def learn_to_move(nprims = 200, nbatch = 50, width = 224, height = 224):
"""Creates a network which takes as input a image and returns a cost.
Network extracts features of image to create shape params which are rendered.
The similarity between the rendered image and the actual image is the cost
"""
assert nbatch % 2 == 0 # Minibatch must be even in size
params_per_prim = 3
nshape_params = nprims * params_per_prim
# Render the input shapes
fragCoords = T.tensor3('fragCoords')
shape_params = T.tensor3("scenes")
res, scan_updates = symbolic_render(nprims, shape_params, fragCoords, width, height)
res_reshape = res.dimshuffle([2,'x',0,1])
# Split batch in half and give each image two channels
res_reshape_split = T.reshape(res_reshape, (nbatch/2, 2, width, height))
# Put the different convnets into two channels
net = {}
net['input'] = InputLayer((nbatch/2, 2, width, height), input_var = res_reshape_split)
net['conv1'] = ConvLayer(net['input'], num_filters=96, filter_size=7, stride=2)
net['norm1'] = NormLayer(net['conv1'], alpha=0.0001) # caffe has alpha = alpha * pool_size
net['pool1'] = PoolLayer(net['norm1'], pool_size=3, stride=3, ignore_border=False)
net['conv2'] = ConvLayer(net['pool1'], num_filters=256, filter_size=5)
net['pool2'] = PoolLayer(net['conv2'], pool_size=2, stride=2, ignore_border=False)
net['conv3'] = ConvLayer(net['pool2'], num_filters=512, filter_size=3, pad=1)
net['conv4'] = ConvLayer(net['conv3'], num_filters=512, filter_size=3, pad=1)
net['conv5'] = ConvLayer(net['conv4'], num_filters=512, filter_size=3, pad=1)
net['pool5'] = PoolLayer(net['conv5'], pool_size=3, stride=3, ignore_border=False)
net['fc6'] = DenseLayer(net['pool5'], num_units=4096)
net['drop6'] = DropoutLayer(net['fc6'], p=0.5)
net['fc7'] = DenseLayer(net['drop6'], num_units=1, nonlinearity=lasagne.nonlinearities.tanh)
# net['fc7'] = DenseLayer(net['pool5'], num_units=nshape_params, nonlinearity=lasagne.nonlinearities.tanh)
output_layer = net['fc7']
output = lasagne.layers.get_output(output_layer)
#3 First half mvoe
learning_rate = 1.0
shape_params_split = T.reshape(shape_params, (nprims, nbatch/2, 2, params_per_prim))
first_half_params = shape_params_split[:,:,0,:]
# Get partial derivatives of half of the.g parameters with respect to the cost and move them
# Have to be careful about splitting to make sure that first half of params are those that render to
# first channel of each image (and not that they render first half of all images in all channels)
# shape_params_split = T.reshape(shape_params, (nprims, nbatch/2, 2, 4))
summed_op = T.sum(output) / nbatch
delta_shape = T.grad(summed_op, shape_params)
delta_shape_split = T.reshape(delta_shape, (nprims, nbatch/2, 2, params_per_prim))
first_half_delta = delta_shape_split[:,:,0,:]
new_first_half = first_half_params - learning_rate * first_half_delta
# Then render this half again to produce new images (width, height, nbatch/2)
res2, scan_updates2 = symbolic_render(nprims, new_first_half, fragCoords, width, height)
res_reshape2 = res2.dimshuffle([2,0,1])
# unchanged images
unchanged_img = res_reshape_split[:,1,:,:]
changed_img = res_reshape_split[:,0,:,:]
eps = 1e-9
diff = T.maximum(eps, (unchanged_img - res_reshape2)**2)
loss1 = T.sum(diff) / (nbatch/2*width*height)
## Loss2 is to force change, avoid plateaus
# diff2 = T.maximum(eps, (changed_img - res_reshape2)**2)
# sumdiff2 = T.sum(diff2) / (nbatch/2*width*height)
# mu = 0
# sigma = 0.05
# a = 1/(sigma*np.sqrt(2*np.pi))
# b = mu
# c = sigma
# loss2 = a*T.exp((-sumdiff2**2)/(2*c**2))/40.0
# loss = loss1 + loss2
param_diff = T.sum(first_half_delta**2)/nbatch
loss2 = -gauss(param_diff, mu=10.0, sigma=100.0)*600
loss = loss1 + loss2
params = lasagne.layers.get_all_params(output_layer, trainable=True)
# network_updates = lasagne.updates.nesterov_momentum(loss, params, learning_rate=1.0, momentum=1.0)
network_updates = lasagne.updates.adam(loss, params)
# network_updates = lasagne.updates.rmsprop(loss, params)
## Merge Updates
for k in network_updates.keys():
assert not(scan_updates.has_key(k))
scan_updates[k] = network_updates[k]
for k in scan_updates2.keys():
# assert not(scan_updates.has_key(k)) #FIXME
scan_updates[k] = scan_updates2[k]
params = lasagne.layers.get_all_params(output_layer)
last_layer_params = T.grad(loss, params[-2])
print("Compiling Loss Function")
netcost = function([fragCoords, shape_params], [loss, loss1, loss2, param_diff, summed_op, delta_shape, res2, last_layer_params, unchanged_img, changed_img, res_reshape2], updates=scan_updates, mode=curr_mode)
return netcost, output_layer
def second_order(nprims = 200, nbatch = 50):
"""Creates a network which takes as input a image and returns a cost.
