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# Copyright (c) 2019, NVIDIA CORPORATION. All rights reserved. | |
# | |
# This work is licensed under the Creative Commons Attribution-NonCommercial | |
# 4.0 International License. To view a copy of this license, visit | |
# http://creativecommons.org/licenses/by-nc/4.0/ or send a letter to | |
# Creative Commons, PO Box 1866, Mountain View, CA 94042, USA. | |
"""Frechet Inception Distance (FID).""" | |
import os | |
import numpy as np | |
import scipy | |
import tensorflow as tf | |
import dnnlib.tflib as tflib | |
from metrics import metric_base | |
from training import misc | |
#---------------------------------------------------------------------------- | |
class FID(metric_base.MetricBase): | |
def __init__(self, num_images, minibatch_per_gpu, **kwargs): | |
super().__init__(**kwargs) | |
self.num_images = num_images | |
self.minibatch_per_gpu = minibatch_per_gpu | |
def _evaluate(self, Gs, num_gpus): | |
minibatch_size = num_gpus * self.minibatch_per_gpu | |
inception = misc.load_pkl('https://drive.google.com/uc?id=1MzTY44rLToO5APn8TZmfR7_ENSe5aZUn') # inception_v3_features.pkl | |
activations = np.empty([self.num_images, inception.output_shape[1]], dtype=np.float32) | |
# Calculate statistics for reals. | |
cache_file = self._get_cache_file_for_reals(num_images=self.num_images) | |
os.makedirs(os.path.dirname(cache_file), exist_ok=True) | |
if os.path.isfile(cache_file): | |
mu_real, sigma_real = misc.load_pkl(cache_file) | |
else: | |
for idx, images in enumerate(self._iterate_reals(minibatch_size=minibatch_size)): | |
begin = idx * minibatch_size | |
end = min(begin + minibatch_size, self.num_images) | |
activations[begin:end] = inception.run(images[:end-begin], num_gpus=num_gpus, assume_frozen=True) | |
if end == self.num_images: | |
break | |
mu_real = np.mean(activations, axis=0) | |
sigma_real = np.cov(activations, rowvar=False) | |
misc.save_pkl((mu_real, sigma_real), cache_file) | |
# Construct TensorFlow graph. | |
result_expr = [] | |
for gpu_idx in range(num_gpus): | |
with tf.device('/gpu:%d' % gpu_idx): | |
Gs_clone = Gs.clone() | |
inception_clone = inception.clone() | |
latents = tf.random_normal([self.minibatch_per_gpu] + Gs_clone.input_shape[1:]) | |
images = Gs_clone.get_output_for(latents, None, is_validation=True, randomize_noise=True) | |
images = tflib.convert_images_to_uint8(images) | |
result_expr.append(inception_clone.get_output_for(images)) | |
# Calculate statistics for fakes. | |
for begin in range(0, self.num_images, minibatch_size): | |
end = min(begin + minibatch_size, self.num_images) | |
activations[begin:end] = np.concatenate(tflib.run(result_expr), axis=0)[:end-begin] | |
mu_fake = np.mean(activations, axis=0) | |
sigma_fake = np.cov(activations, rowvar=False) | |
# Calculate FID. | |
m = np.square(mu_fake - mu_real).sum() | |
s, _ = scipy.linalg.sqrtm(np.dot(sigma_fake, sigma_real), disp=False) # pylint: disable=no-member | |
dist = m + np.trace(sigma_fake + sigma_real - 2*s) | |
self._report_result(np.real(dist)) | |
#---------------------------------------------------------------------------- | |