def extract(images):
data = []
for i in range(images.shape[0]):
data.append(
generate_data_from_image(images[i], input_mask, output_mask))
inputs, outputs = zip(*data)
return hstack(inputs), hstack(outputs)
def train_model(img, input_mask, output_mask):
# generate data
inputs, outputs = generate_data_from_image(img, input_mask, output_mask,
120000)
# split data into training and validation sets
data_train = inputs[:, :100000], outputs[:, :100000]
data_valid = inputs[:, 100000:], outputs[:, 100000:]
# compute normalizing transformation
pre = WhiteningPreconditioner(*data_train)
# intialize model
model = MCGSM(dim_in=data_train[0].shape[0],
dim_out=data_train[1].shape[0],
num_components=8,
num_scales=4,
num_features=30)
# fit parameters
model.initialize(*pre(*data_train))
model.train(*chain(pre(*data_train), pre(*data_valid)),
parameters={
'verbosity': 1,
'max_iter': 1000,
'threshold': 1e-7,
'val_iter': 5,
'val_look_ahead': 10,
'num_grad': 20,
})
return model, pre
def train_model(img, input_mask, output_mask):
# generate data
inputs, outputs = generate_data_from_image(
img, input_mask, output_mask, 120000)
# split data into training and validation sets
data_train = inputs[:, :100000], outputs[:, :100000]
data_valid = inputs[:, 100000:], outputs[:, 100000:]
# compute normalizing transformation
pre = WhiteningPreconditioner(*data_train)
# intialize model
model = MCGSM(
dim_in=data_train[0].shape[0],
dim_out=data_train[1].shape[0],
num_components=8,
num_scales=4,
num_features=30)
# fit parameters
model.initialize(*pre(*data_train))
model.train(*chain(pre(*data_train), pre(*data_valid)),
parameters={
'verbosity': 1,
'max_iter': 1000,
'threshold': 1e-7,
'val_iter': 5,
'val_look_ahead': 10,
'num_grad': 20,
})
return model, pre
def main(argv):
# load image and turn into grayscale
img = rgb2gray(imread('media/newyork.png'))
# generate data
inputs, outputs = generate_data_from_image(
img, input_mask, output_mask, 220000)
# split data into training, test, and validation sets
inputs = split(inputs, [100000, 200000], 1)
outputs = split(outputs, [100000, 200000], 1)
data_train = inputs[0], outputs[0]
data_test = inputs[1], outputs[1]
data_valid = inputs[2], outputs[2]
# compute normalizing transformation
pre = WhiteningPreconditioner(*data_train)
# intialize model
model = MCGSM(
dim_in=data_train[0].shape[0],
dim_out=data_train[1].shape[0],
num_components=8,
num_scales=4,
num_features=32)
# fit parameters
model.initialize(*pre(*data_train))
model.train(*chain(pre(*data_train), pre(*data_valid)),
parameters={
'verbosity': 1,
'max_iter': 1000,
'threshold': 1e-7,
'val_iter': 5,
'val_look_ahead': 10,
'num_grad': 20,
})
# evaluate model
print 'Average log-likelihood: {0:.4f} [bit/px]'.format(
-model.evaluate(data_test[0], data_test[1], pre))
# synthesize a new image
img_sample = sample_image(img, model, input_mask, output_mask, pre)
imwrite('newyork_sample.png', img_sample,
cmap='gray',
vmin=min(img),
vmax=max(img))
# save model
with open('image_model.pck', 'wb') as handle:
dump({
'model': model,
'input_mask': input_mask,
'output_mask': output_mask}, handle, 1)
return 0
def process(image):
inputs, outputs = generate_data_from_image(image, self.input_mask,
self.output_mask)
inputs = asarray(inputs.T.reshape(
image.shape[0] - self.input_mask.shape[0] + 1,
image.shape[1] - self.input_mask.shape[1] + 1, -1),
dtype='float32')
outputs = asarray(outputs.T.reshape(
image.shape[0] - self.input_mask.shape[0] + 1,
image.shape[1] - self.input_mask.shape[1] + 1, -1),
dtype='float32')
return inputs, outputs
def process(image): inputs, outputs = generate_data_from_image( image, self.input_mask, self.output_mask) inputs = asarray( inputs.T.reshape( image.shape[0] - self.input_mask.shape[0] + 1, image.shape[1] - self.input_mask.shape[1] + 1, -1), dtype='float32') outputs = asarray( outputs.T.reshape( image.shape[0] - self.input_mask.shape[0] + 1, image.shape[1] - self.input_mask.shape[1] + 1, -1), dtype='float32') return inputs, outputs
def main(argv):
parser = ArgumentParser(argv[0], description=__doc__)
parser.add_argument('model', type=str)
parser.add_argument('--num_data', '-N', type=int, default=5000000)
parser.add_argument('--data',
'-d',
type=str,
default='data/vanhateren_deq2_test.mat')
parser.add_argument('--verbosity', '-v', type=int, default=1)
args = parser.parse_args(argv[1:])
### LOAD RESULTS
experiment = Experiment(args.model)
### DATA HANDLING
if args.verbosity > 0:
print 'Loading data...'
