CapsAcc: An Efficient Hardware Accelerator for CapsuleNets with Data Reuse

Recently, CapsuleNets have overtaken traditional Deep Convolutional Neural Networks (CNNs), because of their improved generalization ability due to the multi-dimensional capsules, in contrast to the single-dimensional neurons. Consequently, CapsuleNets also require extremely intense matrix computations, making it a gigantic challenge to achieve high performance. In this paper, we propose CapsAcc, the first specialized CMOS-based hardware architecture to perform CapsuleNets inference with high performance and energy efficiency. State-of-the- art convolutional CNN accelerators would not work efficiently for CapsuleNets, as their designs do not account for unique processing nature of CapsuleNets involving multi-dimensional matrix processing, squashing and dynamic routing. Our architecture exploits the massive parallelism by flexibly feeding the data to a specialized systolic array according to the operations required in different layers. It also avoids extensive load and store operations on the on-chip memory, by reusing the data when possible. We synthesized the complete CapsAcc architecture in a 32nm CMOS technology using Synopsys design tools, and evaluated it for the MNIST benchmark (as also done by the original CapsuleNet paper) to ensure consistent and fair comparisons. This work enables highly-efficient CapsuleNets inference on embedded platforms.