def forward(ctx, x, z_tiled, gan, rec_iters, rec_rr, w_lpips, optimizer,
schedular):
# we assume z is already tiled based on rec_rr
assert x.size(0) * rec_rr == z_tiled.size(0)
# important !!! avoid modifying the gradient of input in-place
x = x.detach().clone()
batch_size = x.size(0)
x_tiled = torch.repeat_interleave(x, rec_rr, dim=0)
noise_ramp_length = 0.75 * rec_iters
start_time = time.time()
with torch.enable_grad():
for i in range(rec_iters):
optimizer.zero_grad()
noise_ramp_factor = (
1 -
i / noise_ramp_length)**2 if i <= noise_ramp_length else 0
noise = torch.randn_like(z_tiled) * 0.05 * noise_ramp_factor
gen = gan(z_tiled)
loss_tiled = (gen - x_tiled).pow(2).mean(dim=(1, 2, 3))
perceptual_loss = lpips(gen, x_tiled)
# loss_tiled = l1_loss(gan(z_tiled), x_tiled).mean(dim=(1, 2, 3))
# --- IMPORTANT ---
# different from normal network training where a fixed set of parameters are updated,
# in this case, each instance in a batch has its own parameters to update,
# therefore, the total loss should not be averaged over number of instances
loss = loss_tiled.sum() + w_lpips * perceptual_loss.sum()
loss_logging = per_pixel_l2_dist(gen, x_tiled)
loss.backward()
optimizer.step()
if (i + 1) % 50 == 0:
print(f'===> Iter: {i+1} | '
f'PP-L2: {loss_logging.item():.6f} | '
f'Perceptual: {perceptual_loss.mean().item():.6f} | '
f'Time: {time.time()-start_time:.3f}')
start_time = time.time()
schedular.step()
gen = gan(z_tiled)
loss_tiled = (gen - x_tiled).pow(2).mean(
dim=(1, 2, 3)) + w_lpips * lpips(gen, x_tiled)
loss_tiled = loss_tiled.view(-1, rec_rr) # (B, r)
indices = torch.argmin(loss_tiled, dim=1)
offsets = torch.arange(0, batch_size).cuda() * rec_rr
return gen[indices + offsets].detach().clone(), z_tiled[
indices + offsets].detach().clone()
def forward(ctx, x, z_tiled, gan, rec_iters, rec_rr, w_lpips, optimizer, schedular, latent_std):
# we assume z is already tiled based on rec_rr
assert x.size(0) * rec_rr == z_tiled.size(0)
# important !!! avoid modifying the gradient of input in-place
x = x.detach().clone()
batch_size = x.size(0)
x_tiled = torch.repeat_interleave(x, rec_rr, dim=0)
# noise = torch.randn_like(x_tiled) * 0.5
# x_tiled = x_tiled + noise
start_time = time.time()
with torch.enable_grad():
for i in range(rec_iters):
t = i / rec_iters
lr = get_lr(t, 0.1)
optimizer.param_groups[0]['lr'] = lr
noise_strength = latent_std * 0.05 * max(0, 1 - t / 0.75) ** 2
latent_n = latent_noise(z_tiled, noise_strength.item())
img_gen = gan.synthesis(latent_n)
p_loss = lpips(img_gen, x_tiled).sum()
norm_loss = norm(img_gen, x_tiled).mean(dim=(1, 2, 3)).sum()
# --- IMPORTANT ---
# different from normal network training where a fixed set of parameters are updated,
# in this case, each instance in a batch has its own parameters to update,
# therefore, the total loss should not be averaged over number of instances
loss = w_lpips * p_loss + norm_loss
loss_logging = per_pixel_l2_dist(img_gen, x_tiled)
optimizer.zero_grad()
loss.backward()
optimizer.step()
if (i + 1) % 50 == 0:
print(f'===> Iter: {i+1} | '
f'PP-L2: {loss_logging.item():.6f} | '
f'Perceptual: {p_loss.mean().item():.6f} | '
f'Time: {time.time()-start_time:.3f}')
start_time = time.time()
schedular.step()
gen = gan.synthesis(z_tiled)
loss_tiled = (gen - x_tiled).pow(2).mean(dim=(1, 2, 3)) + w_lpips * lpips(gen, x_tiled)
loss_tiled = loss_tiled.view(-1, rec_rr) # (B, r)
indices = torch.argmin(loss_tiled, dim=1)
offsets = torch.arange(0, batch_size).cuda() * rec_rr
return gen[indices + offsets].detach().clone(), z_tiled[indices + offsets].detach().clone()
if os.path.isfile(result_path):
result_dict = torch.load(result_path)
images_adv = result_dict['input'].cuda()
images_def = result_dict['rec'].cuda()
else:
# print(images)
images_adv = attacker.perturb(images)
images_def, z_def = proj_fn(images_adv)
# print(images_adv)
print(images_def)
# torch.save({'input': images_adv,
# 'rec': images_def,
# 'z_rec': z_def}, result_path)
l2_dist = per_pixel_l2_dist(images, images_adv)
if i % 1 == 0:
clean_path = os.path.join(vis_dir, 'batch_{:04d}_clean.png'.format(i))
adv_path = os.path.join(vis_dir, 'batch_{:04d}_adv.png'.format(i))
def_path = os.path.join(vis_dir, 'batch_{:04d}_def.png'.format(i))
save_image(images, clean_path, nrow=10, padding=2)
save_image(images_adv, adv_path, nrow=10, padding=2)
save_image(images_def, def_path, nrow=10, padding=2)
with torch.no_grad():
pred_clean = predict(images).argmax(dim=1)
pred_adv = predict(images_adv).argmax(dim=1)
pred_def = predict(images_def).argmax(dim=1)
total += labels.size(0)