Barba, Luis
Using Machine Learning for move sequence visualization and generation in climbing
Rimbot, Thomas, Jaggi, Martin, Barba, Luis
Using Machine Learning for move sequence visualization and generation in climbing Thomas Rimbot, Martin Jaggi, Luis Barba - EPFL Abstract --In this work, we investigate the application of Machine Learning techniques to sport climbing. Expanding upon previous projects, we develop a visualization tool for move sequence evaluation on a given boulder . Then, we look into move sequence prediction from simple holds sequence information using three different Transformer models. While the results are not conclusive, they are a first step in this kind of approach and lay the ground for future work. I NTRODUCTION Applying Machine Learning techniques to competitive sport has been an increasing trend in the past few years. We can for example cite the case of car racing or hockey. In this project, we focus on bouldering, a form of rock climbing where athletes are tasked with overcoming a small natural or artificial feature (about 4m high), requiring both physical strengths and problem-solving skills.
Bridging the Gap: Addressing Discrepancies in Diffusion Model Training for Classifier-Free Guidance
Patel, Niket, Salamanca, Luis, Barba, Luis
Diffusion models have emerged as a pivotal advancement in generative models, setting new standards to the quality of the generated instances. In the current paper we aim to underscore a discrepancy between conventional training methods and the desired conditional sampling behavior of these models. While the prevalent classifier-free guidance technique works well, it's not without flaws. At higher values for the guidance scale parameter $w$, we often get out of distribution samples and mode collapse, whereas at lower values for $w$ we may not get the desired specificity. To address these challenges, we introduce an updated loss function that better aligns training objectives with sampling behaviors. Experimental validation with FID scores on CIFAR-10 elucidates our method's ability to produce higher quality samples with fewer sampling timesteps, and be more robust to the choice of guidance scale $w$. We also experiment with fine-tuning Stable Diffusion on the proposed loss, to provide early evidence that large diffusion models may also benefit from this refined loss function.
Implicit Gradient Alignment in Distributed and Federated Learning
Dandi, Yatin, Barba, Luis, Jaggi, Martin
A major obstacle to achieving global convergence in distributed and federated learning is the misalignment of gradients across clients, or mini-batches due to heterogeneity and stochasticity of the distributed data. One way to alleviate this problem is to encourage the alignment of gradients across different clients throughout training. Our analysis reveals that this goal can be accomplished by utilizing the right optimization method that replicates the implicit regularization effect of SGD, leading to gradient alignment as well as improvements in test accuracies. Since the existence of this regularization in SGD completely relies on the sequential use of different mini-batches during training, it is inherently absent when training with large mini-batches. To obtain the generalization benefits of this regularization while increasing parallelism, we propose a novel GradAlign algorithm that induces the same implicit regularization while allowing the use of arbitrarily large batches in each update. We experimentally validate the benefit of our algorithm in different distributed and federated learning settings.
Dynamic Model Pruning with Feedback
Lin, Tao, Stich, Sebastian U., Barba, Luis, Dmitriev, Daniil, Jaggi, Martin
Deep neural networks often have millions of parameters. This can hinder their deployment to low-end devices, not only due to high memory requirements but also because of increased latency at inference. We propose a novel model compression method that generates a sparse trained model without additional overhead: by allowing (i) dynamic allocation of the sparsity pattern and (ii) incorporating feedback signal to reactivate prematurely pruned weights we obtain a performant sparse model in one single training pass (retraining is not needed, but can further improve the performance). We evaluate our method on CIFAR-10 and ImageNet, and show that the obtained sparse models can reach the state-of-the-art performance of dense models. Moreover, their performance surpasses that of models generated by all previously proposed pruning schemes. Highly overparametrized deep neural networks show impressive results on machine learning tasks. However, with the increase in model size comes also the demand for memory and computer power at inference stage--two resources that are scarcely available on low-end devices. Pruning techniques have been successfully applied to remove a significant fraction of the network weights while preserving test accuracy attained by dense models. In some cases, the generalization of compressed networks has even been found to be better than with full models (Han et al., 2015; 2017; Mocanu et al., 2018). The sparsity of a network is the number of weights that are identically zero, and can be obtained by applying a sparsity mask on the weights.