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@Pinnh @eriklindernoren
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import argparse
import os
import numpy as np
import math
import sys
import torchvision.transforms as transforms
from torchvision.utils import save_image
from torch.utils.data import DataLoader
from torchvision import datasets
from torch.autograd import Variable
import torch.nn as nn
import torch.nn.functional as F
import torch.autograd as autograd
import torch
os.makedirs("images", exist_ok=True)
parser = argparse.ArgumentParser()
parser.add_argument("--n_epochs", type=int, default=200, help="number of epochs of training")
parser.add_argument("--batch_size", type=int, default=64, help="size of the batches")
parser.add_argument("--lr", type=float, default=0.0002, help="adam: learning rate")
parser.add_argument("--b1", type=float, default=0.5, help="adam: decay of first order momentum of gradient")
parser.add_argument("--b2", type=float, default=0.999, help="adam: decay of first order momentum of gradient")
parser.add_argument("--n_cpu", type=int, default=8, help="number of cpu threads to use during batch generation")
parser.add_argument("--latent_dim", type=int, default=100, help="dimensionality of the latent space")
parser.add_argument("--img_size", type=int, default=28, help="size of each image dimension")
parser.add_argument("--channels", type=int, default=1, help="number of image channels")
parser.add_argument("--n_critic", type=int, default=5, help="number of training steps for discriminator per iter")
parser.add_argument("--clip_value", type=float, default=0.01, help="lower and upper clip value for disc. weights")
parser.add_argument("--sample_interval", type=int, default=400, help="interval betwen image samples")
opt = parser.parse_args()
print(opt)
img_shape = (opt.channels, opt.img_size, opt.img_size)
cuda = True if torch.cuda.is_available() else False
class Generator(nn.Module):
def __init__(self):
super(Generator, self).__init__()
def block(in_feat, out_feat, normalize=True):
layers = [nn.Linear(in_feat, out_feat)]
if normalize:
layers.append(nn.BatchNorm1d(out_feat, 0.8))
layers.append(nn.LeakyReLU(0.2, inplace=True))
return layers
self.model = nn.Sequential(
*block(opt.latent_dim, 128, normalize=False),
*block(128, 256),
*block(256, 512),
*block(512, 1024),
nn.Linear(1024, int(np.prod(img_shape))),
nn.Tanh()
)
def forward(self, z):
img = self.model(z)
img = img.view(img.shape[0], *img_shape)
return img
class Discriminator(nn.Module):
def __init__(self):
super(Discriminator, self).__init__()
self.model = nn.Sequential(
nn.Linear(int(np.prod(img_shape)), 512),
nn.LeakyReLU(0.2, inplace=True),
nn.Linear(512, 256),
nn.LeakyReLU(0.2, inplace=True),
nn.Linear(256, 1),
)
def forward(self, img):
img_flat = img.view(img.shape[0], -1)
validity = self.model(img_flat)
return validity
k = 2
p = 6
# Initialize generator and discriminator
generator = Generator()
discriminator = Discriminator()
if cuda:
generator.cuda()
discriminator.cuda()
# Configure data loader
os.makedirs("../../data/mnist", exist_ok=True)
dataloader = torch.utils.data.DataLoader(
datasets.MNIST(
"../../data/mnist",
train=True,
download=True,
transform=transforms.Compose(
[transforms.Resize(opt.img_size), transforms.ToTensor(), transforms.Normalize([0.5], [0.5])]
),
),
batch_size=opt.batch_size,
shuffle=True,
)
# Optimizers
optimizer_G = torch.optim.Adam(generator.parameters(), lr=opt.lr, betas=(opt.b1, opt.b2))
optimizer_D = torch.optim.Adam(discriminator.parameters(), lr=opt.lr, betas=(opt.b1, opt.b2))
Tensor = torch.cuda.FloatTensor if cuda else torch.FloatTensor
# ----------
# Training
# ----------
batches_done = 0
for epoch in range(opt.n_epochs):
for i, (imgs, _) in enumerate(dataloader):
# Configure input
real_imgs = Variable(imgs.type(Tensor), requires_grad=True)
# ---------------------
# Train Discriminator
# ---------------------
optimizer_D.zero_grad()
# Sample noise as generator input
z = Variable(Tensor(np.random.normal(0, 1, (imgs.shape[0], opt.latent_dim))))
# Generate a batch of images
fake_imgs = generator(z)
# Real images
real_validity = discriminator(real_imgs)
# Fake images
fake_validity = discriminator(fake_imgs)
# Compute W-div gradient penalty
real_grad_out = Variable(Tensor(real_imgs.size(0), 1).fill_(1.0), requires_grad=False)
real_grad = autograd.grad(
real_validity, real_imgs, real_grad_out, create_graph=True, retain_graph=True, only_inputs=True
)[0]
real_grad_norm = real_grad.view(real_grad.size(0), -1).pow(2).sum(1) ** (p / 2)
fake_grad_out = Variable(Tensor(fake_imgs.size(0), 1).fill_(1.0), requires_grad=False)
fake_grad = autograd.grad(
fake_validity, fake_imgs, fake_grad_out, create_graph=True, retain_graph=True, only_inputs=True
)[0]
fake_grad_norm = fake_grad.view(fake_grad.size(0), -1).pow(2).sum(1) ** (p / 2)
div_gp = torch.mean(real_grad_norm + fake_grad_norm) * k / 2
# Adversarial loss
d_loss = -torch.mean(real_validity) + torch.mean(fake_validity) + div_gp
d_loss.backward()
optimizer_D.step()
optimizer_G.zero_grad()
# Train the generator every n_critic steps
if i % opt.n_critic == 0:
# -----------------
# Train Generator
# -----------------
# Generate a batch of images
fake_imgs = generator(z)
# Loss measures generator's ability to fool the discriminator
# Train on fake images
fake_validity = discriminator(fake_imgs)
g_loss = -torch.mean(fake_validity)
g_loss.backward()
optimizer_G.step()
print(
"[Epoch %d/%d] [Batch %d/%d] [D loss: %f] [G loss: %f]"
% (epoch, opt.n_epochs, i, len(dataloader), d_loss.item(), g_loss.item())
)
if batches_done % opt.sample_interval == 0:
save_image(fake_imgs.data[:25], "images/%d.png" % batches_done, nrow=5, normalize=True)
batches_done += opt.n_critic
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