This paper presents comprehensive empirical analysis challenging gradient sparsity assumptions in Differentially Private Federated Learning. Experiments reveal common assumptions don't hold: MLPs exhibit higher sparsity than CNNs, sparsity decreases during training, and higher sparsity doesn't correlate with better performance. These findings challenge sparsity-based compression foundations in DP-FL, highlighting need for nuanced, adaptive compression strategies accounting for architecture differences, training dynamics, and threshold sensitivity.
sumit sah (Sun,) studied this question.