epoch, 'epoch'), out=args.out)

    # Write a log of evaluation statistics for each epoch
    trainer.extend(extensions.LogReport())

    # Run the training
    trainer.run()


if __name__ == '__main__':
    main()