gistfile1.py

import theano
from pylearn2.models import mlp
from pylearn2.training_algorithms import sgd
from pylearn2.termination_criteria import EpochCounter
from pylearn2.datasets.dense_design_matrix import DenseDesignMatrix
import numpy as np
from random import randint


class XOR(DenseDesignMatrix):
    def __init__(self):
        self.class_names = ['0', '1']
        X = [[randint(0, 1), randint(0, 1)] for _ in range(1000)]
        y = []
        for a, b in X:
            if a + b == 1:
                y.append([0, 1])
            else:
                y.append([1, 0])
        X = np.array(X)
        y = np.array(y)
        super(XOR, self).__init__(X=X, y=y)


# create XOR dataset
ds = XOR()
# create hidden layer with 2 nodes, init weights in range -0.1 to 0.1 and add
# a bias with value 1
hidden_layer = mlp.Sigmoid(layer_name='hidden', dim=2, irange=.1, init_bias=1.)
# create Softmax output layer
output_layer = mlp.Softmax(2, 'output', irange=.1)
# create Stochastic Gradient Descent trainer that runs for 400 epochs
trainer = sgd.SGD(learning_rate=.05, batch_size=10, termination_criterion=EpochCounter(400))
layers = [hidden_layer, output_layer]
# create neural net that takes two inputs
ann = mlp.MLP(layers, nvis=2)
trainer.setup(ann, ds)
# train neural net until the termination criterion is true
while True:
    trainer.train(dataset=ds)
    ann.monitor.report_epoch()
    ann.monitor()
    if not trainer.continue_learning(ann):
        break

inputs = np.array([[0, 0]])
print ann.fprop(theano.shared(inputs, name='inputs')).eval()
inputs = np.array([[0, 1]])
print ann.fprop(theano.shared(inputs, name='inputs')).eval()
inputs = np.array([[1, 0]])
print ann.fprop(theano.shared(inputs, name='inputs')).eval()
inputs = np.array([[1, 1]])
print ann.fprop(theano.shared(inputs, name='inputs')).eval()

I wish pylearn2 dev could have similar tutorials to this.