# load data
images = loadmat(args.data)['data']
# causal neighborhood definition
input_mask = experiment['input_mask']
output_mask = experiment['output_mask']
# extract causal neighborhoods
num_samples = args.num_data // images.shape[0]
data = []
for i in range(images.shape[0]):
data.append(
generate_data_from_image(images[i], input_mask, output_mask,
num_samples))
inputs, outputs = zip(*data)
inputs = hstack(inputs)
outputs = hstack(outputs)
### MODEL EVALUATION
crossentropy = experiment['model'].evaluate(inputs, outputs,
experiment['preconditioner'])
print 'Cross-entropy: {0:.4f} [bit/px]'.format(crossentropy)
return 0
def main(argv):
parser = ArgumentParser(argv[0], description=__doc__)
parser.add_argument('model', type=str)
parser.add_argument('--num_data', '-N', type=int, default=5000000)
parser.add_argument('--data', '-d', type=str, default='data/vanhateren_deq2_test.mat')
parser.add_argument('--verbosity', '-v', type=int, default=1)
args = parser.parse_args(argv[1:])
### LOAD RESULTS
experiment = Experiment(args.model)
### DATA HANDLING
if args.verbosity > 0:
print 'Loading data...'
# load data
images = loadmat(args.data)['data']
# causal neighborhood definition
input_mask = experiment['input_mask']
output_mask = experiment['output_mask']
# extract causal neighborhoods
num_samples = args.num_data // images.shape[0]
data = []
for i in range(images.shape[0]):
data.append(generate_data_from_image(
images[i], input_mask, output_mask, num_samples))
inputs, outputs = zip(*data)
inputs = hstack(inputs)
outputs = hstack(outputs)
### MODEL EVALUATION
crossentropy = experiment['model'].evaluate(inputs, outputs, experiment['preconditioner'])
print 'Cross-entropy: {0:.4f} [bit/px]'.format(crossentropy)
return 0
def extract(image): patches = generate_data_from_image(image, input_mask, output_mask, num_samples_per_image)[0] return patches
def main(argv):
# load image and turn into grayscale
img = rgb2gray(imread('media/newyork.png'))
# generate data
inputs, outputs = generate_data_from_image(img, input_mask, output_mask,
220000)
# split data into training, test, and validation sets
inputs = split(inputs, [100000, 200000], 1)
outputs = split(outputs, [100000, 200000], 1)
data_train = inputs[0], outputs[0]
data_test = inputs[1], outputs[1]
data_valid = inputs[2], outputs[2]
# compute normalizing transformation
pre = WhiteningPreconditioner(*data_train)
# intialize model
model = MCGSM(dim_in=data_train[0].shape[0],
dim_out=data_train[1].shape[0],
num_components=8,
num_scales=4,
num_features=32)
# fit parameters
model.initialize(*pre(*data_train))
model.train(*chain(pre(*data_train), pre(*data_valid)),
parameters={
'verbosity': 1,
'max_iter': 1000,
'threshold': 1e-7,
'val_iter': 5,
'val_look_ahead': 10,
'num_grad': 20,
})
# evaluate model
print 'Average log-likelihood: {0:.4f} [bit/px]'.format(
-model.evaluate(data_test[0], data_test[1], pre))
# synthesize a new image
img_sample = sample_image(img, model, input_mask, output_mask, pre)
imwrite('newyork_sample.png',
img_sample,
cmap='gray',
vmin=min(img),
vmax=max(img))
# save model
with open('image_model.pck', 'wb') as handle:
dump(
{
'model': model,
'input_mask': input_mask,
'output_mask': output_mask
}, handle, 1)
return 0
def sample(self, images, min_values=None, max_values=None):
"""
Sample one or several images.
