def test_ais():
"""
Test ais computation by comparing the output of estimate_likelihood to
Russ's code's output for the same parameters.
"""
try:
trainset = MNIST(which_set='train')
testset = MNIST(which_set='test')
except NoDataPathError:
raise SkipTest("PYLEARN2_DATA_PATH environment variable not defined")
nvis = 784
nhid = 20
# Random initialization of RBM parameters
numpy.random.seed(98734)
w_hid = 10 * numpy.cast[theano.config.floatX](numpy.random.randn(nvis,
nhid))
b_vis = 10 * numpy.cast[theano.config.floatX](numpy.random.randn(nvis))
b_hid = 10 * numpy.cast[theano.config.floatX](numpy.random.randn(nhid))
# Initialization of RBM
visible_layer = BinaryVector(nvis)
hidden_layer = BinaryVectorMaxPool(detector_layer_dim=nhid, pool_size=1,
layer_name='h', irange=0.1)
rbm = DBM(100, visible_layer, [hidden_layer], 1)
rbm.visible_layer.set_biases(b_vis)
rbm.hidden_layers[0].set_weights(w_hid)
rbm.hidden_layers[0].set_biases(b_hid)
rbm.nvis = nvis
rbm.nhid = nhid
# Compute real logz and associated train_ll and test_ll using rbm_tools
v_sample = T.matrix('v_sample')
h_sample = T.matrix('h_sample')
W = theano.shared(rbm.hidden_layers[0].get_weights())
hbias = theano.shared(rbm.hidden_layers[0].get_biases())
vbias = theano.shared(rbm.visible_layer.get_biases())
wx_b = T.dot(v_sample, W) + hbias
vbias_term = T.dot(v_sample, vbias)
hidden_term = T.sum(T.log(1 + T.exp(wx_b)), axis=1)
free_energy_v = -hidden_term - vbias_term
free_energy_v_fn = theano.function(inputs=[v_sample],
outputs=free_energy_v)
wh_c = T.dot(h_sample, W.T) + vbias
hbias_term = T.dot(h_sample, hbias)
visible_term = T.sum(T.log(1 + T.exp(wh_c)), axis=1)
free_energy_h = -visible_term - hbias_term
free_energy_h_fn = theano.function(inputs=[h_sample],
outputs=free_energy_h)
real_logz = rbm_tools.compute_log_z(rbm, free_energy_h_fn)
real_ais_train_ll = -rbm_tools.compute_nll(rbm,
trainset.get_design_matrix(),
real_logz, free_energy_v_fn)
real_ais_test_ll = -rbm_tools.compute_nll(rbm, testset.get_design_matrix(),
real_logz, free_energy_v_fn)
# Compute train_ll, test_ll and logz using dbm_metrics
train_ll, test_ll, logz = dbm_metrics.estimate_likelihood([W],
[vbias, hbias],
trainset,
testset,
pos_mf_steps=100)
assert (real_logz - logz) < 2.0
assert (real_ais_train_ll - train_ll) < 2.0
assert (real_ais_test_ll - test_ll) < 2.0
def test_ais():
"""
Test ais computation by comparing the output of estimate_likelihood to
Russ's code's output for the same parameters.
"""
try:
# TODO: the one_hot=True is only necessary because one_hot=False is
# broken, remove it after one_hot=False is fixed.
trainset = MNIST(which_set='train', one_hot=True)
testset = MNIST(which_set='test', one_hot=True)
except NoDataPathError:
raise SkipTest("PYLEARN2_DATA_PATH environment variable not defined")
nvis = 784
nhid = 20
# Random initialization of RBM parameters
numpy.random.seed(98734)
w_hid = 10 * numpy.cast[theano.config.floatX](numpy.random.randn(
nvis, nhid))
b_vis = 10 * numpy.cast[theano.config.floatX](numpy.random.randn(nvis))
b_hid = 10 * numpy.cast[theano.config.floatX](numpy.random.randn(nhid))
# Initialization of RBM
visible_layer = BinaryVector(nvis)
hidden_layer = BinaryVectorMaxPool(detector_layer_dim=nhid,
pool_size=1,
layer_name='h',
irange=0.1)
rbm = DBM(100, visible_layer, [hidden_layer], 1)
rbm.visible_layer.set_biases(b_vis)
rbm.hidden_layers[0].set_weights(w_hid)
rbm.hidden_layers[0].set_biases(b_hid)
rbm.nvis = nvis
rbm.nhid = nhid
# Compute real logz and associated train_ll and test_ll using rbm_tools
v_sample = T.matrix('v_sample')
h_sample = T.matrix('h_sample')
W = theano.shared(rbm.hidden_layers[0].get_weights())
hbias = theano.shared(rbm.hidden_layers[0].get_biases())
vbias = theano.shared(rbm.visible_layer.get_biases())
wx_b = T.dot(v_sample, W) + hbias
vbias_term = T.dot(v_sample, vbias)
hidden_term = T.sum(T.log(1 + T.exp(wx_b)), axis=1)
free_energy_v = -hidden_term - vbias_term
free_energy_v_fn = theano.function(inputs=[v_sample],
outputs=free_energy_v)
wh_c = T.dot(h_sample, W.T) + vbias
hbias_term = T.dot(h_sample, hbias)
visible_term = T.sum(T.log(1 + T.exp(wh_c)), axis=1)
free_energy_h = -visible_term - hbias_term
free_energy_h_fn = theano.function(inputs=[h_sample],
outputs=free_energy_h)
real_logz = rbm_tools.compute_log_z(rbm, free_energy_h_fn)
real_ais_train_ll = -rbm_tools.compute_nll(
rbm, trainset.get_design_matrix(), real_logz, free_energy_v_fn)
real_ais_test_ll = -rbm_tools.compute_nll(rbm, testset.get_design_matrix(),
real_logz, free_energy_v_fn)
# Compute train_ll, test_ll and logz using dbm_metrics
train_ll, test_ll, logz = dbm_metrics.estimate_likelihood([W],
[vbias, hbias],
trainset,
testset,
pos_mf_steps=100)
assert (real_logz - logz) < 2.0
assert (real_ais_train_ll - train_ll) < 2.0
assert (real_ais_test_ll - test_ll) < 2.0
utils.debug.setdebug()
recon = []
nlls = []
for j in range(0, 401):
avg_rec_error = 0
for i in range(0, 500, 100):
rec_error = train_fn(data[i:i+100])
recon.append(rec_error / 100)
avg_rec_error = (i*avg_rec_error + rec_error) / (i+100)
print "Epoch %d: avg_rec_error = %f" % (j+1, avg_rec_error)
if (j%50)==0:
log_z = compute_log_z(rbm, free_energy_fn)
nll = compute_nll(rbm, data, log_z, free_energy_fn)
nlls.append(nll)
print "Epoch %d: avg_nll = %f" % (j+1, nll)
if not args.no_plot:
import matplotlib.pyplot as plt
plt.subplot(2, 1, 1)
plt.plot(range(len(recon)), recon)
plt.xlim(0, len(recon))
plt.title('Reconstruction error per minibatch')
plt.xlabel('minibatch number')
plt.ylabel('reconstruction error')
plt.subplot(2, 1, 2)
plt.plot(range(0, len(nlls) * 50, 50), nlls, '-d')
plt.xlabel('Epoch')
plt.ylabel('Average nll per data point')
plt.show()
