def forward(self, inputs):
if len(inputs) != 2:
raise ValueError('expected two inputs: predictions and labels')
pred = inputs[0]
label = inputs[1]
ones = p.Constant(hint_layer=pred, value=1.0)
term1 = lbann.Multiply(
[label, lbann.Log(lbann.Subtract([ones, pred]))])
term2 = lbann.Log(pred)
full = lbann.WeightedSum([term1, term2], scaling_factors='-1.0 -1.0')
return lbann.Reduction(full)
def forward(self, inputs):
if len(inputs) != 2:
raise ValueError('expected two inputs: predictions and labels')
pred = inputs[0]
label = inputs[1] # Assumed to be Boolean
masked_pred = lbann.Multiply([pred, label])
pred_sum = lbann.Reduction(masked_pred)
return lbann.Negative(lbann.Log(pred_sum))
def forward(self, inputs):
raise NotImplementedError # Requires log-gamma function
if len(inputs) != 2:
raise ValueError('expected two inputs: predictions and labels')
pred = inputs[0]
label = inputs[1]
ones = lbann.Constant(hint_layer=pred, value=1.0)
term1 = pred
term2 = lbann.Multiply([label, lbann.Log(pred)])
term3 = lbann.LogGamma(lbann.Add([label, ones]))
full = lbann.WeightedSum([term1, term2, term3],
scaling_factors='1.0 -1.0 1.0')
return lbann.Reduction(full)
def forward(
self,
motif_indices,
motif_size,
walk_indices,
walk_length,
):
# Apply generator
fake_motif_indices, gen_prob, gen_log_prob = self.generator(
walk_length,
walk_indices,
motif_size,
)
# Get discriminator embeddings in log-space
all_motif_indices = lbann.Concatenation(motif_indices,
fake_motif_indices)
all_motif_log_embeddings = self.discriminator.get_log_embeddings(
all_motif_indices)
all_motif_log_embeddings = lbann.Slice(
all_motif_log_embeddings,
slice_points=str_list([0, motif_size, 2 * motif_size]),
)
real_motif_log_embeddings = lbann.Identity(all_motif_log_embeddings)
fake_motif_log_embeddings = lbann.Identity(all_motif_log_embeddings)
# Apply discriminator
real_disc_prob, real_disc_log_not_prob \
= self.discriminator(motif_size, real_motif_log_embeddings)
fake_disc_prob, fake_disc_log_not_prob \
= self.discriminator(motif_size, fake_motif_log_embeddings)
# Loss function
# L_disc = - log(D(real)) - log(1-D(fake))
# L_gen = - log(G) * stop_gradient(log(1-D(fake)))
real_disc_log_prob \
= lbann.Log(lbann.Clamp(real_disc_prob, min=1e-37, max=1))
disc_loss = lbann.WeightedSum(
real_disc_log_prob,
fake_disc_log_not_prob,
scaling_factors=str_list([-1, -1]),
)
gen_loss = lbann.Multiply(
gen_log_prob,
lbann.StopGradient(fake_disc_log_not_prob),
)
loss = lbann.Add(disc_loss, gen_loss)
return loss, real_disc_prob, fake_disc_prob, gen_prob
def construct_model(num_epochs,mcr,spectral_loss,save_batch_interval):
"""Construct LBANN model.
"""
import lbann
# Layer graph
input = lbann.Input(target_mode='N/A',name='inp_img')
### Create expected labels for real and fake data (with label flipping = 0.01)
prob_flip=0.01
label_flip_rand = lbann.Uniform(min=0,max=1, neuron_dims='1')
label_flip_prob = lbann.Constant(value=prob_flip, num_neurons='1')
ones = lbann.GreaterEqual(label_flip_rand,label_flip_prob, name='is_real')
zeros = lbann.LogicalNot(ones,name='is_fake')
gen_ones=lbann.Constant(value=1.0,num_neurons='1')## All ones: no flip. Input for training Generator.