@type images: C{ndarray}
@param images: an array or a list of images to initialize pixels at boundaries
"""
if min_values is not None:
min_values = asarray(min_values).reshape(1, 1, 1, -1)
if max_values is not None:
max_values = asarray(max_values).reshape(1, 1, 1, -1)
# reshape images into four-dimensional arrays
shape = images.shape
if images.ndim == 2:
images = images[None, :, :, None]
elif images.ndim == 3:
if self.num_channels > 1:
images = images[None]
else:
images = images[:, :, :, None]
# create spatial LSTMs for sampling
slstm = []
for l in range(self.num_layers):
slstm.append(
SLSTM(num_rows=1,
num_cols=1,
num_channels=sum(self.input_mask)
if l < 1 else self.num_hiddens,
num_hiddens=self.num_hiddens,
batch_size=images.shape[0],
nonlinearity=self.nonlinearity,
extended=self.extended,
slstm=self.slstm[l],
verbosity=self.verbosity))
# container for hidden and memory unit activations
hiddens = []
memory = []
for l in range(self.num_layers):
hiddens.append(defaultdict(lambda: 0.))
memory.append(defaultdict(lambda: 0.))
# locate output pixel
for i_off, j_off in zip(range(self.output_mask.shape[0]),
range(self.output_mask.shape[1])):
if any(self.output_mask[i_off, j_off]):
break
for i in range(images.shape[1] - self.input_mask.shape[0] + 1):
for j in range(images.shape[2] - self.input_mask.shape[1] + 1):
# extract patches from images
patches = images[:, i:i + self.input_mask.shape[0],
j:j + self.input_mask.shape[1]]
# extract causal neighborhoods from patches
inputs = []
for k in range(images.shape[0]):
inputs.append(
generate_data_from_image(patches[k, :, :],
self.input_mask,
self.output_mask)[0])
inputs = asarray(inputs)
inputs = inputs.reshape(inputs.shape[0], 1, 1, -1)
if self.preconditioner:
inputs = self._precondition(inputs)
# set hidden unit activations
for l in range(self.num_layers):
slstm[l].net.blobs['h_init_i_jm1'].data[:] = hiddens[l][i,
j -
1]
slstm[l].net.blobs['h_init_im1_j'].data[:] = hiddens[l][i -
1,
j]
slstm[l].net.blobs['c_init_i_jm1'].data[:] = memory[l][i,
j -
1]
slstm[l].net.blobs['c_init_im1_j'].data[:] = memory[l][i -
1,
j]
# compute hidden unit activations
activations = inputs
for l in range(self.num_layers):
activations = slstm[l].forward(activations)
# store hidden unit activations
for l in range(self.num_layers):
hiddens[l][i,
j] = slstm[l].net.blobs['outputs'].data.copy()
memory[l][i, j] = slstm[l].net.blobs['c_0_0'].data.copy()
for _ in range(10):
# sample MCGSM
outputs = self.mcgsm.sample(hiddens[-1][i, j].reshape(
-1, self.num_hiddens).T)
outputs = outputs.T.reshape(outputs.shape[1], 1, 1,
outputs.shape[0])
if not any(isnan(outputs)):
break
print 'Warning: NaNs detected.'
