Topographic Variational Autoencoder

Paper: https://arxiv.org/abs/2109.01394

Getting Started

Install requirements with Anaconda:

conda env create -f environment.yml

Activate the conda environment

conda activate tvae

Install the tvae package

Install the tvae package inside of your conda environment. This allows you to run experiments with the tvae command. At the root of the project directory run (using your environment's pip): pip3 install -e .

If you need help finding your environment's pip, try which python, which should point you to a directory such as .../anaconda3/envs/tvae/bin/ where it will be located.

(Optional) Setup Weights & Biases:

This repository uses Weight & Biases for experiment tracking. By deafult this is set to off. However, if you would like to use this (highly recommended!) functionality, all you have to do is set 'wandb_on': True in the experiment config, and set your account's project and entity names in the tvae/utils/logging.py file.

For more information on making a Weight & Biases account see (creating a weights and biases account) and the associated quickstart guide.

Running an experiment

To rerun the experiment from Figure 3, you can run:

• tvae --name 'tvae_2d_mnist'

To rerun the experiments from Figure 4, you can run:

• tvae --name 'tvae_Lpartial_mnist'
• tvae --name 'tvae_Lpartial_dsprites'

To rerun the experiments from Tables 1, you can run:

• tvae --name 'tvae_Lhalf_mnist'
• tvae --name 'tvae_Lshort_mnist'
• tvae --name 'bubbles_mnist'
• tvae --name 'tvae_L0_mnist'
• tvae --name 'nontvae_mnist'

To rerun the experiments from Tables 2, you can run:

• tvae --name 'tvae_Lhalf_dsprites'
• tvae --name 'tvae_Lpartial_dsprites'
• tvae --name 'tvae_Lshort_dsprites'
• tvae --name 'bubbles_dsprites'
• tvae --name 'tvae_L0_dsprites'
• tvae --name 'nontvae_dsprites'

To rerun the generalization experiment described in Section B.4 (resulting in Figures 1 and 6), you can run:

• tvae --name 'tvae_Lpartial_mnist_generalization'

To rerun the experiments from Figures 22 and 23 (training on complex combined transformations), you can run:

• tvae --name 'tvae_Lpartial_perspective_mnist'
• tvae --name 'tvae_Lpartial_rotcolor_mnist'

Basics of the framework

• All models are built using the TVAE module (see tvae/containers/tvae.py) which requires a z-encoder, a u-encoder, a decoder, and a 'grouper'. The grouper module defines the topographic structure of the latent space through a model (equivalent to W in the paper), and a padder which defines the boundary conditions.
• All experiments can be found in tvae/experiments/, and begin with the model specification, followed by the experiment config where important values such as L (group_kernel) and K (n_off_diag) can be set.

Model Architecutre Options

• 'n_caps': int, Number of independnt capsules
• 'cap_dim': int, Size of each capsule
• 'n_transforms': int, Length of the total transformation sequence (denoted S in the paper)
• 'mu_init': int, Initalization value for mu parameter
• 'n_off_diag': int, determines the spatial extent of the grouping within a single timestep (denoted K in the paper), n_off_diag=1 gives K=3, while n_off_diag=0 gives K=1.
• 'group_kernel': tuple of int, defines the size of the kernel used by the grouper, exact definition and relationship to W varies for each experiment.

Training Options

• 'wandb_on': bool, if True, use weights & biases logging
• 'lr': float, learning rate
• 'momentum': float, standard momentum used in SGD
• 'max_epochs': int, total training epochs
• 'eval_epochs': int, epochs between evaluation on the test (for MNIST)
• 'batch_size': int, number of samples per batch
• 'n_is_samples': int, number of importance samples when computing the log-likelihood on MNIST.
• 'max_transform_len': int, (for dSprites) controls the subset of the dataset

Acknowledgements

The Robert Bosch GmbH is acknowledged for financial support.