diff --git a/src/pytorch_llid/__init__.py b/src/pytorch_llid/__init__.py new file mode 100644 index 0000000..fc79d63 --- /dev/null +++ b/src/pytorch_llid/__init__.py @@ -0,0 +1 @@ +__version__ = '0.2.1' diff --git a/src/pytorch_llid/__main__.py b/src/pytorch_llid/__main__.py new file mode 100644 index 0000000..8403642 --- /dev/null +++ b/src/pytorch_llid/__main__.py @@ -0,0 +1,3 @@ +import pytorch_llid.llid_score + +pytorch_llid.llid_score.main() diff --git a/src/pytorch_llid/llid_score.py b/src/pytorch_llid/llid_score.py new file mode 100644 index 0000000..c9db09c --- /dev/null +++ b/src/pytorch_llid/llid_score.py @@ -0,0 +1,280 @@ +"""Calculates the LLID between an image and batch of images to evalulate GANs + +The LLID metric calculates the loglikelihood of an image under a target distribution, estimated from a batch of images. + +See --help to see further details. + +Code apapted from https://github.com/bioinf-jku/TTUR to use PyTorch instead +of Tensorflow + +Copyright 2018 Institute of Bioinformatics, JKU Linz + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +""" +import os +import pathlib +from argparse import ArgumentDefaultsHelpFormatter, ArgumentParser + +import numpy as np +import torch +import torchvision.transforms as TF +from PIL import Image +from scipy import linalg +from scipy.stats import multivariate_normal +from torch.nn.functional import adaptive_avg_pool2d + +try: + from tqdm import tqdm +except ImportError: + # If tqdm is not available, provide a mock version of it + def tqdm(x): + return x + +from pytorch_fid.inception import InceptionV3 + +parser = ArgumentParser(formatter_class=ArgumentDefaultsHelpFormatter) +parser.add_argument('--batch-size', type=int, default=50, + help='Batch size to use') +parser.add_argument('--num-workers', type=int, + help=('Number of processes to use for data loading. ' + 'Defaults to `min(8, num_cpus)`')) +parser.add_argument('--device', type=str, default=None, + help='Device to use. Like cuda, cuda:0 or cpu') +parser.add_argument('--dims', type=int, default=2048, + choices=list(InceptionV3.BLOCK_INDEX_BY_DIM), + help=('Dimensionality of Inception features to use. ' + 'By default, uses pool3 features')) +parser.add_argument('path', type=str, nargs=2, + help=('Paths to the generated images or ' + 'to .npz statistic files')) + +IMAGE_EXTENSIONS = {'bmp', 'jpg', 'jpeg', 'pgm', 'png', 'ppm', + 'tif', 'tiff', 'webp'} + + +class ImagePathDataset(torch.utils.data.Dataset): + def __init__(self, files, transforms=None): + self.files = files + self.transforms = transforms + + def __len__(self): + return len(self.files) + + def __getitem__(self, i): + path = self.files[i] + img = Image.open(path).convert('RGB') + if self.transforms is not None: + img = self.transforms(img) + return img + + +def get_activations(files, model, batch_size=50, dims=2048, device='cpu', + num_workers=1): + """Calculates the activations of the pool_3 layer for all images. + + Params: + -- files : List of image files paths + -- model : Instance of inception model + -- batch_size : Batch size of images for the model to process at once. + Make sure that the number of samples is a multiple of + the batch size, otherwise some samples are ignored. This + behavior is retained to match the original FID score + implementation. + -- dims : Dimensionality of features returned by Inception + -- device : Device to run calculations + -- num_workers : Number of parallel dataloader workers + + Returns: + -- A numpy array of dimension (num images, dims) that contains the + activations of the given tensor when feeding inception with the + query tensor. + """ + model.eval() + + if batch_size > len(files): + print(('Warning: batch size is bigger than the data size. ' + 'Setting batch size to data size')) + batch_size = len(files) + + dataset = ImagePathDataset(files, transforms=TF.ToTensor()) + dataloader = torch.utils.data.DataLoader(dataset, + batch_size=batch_size, + shuffle=False, + drop_last=False, + num_workers=num_workers) + + pred_arr = np.empty((len(files), dims)) + + start_idx = 0 + + for batch in tqdm(dataloader): + batch = batch.to(device) + + with torch.no_grad(): + pred = model(batch)[0] + + # If model output is not scalar, apply global spatial average pooling. + # This happens if you choose a dimensionality not equal 2048. + if pred.size(2) != 1 or pred.size(3) != 1: + pred = adaptive_avg_pool2d(pred, output_size=(1, 1)) + + pred = pred.squeeze(3).squeeze(2).cpu().numpy() + + pred_arr[start_idx:start_idx + pred.shape[0]] = pred + + start_idx = start_idx + pred.shape[0] + + return pred_arr + + +def calculate_frechet_distance(mu1, sigma1, mu2, sigma2, eps=1e-6): + """Numpy