if self.preconditioner:
inputs, outputs = self._precondition_inverse(
inputs, outputs)
if max_values is not None:
outputs[outputs > max_values] = max_values[
outputs > max_values]
if min_values is not None:
outputs[outputs < min_values] = min_values[
outputs < min_values]
# insert sampled pixels into images
images[:, i + i_off,
j + j_off][self.output_mask[i_off, j_off]] = outputs
return images.reshape(*shape)
def test_generate_data_from_image(self): xmask = asarray([ [1, 1], [1, 0]], dtype='bool') ymask = asarray([ [0, 0], [0, 1]], dtype='bool') img = asarray([ [1., 2.], [3., 4.]]) inputs, outputs = generate_data_from_image(img, xmask, ymask, 1) self.assertLess(max(abs(inputs - [[1.], [2.], [3.]])), 1e-10) self.assertLess(max(abs(outputs - [[4.]])), 1e-10) inputs, outputs = generate_data_from_image(randn(512, 512), xmask, ymask, 100) self.assertEqual(inputs.shape[0], 3) self.assertEqual(inputs.shape[1], 100) self.assertEqual(outputs.shape[0], 1) self.assertEqual(outputs.shape[1], 100) inputs, outputs = generate_data_from_image(randn(512, 512, 2), xmask, ymask, 100) self.assertEqual(inputs.shape[0], 6) self.assertEqual(inputs.shape[1], 100) self.assertEqual(outputs.shape[0], 2) self.assertEqual(outputs.shape[1], 100) # multi-channel masks xmask = dstack([ asarray([ [1, 1], [1, 0]], dtype='bool'), asarray([ [1, 1], [1, 0]], dtype='bool')]) ymask = dstack([ asarray([ [0, 0], [0, 1]], dtype='bool'), asarray([ [0, 0], [0, 1]], dtype='bool')]) inputs, outputs = generate_data_from_image(randn(512, 512, 2), xmask, ymask, 100) self.assertEqual(inputs.shape[0], 6) self.assertEqual(inputs.shape[1], 100) self.assertEqual(outputs.shape[0], 2) self.assertEqual(outputs.shape[1], 100) # invalid masks due to overlap xmask = asarray([ [1, 1], [1, 1]], dtype='bool') ymask = asarray([ [0, 0], [0, 1]], dtype='bool') self.assertRaises(Exception, generate_data_from_image, img, xmask, ymask, 1) # test extracting of xmask = asarray([ [1, 1], [1, 1], [1, 0]], dtype='bool') ymask = asarray([ [0, 0], [0, 0], [0, 1]], dtype='bool') # test extracting of all possible inputs and outputs img = randn(64, 64) inputs, outputs = generate_data_from_image(img, xmask, ymask) # try reconstructing image from outputs self.assertLess(max(abs(outputs.reshape(62, 63, order='C') - img[2:, 1:])), 1e-16) img = randn(64, 64, 3) inputs, outputs = generate_data_from_image(img, xmask, ymask) img_rec = outputs.reshape(3, 62, 63, order='C') img_rec = transpose(img_rec, [1, 2, 0]) self.assertLess(max(abs(img_rec - img[2:, 1:])), 1e-16)
def extract(image):
return generate_data_from_image(image, input_mask, output_mask,
num_samples)
def extract(image):
patches = generate_data_from_image(image, input_mask, output_mask,
num_samples_per_image)[0]
return patches
def sample(self, images, min_values=None, max_values=None):
"""
Sample one or several images.
