Bayesian Bidrectional GAN

By Julie Jiang and Daniel Dinjian.

Final project for COMP150 Bayesian Deep Learning (Fall 2018), Tufts University.

Instructor: Mike Huges

Code is forked from Bidrectional GAN, with references to BayesGAN.

You can read our final paper.

Dependencies

This code has the following dependencies (version number crucial):

python 3.6
theano 0.9
cuda 8.0
cudnn 5.1
numpy

Permutation-invariant MNIST

Setup

Download the MNIST dataset to a directory called mnist and set your enviroment variable to the path to the mnist directory:

export DATADIR=/path/to/datasets/

This directory should contain the MNIST data files (or symlinks to them) with these names:

t10k-images.idx3-ubyte
t10k-labels.idx1-ubyte
train-images.idx3-ubyte
train-labels.idx1-ubyte

Before running the experiment, setup theano by running:

source theanosetup.sh

The train_mnist.sh script trains a "permutation-invariant" BiGAN (by default) on the MNIST dataset.

BiGAN

The BiGAN discriminator (or "joint discriminator") is enabled by setting a non-zero joint_discrim_weight, and the number of MC samples of the generator is set with num_generator.

OBJECTIVE="--encode_gen_weight 1 --encode_weight 0 --discrim_weight 0 --joint_discrim_weight 1"
./train_mnist.sh $OBJECTIVE --num_generator 1 --exp_dir ./exp

This should produce output like:

0) JD: 0.6932  E: 0.6932  G0: 0.6932
NNC_e: 91.53%  NNC_e-: 96.84%  CLS_e-: 91.44%  NND_g0_/100: 13.54  NND_g0_/10: 13.48  NND_g0_: 13.44  EGg0: 3.00  EGg0_b: 3.00
...
100) JD: 0.3539  E: 1.8842  G0: 1.7892
NNC_e: 94.20%  NNC_e-: 95.41%  CLS_e-: 89.90%  NND_g0_/100: 5.40  NND_g0_/10: 4.80  NND_g0_: 4.41  EGg0: 6.39  EGg0_b: 8.11
...
200) JD: 0.2076  E: 2.5187  G0: 2.7372
NNC_e: 95.50%  NNC_e-: 96.44%  CLS_e-: 90.96%  NND_g0_/100: 5.49  NND_g0_/10: 4.79  NND_g0_: 4.29  EGg0: 5.46  EGg0_b: 9.33
...

The first line of each output shows the loss (objective value) of each module -- in this case the joint discriminator (JD), encoder (E), and generator (G). Here the encoder and generator losses are always equal, but this is not always the case (as in the latent regressor below).

The second line contains various measures of accuracy.

• NND* measures generation quality (lower is better).
• NNC* and CLS* measure "feature" quality by either a 1-nearest-neighbor (NNC) or logistic regression (CLS) classifier (higher is better).
  • *_e and *_e- denote the feature space, with _e being E(x) itself, and _e- being the layer of encoder features immediately before the output. (The latter normally works better.)
• EG* measures reconstruction error (lower is better).
  • EGr is L2 error || x - G(E(x)) ||, averaged across real data samples x ~ p(x)
  • EGg is also L2 error, but averaged across generated samples x = G(z), z ~ p(z): || G(z) - G(E(G(z))) ||
  • The corresponding *_b measures are "baselines", where the reconstruction error is computed against a random input, i.e. || x' - G(E(x)) || where x and x' are each random samples. The ratio EGr / EGr_b gives a more meaningful notion of reconstruction accuracy than EGr alone; e.g., if EGr ~= EGr_b as in epoch 0 above, no meaningful reconstruction is happening.

After training, the image samples are saved in a subdirectory in the directory specified in --exp_dir (in this case, ./exp/bigan_mnist_* where * is the time at which the directory is created).

CIFAR

Please download the CIFAR10 dataset and use the make sure that $DATADIR/cifar/cifar-10-batches-py is a valid directory. When training indicate that the dataset is cifar.

train_cifar.sh contains the script to train the cifar dataset.

Contact

Please contact [email protected] or [email protected] for any questions.