#==============================================
### Implement GAN
##Create the noise vector
z = lbann.Reshape(lbann.Gaussian(mean=0.0,stdev=1.0, neuron_dims="64", name='noise_vec'),dims='1 64')
## Creating the GAN object and implementing forward pass for both networks ###
d1_real, d1_fake, d_adv, gen_img, img = ExaGAN.CosmoGAN(mcr)(input,z,mcr)
#==============================================
### Compute quantities for adding to Loss and Metrics
d1_real_bce = lbann.SigmoidBinaryCrossEntropy([d1_real,ones],name='d1_real_bce')
d1_fake_bce = lbann.SigmoidBinaryCrossEntropy([d1_fake,zeros],name='d1_fake_bce')
d_adv_bce = lbann.SigmoidBinaryCrossEntropy([d_adv,gen_ones],name='d_adv_bce')
#img_loss = lbann.MeanSquaredError([gen_img,img])
#l1_loss = lbann.L1Norm(lbann.WeightedSum([gen_img,img], scaling_factors="1 -1"))
#==============================================
### Set up source and destination layers
layers = list(lbann.traverse_layer_graph(input))
weights = set()
src_layers,dst_layers = [],[]
for l in layers:
if(l.weights and "disc1" in l.name and "instance1" in l.name):
src_layers.append(l.name)
#freeze weights in disc2, analogous to discrim.trainable=False in Keras
if(l.weights and "disc2" in l.name):
dst_layers.append(l.name)
for idx in range(len(l.weights)):
l.weights[idx].optimizer = lbann.NoOptimizer()
weights.update(l.weights)
#l2_reg = lbann.L2WeightRegularization(weights=weights, scale=1e-4)
#==============================================
### Define Loss and Metrics
#Define loss (Objective function)
loss_list=[d1_real_bce,d1_fake_bce,d_adv_bce] ## Usual GAN loss function
# loss_list=[d1_real_bce,d1_fake_bce] ## skipping adversarial loss for G for testing spectral loss
if spectral_loss:
dft_gen_img = lbann.DFTAbs(gen_img)
dft_img = lbann.StopGradient(lbann.DFTAbs(img))
spec_loss = lbann.Log(lbann.MeanSquaredError(dft_gen_img, dft_img))
loss_list.append(lbann.LayerTerm(spec_loss, scale=8.0))
loss = lbann.ObjectiveFunction(loss_list)
#Define metrics
metrics = [lbann.Metric(d1_real_bce,name='d_real'),lbann.Metric(d1_fake_bce, name='d_fake'), lbann.Metric(d_adv_bce,name='gen_adv')]
if spectral_loss: metrics.append(lbann.Metric(spec_loss,name='spec_loss'))
#==============================================
### Define callbacks list
callbacks_list=[]
dump_outputs=True
save_model=False
print_model=False
callbacks_list.append(lbann.CallbackPrint())
callbacks_list.append(lbann.CallbackTimer())
callbacks_list.append(lbann.CallbackReplaceWeights(source_layers=list2str(src_layers), destination_layers=list2str(dst_layers),batch_interval=1))
if dump_outputs:
#callbacks_list.append(lbann.CallbackDumpOutputs(layers='inp_img gen_img_instance1_activation', execution_modes='train validation', directory='dump_outs',batch_interval=save_batch_interval,format='npy'))
callbacks_list.append(lbann.CallbackDumpOutputs(layers='gen_img_instance1_activation', execution_modes='train validation', directory='dump_outs',batch_interval=save_batch_interval,format='npy'))
if save_model : callbacks_list.append(lbann.CallbackSaveModel(dir='models'))
if print_model: callbacks_list.append(lbann.CallbackPrintModelDescription())
### Construct model
return lbann.Model(num_epochs,
weights=weights,
layers=layers,
metrics=metrics,
objective_function=loss,
callbacks=callbacks_list)
def compute_loss(self, x, y):
# y[:, :-1]
y = lbann.Slice(
y,
axis=0,
slice_points=str_list([0, self.input_feature_dims - 1]),
)
y = lbann.Identity(y)
# x[:, 1:]
x = lbann.Slice(
x,
slice_points=str_list([1, self.input_feature_dims]),
)
x = lbann.Identity(x)