@type images: C{ndarray}
@param images: an array or a list of images to initialize pixels at boundaries
"""
if min_values is not None:
min_values = asarray(min_values).reshape(1, 1, 1, -1)
if max_values is not None:
max_values = asarray(max_values).reshape(1, 1, 1, -1)
# reshape images into four-dimensional arrays
shape = images.shape
if images.ndim == 2:
images = images[None, :, :, None]
elif images.ndim == 3:
if self.num_channels > 1:
images = images[None]
else:
images = images[:, :, :, None]
# create spatial LSTMs for sampling
slstm = []
for l in range(self.num_layers):
slstm.append(SLSTM(
num_rows=1,
num_cols=1,
num_channels=sum(self.input_mask) if l < 1 else self.num_hiddens,
num_hiddens=self.num_hiddens,
batch_size=images.shape[0],
nonlinearity=self.nonlinearity,
extended=self.extended,
slstm=self.slstm[l],
verbosity=self.verbosity))
# container for hidden and memory unit activations
hiddens = []
memory = []
for l in range(self.num_layers):
hiddens.append(defaultdict(lambda: 0.))
memory.append(defaultdict(lambda: 0.))
# locate output pixel
for i_off, j_off in zip(
range(self.output_mask.shape[0]),
range(self.output_mask.shape[1])):
if any(self.output_mask[i_off, j_off]):
break
for i in range(images.shape[1] - self.input_mask.shape[0] + 1):
for j in range(images.shape[2] - self.input_mask.shape[1] + 1):
# extract patches from images
patches = images[:,
i:i + self.input_mask.shape[0],
j:j + self.input_mask.shape[1]]
# extract causal neighborhoods from patches
inputs = []
for k in range(images.shape[0]):
inputs.append(
generate_data_from_image(
patches[k, :, :], self.input_mask, self.output_mask)[0])
inputs = asarray(inputs)
inputs = inputs.reshape(inputs.shape[0], 1, 1, -1)
if self.preconditioner:
inputs = self._precondition(inputs)
# set hidden unit activations
for l in range(self.num_layers):
slstm[l].net.blobs['h_init_i_jm1'].data[:] = hiddens[l][i, j - 1]
slstm[l].net.blobs['h_init_im1_j'].data[:] = hiddens[l][i - 1, j]
slstm[l].net.blobs['c_init_i_jm1'].data[:] = memory[l][i, j - 1]
slstm[l].net.blobs['c_init_im1_j'].data[:] = memory[l][i - 1, j]
# compute hidden unit activations
activations = inputs
for l in range(self.num_layers):
activations = slstm[l].forward(activations)
# store hidden unit activations
for l in range(self.num_layers):
hiddens[l][i, j] = slstm[l].net.blobs['outputs'].data.copy()
memory[l][i, j] = slstm[l].net.blobs['c_0_0'].data.copy()
for _ in range(10):
# sample MCGSM
outputs = self.mcgsm.sample(
hiddens[-1][i, j].reshape(-1, self.num_hiddens).T)
outputs = outputs.T.reshape(outputs.shape[1], 1, 1, outputs.shape[0])
if not any(isnan(outputs)):
break
print 'Warning: NaNs detected.'
if self.preconditioner:
inputs, outputs = self._precondition_inverse(inputs, outputs)
if max_values is not None:
outputs[outputs > max_values] = max_values[outputs > max_values]
if min_values is not None:
outputs[outputs < min_values] = min_values[outputs < min_values]
# insert sampled pixels into images
images[:, i + i_off, j + j_off][self.output_mask[i_off, j_off]] = outputs
return images.reshape(*shape)
def extract(image): return generate_data_from_image( image, input_mask, output_mask, num_samples)
def test_generate_data_from_image(self):
xmask = asarray([[1, 1], [1, 0]], dtype='bool')
ymask = asarray([[0, 0], [0, 1]], dtype='bool')
img = asarray([[1., 2.], [3., 4.]])
