Instant Complexity Reduction in CNNs using Locality-Sensitive Hashing
Lukas Meiner Jens Mehnert Alexandru Paul Condurache
To reduce the computational cost of convolutional neural networks (CNNs) for
usage on resource-constrained devices, structured pruning approaches have shown
promising results, drastically reducing floating-point operations (FLOPs)
without substantial drops in accuracy. However, most recent methods require
fine-tuning or specific training procedures to achieve a reasonable trade-off
between retained accuracy and reduction in FLOPs. This introduces additional
cost in the form of computational overhead and requires training data to be
available. To this end, we propose HASTE (Hashing for Tractable Efficiency), a
parameter-free and data-free module that acts as a plug-and-play replacement
for any regular convolution module. It instantly reduces the network's
test-time inference cost without requiring any training or fine-tuning. We are
able to drastically compress latent feature maps without sacrificing much
accuracy by using locality-sensitive hashing (LSH) to detect redundancies in
the channel dimension. Similar channels are aggregated to reduce the input and
filter depth simultaneously, allowing for cheaper convolutions. We demonstrate
our approach on the popular vision benchmarks CIFAR-10 and ImageNet. In
particular, we are able to instantly drop 46.72% of FLOPs while only losing
1.25% accuracy by just swapping the convolution modules in a ResNet34 on
CIFAR-10 for our HASTE module.