Network extracts features of image to create shape params which are rendered.
The similarity between the rendered image and the actual image is the cost
"""
width = 224
height = 224
params_per_prim = 3
nshape_params = nprims * params_per_prim
img = T.tensor4("input image")
net = {}
net['input'] = InputLayer((nbatch, 1, 224, 224), input_var = img)
net['conv1'] = ConvLayer(net['input'], num_filters=96, filter_size=7, stride=2)
net['norm1'] = NormLayer(net['conv1'], alpha=0.0001) # caffe has alpha = alpha * pool_size
net['pool1'] = PoolLayer(net['norm1'], pool_size=3, stride=3, ignore_border=False)
net['conv2'] = ConvLayer(net['pool1'], num_filters=256, filter_size=5)
net['pool2'] = PoolLayer(net['conv2'], pool_size=2, stride=2, ignore_border=False)
net['conv3'] = ConvLayer(net['pool2'], num_filters=512, filter_size=3, pad=1)
net['conv4'] = ConvLayer(net['conv3'], num_filters=512, filter_size=3, pad=1)
net['conv5'] = ConvLayer(net['conv4'], num_filters=512, filter_size=3, pad=1)
net['pool5'] = PoolLayer(net['conv5'], pool_size=3, stride=3, ignore_border=False)
net['fc6'] = DenseLayer(net['pool5'], num_units=4096)
net['drop6'] = DropoutLayer(net['fc6'], p=0.5)
net['fc7'] = DenseLayer(net['drop6'], num_units=nshape_params)
# net['fc7'] = DenseLayer(net['pool5'], num_units=nshape_params, nonlinearity=lasagne.nonlinearities.tanh)
output_layer = net['fc7']
output = lasagne.layers.get_output(output_layer)
scaled_output = output - 1
## Render these parameters
shape_params = T.reshape(scaled_output, (nprims, nbatch, params_per_prim))
fragCoords = T.tensor3('fragCoords')
print "Symbolic Render"
res, scan_updates = symbolic_render(nprims, shape_params, fragCoords, width, height)
res_reshape = res.dimshuffle([2,'x',0,1])
# Simply using pixel distance
eps = 1e-9
diff = T.maximum(eps, (res_reshape - img)**2)
loss1 = T.sum(diff) / (224*224*nbatch)
mean_shape = T.mean(shape_params, axis=1) # mean across batches
mean_shape = T.reshape(mean_shape, (nprims, 1, params_per_prim))
scale = 1.0
diff2 = T.maximum(eps, (mean_shape - shape_params)**2)
loss2 = T.sum(diff2) / (nprims * params_per_prim * nbatch)
mu = 0
sigma = 4
a = 1/(sigma*np.sqrt(2*np.pi))
b = mu
c = sigma
loss2 = -a*T.exp((-loss2**2)/(2*c**2))
loss = loss2 + loss1
# Create update expressions for training, i.e., how to modify the
# parameters at each training step. Here, we'll use Stochastic Gradient
# Descent (SGD) with Nesterov momentum, but Lasagne offers plenty more.
params = lasagne.layers.get_all_params(output_layer, trainable=True)
network_updates = lasagne.updates.nesterov_momentum(loss, params, learning_rate=0.01, momentum=0.9)
## Merge Updates
for k in network_updates.keys():
assert not(scan_updates.has_key(k))
scan_updates[k] = network_updates[k]
print("Compiling Loss Function")
grad = T.grad(loss, params[0])
netcost = function([fragCoords, img], [loss, grad, res_reshape, shape_params, diff, loss1, loss2], updates=scan_updates, mode=curr_mode)
# netcost = function([fragCoords, img], loss, updates=scan_updates, mode=curr_mode)
## Generate Render Function to make data
# Generate initial rays
exfragcoords = gen_fragcoords(width, height)
print("Compiling Renderer")
render = make_render(nprims, width, height)
return render, netcost, output_layer