inputs, outputs = generate_data_from_image(img, xmask, ymask, 1)
self.assertLess(max(abs(inputs - [[1.], [2.], [3.]])), 1e-10)
self.assertLess(max(abs(outputs - [[4.]])), 1e-10)
inputs, outputs = generate_data_from_image(randn(512, 512), xmask,
ymask, 100)
self.assertEqual(inputs.shape[0], 3)
self.assertEqual(inputs.shape[1], 100)
self.assertEqual(outputs.shape[0], 1)
self.assertEqual(outputs.shape[1], 100)
inputs, outputs = generate_data_from_image(randn(512, 512, 2), xmask,
ymask, 100)
self.assertEqual(inputs.shape[0], 6)
self.assertEqual(inputs.shape[1], 100)
self.assertEqual(outputs.shape[0], 2)
self.assertEqual(outputs.shape[1], 100)
# multi-channel masks
xmask = dstack([
asarray([[1, 1], [1, 0]], dtype='bool'),
asarray([[1, 1], [1, 0]], dtype='bool')
])
ymask = dstack([
asarray([[0, 0], [0, 1]], dtype='bool'),
asarray([[0, 0], [0, 1]], dtype='bool')
])
inputs, outputs = generate_data_from_image(randn(512, 512, 2), xmask,
ymask, 100)
self.assertEqual(inputs.shape[0], 6)
self.assertEqual(inputs.shape[1], 100)
self.assertEqual(outputs.shape[0], 2)
self.assertEqual(outputs.shape[1], 100)
# invalid masks due to overlap
xmask = asarray([[1, 1], [1, 1]], dtype='bool')
ymask = asarray([[0, 0], [0, 1]], dtype='bool')
self.assertRaises(Exception, generate_data_from_image, img, xmask,
ymask, 1)
# test extracting of
xmask = asarray([[1, 1], [1, 1], [1, 0]], dtype='bool')
ymask = asarray([[0, 0], [0, 0], [0, 1]], dtype='bool')
# test extracting of all possible inputs and outputs
img = randn(64, 64)
inputs, outputs = generate_data_from_image(img, xmask, ymask)
# try reconstructing image from outputs
self.assertLess(
max(abs(outputs.reshape(62, 63, order='C') - img[2:, 1:])), 1e-16)
img = randn(64, 64, 3)
inputs, outputs = generate_data_from_image(img, xmask, ymask)
img_rec = outputs.reshape(3, 62, 63, order='C')
img_rec = transpose(img_rec, [1, 2, 0])
self.assertLess(max(abs(img_rec - img[2:, 1:])), 1e-16)
def sample(self,
images,
min_values=None,
max_values=None,
mask=None,
return_loglik=False):
"""
Sample one or several images.
@type images: C{ndarray}/C{list}
@param images: an array or a list of images to initialize pixels at boundaries
@type min_values: C{ndarray}/C{list}
@param min_values: list of lower bounds for each channel (for increased stability)
@type max_values: C{ndarray}/C{list}
@param max_values: list of upper bounds for each channel (for increased stability)
@type mask: C{ndarray}
@param mask: replace only certain pixels indicated by this Boolean mask
@rtype: C{ndarray}
@return: sampled images of the size of the images given as input
"""
# reshape images into four-dimensional arrays
shape = images.shape
if images.ndim == 2:
images = images[None, :, :, None]
elif images.ndim == 3:
if self.num_channels > 1:
images = images[None]
else:
images = images[:, :, :, None]
# create spatial LSTMs for sampling
for l in range(self.num_layers):
if self.slstm[l].num_rows != 1 \
or self.slstm[l].num_cols != 1 \
or self.slstm[l].batch_size != images.shape[0]:
self.slstm[l] = SLSTM(num_rows=1,
num_cols=1,
num_channels=sum(self.input_mask)
if l < 1 else self.num_hiddens,
num_hiddens=self.num_hiddens,
batch_size=images.shape[0],
nonlinearity=self.nonlinearity,
slstm=self.slstm[l],
extended=self.extended)
# container for hidden and memory unit activations
hiddens = []
memory = []
for l in range(self.num_layers):
hiddens.append(defaultdict(lambda: 0.))
memory.append(defaultdict(lambda: 0.))
