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| import argparse | |
| import torch | |
| from torch.nn import functional as F | |
| import numpy as np | |
| from tqdm import tqdm | |
| import lpips | |
| from model import Generator | |
| def normalize(x): | |
| return x / torch.sqrt(x.pow(2).sum(-1, keepdim=True)) | |
| def slerp(a, b, t): | |
| a = normalize(a) | |
| b = normalize(b) | |
| d = (a * b).sum(-1, keepdim=True) | |
| p = t * torch.acos(d) | |
| c = normalize(b - d * a) | |
| d = a * torch.cos(p) + c * torch.sin(p) | |
| return normalize(d) | |
| def lerp(a, b, t): | |
| return a + (b - a) * t | |
| if __name__ == '__main__': | |
| device = 'cuda' | |
| parser = argparse.ArgumentParser() | |
| parser.add_argument('--space', choices=['z', 'w']) | |
| parser.add_argument('--batch', type=int, default=64) | |
| parser.add_argument('--n_sample', type=int, default=5000) | |
| parser.add_argument('--size', type=int, default=256) | |
| parser.add_argument('--eps', type=float, default=1e-4) | |
| parser.add_argument('--crop', action='store_true') | |
| parser.add_argument('ckpt', metavar='CHECKPOINT') | |
| args = parser.parse_args() | |
| latent_dim = 512 | |
| ckpt = torch.load(args.ckpt) | |
| g = Generator(args.size, latent_dim, 8).to(device) | |
| g.load_state_dict(ckpt['g_ema']) | |
| g.eval() | |
| percept = lpips.PerceptualLoss( | |
| model='net-lin', net='vgg', use_gpu=device.startswith('cuda') | |
| ) | |
| distances = [] | |
| n_batch = args.n_sample // args.batch | |
| resid = args.n_sample - (n_batch * args.batch) | |
| batch_sizes = [args.batch] * n_batch + [resid] | |
| with torch.no_grad(): | |
| for batch in tqdm(batch_sizes): | |
| noise = g.make_noise() | |
| inputs = torch.randn([batch * 2, latent_dim], device=device) | |
| lerp_t = torch.rand(batch, device=device) | |
| if args.space == 'w': | |
| latent = g.get_latent(inputs) | |
| latent_t0, latent_t1 = latent[::2], latent[1::2] | |
| latent_e0 = lerp(latent_t0, latent_t1, lerp_t[:, None]) | |
| latent_e1 = lerp(latent_t0, latent_t1, lerp_t[:, None] + args.eps) | |
| latent_e = torch.stack([latent_e0, latent_e1], 1).view(*latent.shape) | |
| image, _ = g([latent_e], input_is_latent=True, noise=noise) | |
| if args.crop: | |
| c = image.shape[2] // 8 | |
| image = image[:, :, c * 3 : c * 7, c * 2 : c * 6] | |
| factor = image.shape[2] // 256 | |
| if factor > 1: | |
| image = F.interpolate( | |
| image, size=(256, 256), mode='bilinear', align_corners=False | |
| ) | |
| dist = percept(image[::2], image[1::2]).view(image.shape[0] // 2) / ( | |
| args.eps ** 2 | |
| ) | |
| distances.append(dist.to('cpu').numpy()) | |
| distances = np.concatenate(distances, 0) | |
| lo = np.percentile(distances, 1, interpolation='lower') | |
| hi = np.percentile(distances, 99, interpolation='higher') | |
| filtered_dist = np.extract( | |
| np.logical_and(lo <= distances, distances <= hi), distances | |
| ) | |
| print('ppl:', filtered_dist.mean()) | |