Selective Path Automatic Differentiation: Beyond Uniform Distribution on Backpropagation Dropout

This paper introduces Selective Path Automatic Differentiation (SPAD), a novel approach to reducing memory consumption and mitigating overfitting in gradient-based models for embedded artificial intelligence. SPAD extends the existing Randomized Automatic Differentiation, proposed by Oktay et al and which draws random paths through the backpropagation graph with matrix injection, by enabling alternative probability distributions on the backpropagation graph, thereby enhancing learning performance and memory management. In a specific iteration, SPAD evaluates and ranks multiple paths within the backpropagation graph. Over subsequent iterations, it preferentially follows these higher-ranked paths. This work also presents a compilation-based technique allowing model-agnostic access to random paths, ensuring generalizability across various model architectures, not restricted to deep models. Experimental evaluations conducted across various optimization functions demonstrate an enhanced minimization performance when employing SPAD. Additionally, deep learning experiments with SPAD notably mitigate overfitting, offering benefits akin to those of traditional dropout methods, but with a concomitant decrease in memory usage. We conclude by discussing the unique stochasticity implications of our work and the potential for it to augment other stochastic techniques in the field.