# locate output pixel
for i_off, j_off in zip(range(self.output_mask.shape[0]),
range(self.output_mask.shape[1])):
if any(self.output_mask[i_off, j_off]):
break
if min_values is not None:
min_values = asarray(min_values).reshape(1, 1, 1, -1)
if self.output_mask.ndim > 2:
min_values = min_values[:, :, :, self.output_mask[i_off,
j_off]]
if max_values is not None:
max_values = asarray(max_values).reshape(1, 1, 1, -1)
if self.output_mask.ndim > 2:
max_values = max_values[:, :, :, self.output_mask[i_off,
j_off]]
# unnormalized log-density of generated sample
logq = 0.
for i in range(images.shape[1] - self.input_mask.shape[0] + 1):
for j in range(images.shape[2] - self.input_mask.shape[1] + 1):
# extract patches from images
patches = images[:, i:i + self.input_mask.shape[0],
j:j + self.input_mask.shape[1]]
# extract causal neighborhoods from patches
inputs = []
for k in range(images.shape[0]):
inputs.append(
generate_data_from_image(patches[k, :, :],
self.input_mask,
self.output_mask)[0])
inputs = asarray(inputs)
inputs = inputs.reshape(inputs.shape[0], 1, 1, -1)
if self.preconditioner:
inputs = self._precondition(inputs)
# set hidden unit activations
for l in range(self.num_layers):
self.slstm[l].net.blobs['h_init_i_jm1'].data[:] = hiddens[
l][i, j - 1]
self.slstm[l].net.blobs['h_init_im1_j'].data[:] = hiddens[
l][i - 1, j]
self.slstm[l].net.blobs['c_init_i_jm1'].data[:] = memory[
l][i, j - 1]
self.slstm[l].net.blobs['c_init_im1_j'].data[:] = memory[
l][i - 1, j]
# compute hidden unit activations
activations = inputs
for l in range(self.num_layers):
activations = self.slstm[l].forward(activations)
# store hidden unit activations
for l in range(self.num_layers):
hiddens[l][
i, j] = self.slstm[l].net.blobs['outputs'].data.copy()
memory[l][
i, j] = self.slstm[l].net.blobs['c_0_0'].data.copy()
if mask is not None and not mask[i + i_off, j + j_off]:
# skip sampling of this pixel
continue
for _ in range(10):
# sample MCGSM
outputs = self.mcgsm.sample(hiddens[-1][i, j].reshape(
-1, self.num_hiddens).T)
if not any(isnan(outputs)):
break
print 'Warning: NaNs detected.'
if return_loglik:
logq += self.mcgsm.loglikelihood(
hiddens[-1][i, j].reshape(-1, self.num_hiddens).T,
outputs)
outputs = outputs.T.reshape(outputs.shape[1], 1, 1,
outputs.shape[0])
if self.preconditioner:
inputs, outputs = self._precondition_inverse(
inputs, outputs)
if max_values is not None:
outputs[outputs > max_values] = max_values[
outputs > max_values]
if min_values is not None:
outputs[outputs < min_values] = min_values[
outputs < min_values]
# insert sampled pixels into images
if self.output_mask.ndim > 2:
images[:, i + i_off,
j + j_off][:, self.output_mask[i_off,
j_off]] = outputs
else:
images[:, i + i_off, j + j_off] = outputs
images = images.reshape(*shape)
if return_loglik:
return images, logq
return images
def sample(self, images, min_values=None, max_values=None, mask=None, return_loglik=False):
"""
Sample one or several images.