implementation of the Frechet Distance. + The Frechet distance between two multivariate Gaussians X_1 ~ N(mu_1, C_1) + and X_2 ~ N(mu_2, C_2) is + d^2 = ||mu_1 - mu_2||^2 + Tr(C_1 + C_2 - 2*sqrt(C_1*C_2)). + + Stable version by Dougal J. Sutherland. + + Params: + -- mu1 : Numpy array containing the activations of a layer of the + inception net (like returned by the function 'get_predictions') + for generated samples. + -- mu2 : The sample mean over activations, precalculated on an + representative data set. + -- sigma1: The covariance matrix over activations for generated samples. + -- sigma2: The covariance matrix over activations, precalculated on an + representative data set. + + Returns: + -- : The Frechet Distance. + """ + + mu1 = np.atleast_1d(mu1) + mu2 = np.atleast_1d(mu2) + + sigma1 = np.atleast_2d(sigma1) + sigma2 = np.atleast_2d(sigma2) + + assert mu1.shape == mu2.shape, \ + 'Training and test mean vectors have different lengths' + assert sigma1.shape == sigma2.shape, \ + 'Training and test covariances have different dimensions' + + diff = mu1 - mu2 + + # Product might be almost singular + covmean, _ = linalg.sqrtm(sigma1.dot(sigma2), disp=False) + if not np.isfinite(covmean).all(): + msg = ('fid calculation produces singular product; ' + 'adding %s to diagonal of cov estimates') % eps + print(msg) + offset = np.eye(sigma1.shape[0]) * eps + covmean = linalg.sqrtm((sigma1 + offset).dot(sigma2 + offset)) + + # Numerical error might give slight imaginary component + if np.iscomplexobj(covmean): + if not np.allclose(np.diagonal(covmean).imag, 0, atol=1e-3): + m = np.max(np.abs(covmean.imag)) + raise ValueError('Imaginary component {}'.format(m)) + covmean = covmean.real + + tr_covmean = np.trace(covmean) + + return (diff.dot(diff) + np.trace(sigma1) + + np.trace(sigma2) - 2 * tr_covmean) + + +def calculate_activation_statistics(files, model, batch_size=50, dims=2048, + device='cpu', num_workers=1): + """Calculation of the statistics used by the FID. + Params: + -- files : List of image files paths + -- model : Instance of inception model + -- batch_size : The images numpy array is split into batches with + batch size batch_size. A reasonable batch size + depends on the hardware. + -- dims : Dimensionality of features returned by Inception + -- device : Device to run calculations + -- num_workers : Number of parallel dataloader workers + + Returns: + -- mu : The mean over samples of the activations of the pool_3 layer of + the inception model. + -- sigma : The covariance matrix of the activations of the pool_3 layer of + the inception model. + """ + act = get_activations(files, model, batch_size, dims, device, num_workers) + mu = np.mean(act, axis=0) + sigma = np.cov(act, rowvar=False) + return mu, sigma + + +def compute_statistics_of_path(path, model, batch_size, dims, device, + num_workers=1): + if path.endswith('.npz'): + with np.load(path) as f: + m, s = f['mu'][:], f['sigma'][:] + else: + path = pathlib.Path(path) + files = sorted([file for ext in IMAGE_EXTENSIONS + for file in path.glob('*.{}'.format(ext))]) + m, s = calculate_activation_statistics(files, model, batch_size, + dims, device, num_workers) + + return m, s + + +def calculate_llid_given_paths(paths, batch_size, device, dims, num_workers=1): + """Calculates the likelihood of sample under the specified target distribution""" + for p in paths: + if not os.path.exists(p): + raise RuntimeError('Invalid path: %s' % p) + + #Load Inception-V3 pretrained model + block_idx = InceptionV3.BLOCK_INDEX_BY_DIM[dims] + model = InceptionV3([block_idx]).to(device) + #Compute multivariate gaussian of the target distribution + m1, s1 = compute_statistics_of_path(paths[0], model, batch_size, + dims, device, num_workers) + #Calculates the activations of the pool_3 layer for the sample + act = get_activations([paths[1]], model, batch_size, dims, device, num_workers) + #Compute likelihood of sample under the target distribution, given mean and covariance matrix + likelihood = multivariate_normal.logpdf(act, mean=m1, cov=s1) + + return likelihood + + +def main(): + args = parser.parse_args() + + if args.device is None: + device = torch.device('cuda' if (torch.cuda.is_available()) else 'cpu') + else: + device = torch.device(args.device) + + if args.num_workers is None: + num_avail_cpus = len(os.sched_getaffinity(0)) + num_workers = min(num_avail_cpus, 8) + else: + num_workers = args.num_workers + + likelihood = calculate_llid_given_paths(args.path, + args.batch_size, + device, + args.dims, + num_workers) + print('Likelihood: ', likelihood) + + +if __name__ == '__main__': + main()