# Convert indices in x to one-hot representation
# Note: Ignored indices result in zero vectors
ignore_mask = lbann.Equal(
x,
self.constant(self.label_to_ignore, hint_layer=x),
)
keep_mask = lbann.LogicalNot(ignore_mask)
length = lbann.Reduction(keep_mask, mode='sum')
length = lbann.Max(length, self.constant(1, [1]))
x = lbann.Add(
lbann.Multiply(keep_mask, x),
lbann.Multiply(ignore_mask, self.constant(-1, hint_layer=x)),
)
x = lbann.Slice(x,
slice_points=str_list(range(self.input_feature_dims)))
x = [lbann.Identity(x) for _ in range(self.input_feature_dims - 1)]
x = [lbann.OneHot(xi, size=self.dictionary_size) for xi in x]
x = [
lbann.Reshape(xi, dims=str_list([1, self.dictionary_size]))
for xi in x
]
x = lbann.Concatenation(x, axis=0)
# recon_loss = F.cross_entropy(
# y[:, :-1].contiguous().view(-1, y.size(-1)),
# x[:, 1:].contiguous().view(-1),
# ignore_index=self.pad
# )
# Note: Ideally we'd shift y by y.max(-1) for numerical stability
shifts = lbann.MatMul(
lbann.Max(y, self.constant(0, hint_layer=y)),
self.constant(
1 / math.sqrt(self.dictionary_size),
[self.dictionary_size, self.dictionary_size],
),
)
y = lbann.Subtract(y, shifts)
z = lbann.MatMul(
lbann.Exp(y),
self.constant(1, [self.dictionary_size, 1]),
)
z = lbann.Log(z)
z = lbann.MatMul(
lbann.Reshape(keep_mask, dims=str_list([1, -1])),
z,
)
recon_loss = lbann.MatMul(
lbann.Reshape(y, dims=str_list([1, -1])),
lbann.Reshape(x, dims=str_list([1, -1])),
transpose_b=True,
)
recon_loss = lbann.Subtract(z, recon_loss)
recon_loss = lbann.Reshape(recon_loss, dims=str_list([1]))
recon_loss = lbann.Divide(recon_loss, length)
return recon_loss
def compute_loss(self, x, y):
# y[:, :-1]
y = lbann.Slice(
y,
axis=0,
slice_points=str_list([0, self.input_feature_dims-1]),
)
y = lbann.Identity(y)
# x[:, 1:]
x = lbann.Slice(
x,
slice_points=str_list([1, self.input_feature_dims]),
)
x = lbann.Identity(x)
# Figure out entries in x to ignore
ignore_mask = lbann.Equal(
x,
self.constant(self.label_to_ignore, hint_layer=x),
)
keep_mask = lbann.LogicalNot(ignore_mask)
length = lbann.Reduction(keep_mask, mode='sum')
length = lbann.Max(length, self.constant(1, [1]))
# Convert entries in x to indices in y
# Note: Ignored entries correspond to an index of -1.
offsets = [
row*self.dictionary_size
for row in range(self.input_feature_dims-1)
]
offsets = lbann.Weights(
initializer=lbann.ValueInitializer(values=str_list(offsets)),
optimizer=lbann.NoOptimizer(),
)
offsets = lbann.WeightsLayer(
dims=str_list([self.input_feature_dims-1]),
weights=offsets,
)
y_inds = lbann.Add(x, offsets)
y_inds = lbann.Add(
lbann.Multiply(keep_mask, y_inds),
lbann.Multiply(
ignore_mask,
self.constant(-1, hint_layer=y_inds),
),
)
# recon_loss = F.cross_entropy(
# y[:, :-1].contiguous().view(-1, y.size(-1)),
# x[:, 1:].contiguous().view(-1),
# ignore_index=self.pad
# )
# Shift y for numerical stability
# Note: We'd prefer to shift by y.max(-1)
shifts = lbann.MatMul(
lbann.Max(y, self.constant(0, hint_layer=y)),
self.constant(
1 / math.sqrt(self.dictionary_size),
[self.dictionary_size, self.dictionary_size],
),
)
y = lbann.Subtract(y, shifts)
# Compute log of softmax denominator and sum
z = lbann.MatMul(
lbann.Exp(y),
self.constant(1, [self.dictionary_size, 1]),
)
z = lbann.Log(z)
z = lbann.MatMul(
lbann.Reshape(keep_mask, dims=str_list([1, -1])),
z,
)
z = lbann.Reshape(z, dims=str_list([1]))
# Compute cross entropy
recon_loss = lbann.Gather(
lbann.Reshape(y, dims=str_list([-1])),
y_inds,
)
recon_loss = lbann.Reduction(recon_loss, mode='sum')
recon_loss = lbann.Subtract(z, recon_loss)
recon_loss = lbann.Divide(recon_loss, length)
return recon_loss