@type images: C{ndarray}/C{list}
@param images: an array or a list of images to initialize pixels at boundaries
@type min_values: C{ndarray}/C{list}
@param min_values: list of lower bounds for each channel (for increased stability)
@type max_values: C{ndarray}/C{list}
@param max_values: list of upper bounds for each channel (for increased stability)
@type mask: C{ndarray}
@param mask: replace only certain pixels indicated by this Boolean mask
@rtype: C{ndarray}
@return: sampled images of the size of the images given as input
"""
# reshape images into four-dimensional arrays
shape = images.shape
if images.ndim == 2:
images = images[None, :, :, None]
elif images.ndim == 3:
if self.num_channels > 1:
images = images[None]
else:
images = images[:, :, :, None]
# create spatial LSTMs for sampling
for l in range(self.num_layers):
if (
self.slstm[l].num_rows != 1
or self.slstm[l].num_cols != 1
or self.slstm[l].batch_size != images.shape[0]
):
self.slstm[l] = SLSTM(
num_rows=1,
num_cols=1,
num_channels=sum(self.input_mask) if l < 1 else self.num_hiddens,
num_hiddens=self.num_hiddens,
batch_size=images.shape[0],
nonlinearity=self.nonlinearity,
slstm=self.slstm[l],
extended=self.extended,
)
# container for hidden and memory unit activations
hiddens = []
memory = []
for l in range(self.num_layers):
hiddens.append(defaultdict(lambda: 0.0))
memory.append(defaultdict(lambda: 0.0))
# locate output pixel
for i_off, j_off in zip(range(self.output_mask.shape[0]), range(self.output_mask.shape[1])):
if any(self.output_mask[i_off, j_off]):
break
if min_values is not None:
min_values = asarray(min_values).reshape(1, 1, 1, -1)
if self.output_mask.ndim > 2:
min_values = min_values[:, :, :, self.output_mask[i_off, j_off]]
if max_values is not None:
max_values = asarray(max_values).reshape(1, 1, 1, -1)
if self.output_mask.ndim > 2:
max_values = max_values[:, :, :, self.output_mask[i_off, j_off]]
# unnormalized log-density of generated sample
logq = 0.0
for i in range(images.shape[1] - self.input_mask.shape[0] + 1):
for j in range(images.shape[2] - self.input_mask.shape[1] + 1):
# extract patches from images
patches = images[:, i : i + self.input_mask.shape[0], j : j + self.input_mask.shape[1]]
# extract causal neighborhoods from patches
inputs = []
for k in range(images.shape[0]):
inputs.append(generate_data_from_image(patches[k, :, :], self.input_mask, self.output_mask)[0])
inputs = asarray(inputs)
inputs = inputs.reshape(inputs.shape[0], 1, 1, -1)
if self.preconditioner:
inputs = self._precondition(inputs)
# set hidden unit activations
for l in range(self.num_layers):
self.slstm[l].net.blobs["h_init_i_jm1"].data[:] = hiddens[l][i, j - 1]
self.slstm[l].net.blobs["h_init_im1_j"].data[:] = hiddens[l][i - 1, j]
self.slstm[l].net.blobs["c_init_i_jm1"].data[:] = memory[l][i, j - 1]
self.slstm[l].net.blobs["c_init_im1_j"].data[:] = memory[l][i - 1, j]
# compute hidden unit activations
activations = inputs
for l in range(self.num_layers):
activations = self.slstm[l].forward(activations)
# store hidden unit activations
for l in range(self.num_layers):
hiddens[l][i, j] = self.slstm[l].net.blobs["outputs"].data.copy()
memory[l][i, j] = self.slstm[l].net.blobs["c_0_0"].data.copy()
if mask is not None and not mask[i + i_off, j + j_off]:
# skip sampling of this pixel
continue
for _ in range(10):
# sample MCGSM
outputs = self.mcgsm.sample(hiddens[-1][i, j].reshape(-1, self.num_hiddens).T)
if not any(isnan(outputs)):
break
print "Warning: NaNs detected."
if return_loglik:
logq += self.mcgsm.loglikelihood(hiddens[-1][i, j].reshape(-1, self.num_hiddens).T, outputs)
outputs = outputs.T.reshape(outputs.shape[1], 1, 1, outputs.shape[0])
if self.preconditioner:
inputs, outputs = self._precondition_inverse(inputs, outputs)
if max_values is not None:
outputs[outputs > max_values] = max_values[outputs > max_values]
if min_values is not None:
outputs[outputs < min_values] = min_values[outputs < min_values]
# insert sampled pixels into images
if self.output_mask.ndim > 2:
images[:, i + i_off, j + j_off][:, self.output_mask[i_off, j_off]] = outputs
else:
images[:, i + i_off, j + j_off] = outputs
images = images.reshape(*shape)
if return_loglik:
return images, logq
return images