A hardware-adaptive learning algorithm for superlinear-capacity associative memory on memristor crossbars

The human brain recalls complete patterns from partial cues via associative memory, but Hopfield neural networks emulating this process are inefficient on conventional hardware, and prior memristor-based implementations are vulnerable to device defects and have limited capacity, particularly for continuous patterns. We introduce a hardware-adaptive learning algorithm that incorporates experimentally calibrated device constraints during training and validate it on an integrated memristor crossbar compute-in-memory platform. The approach improves defect tolerance and effective capacity, achieving threefold higher capacity than a pseudo-inverse baseline at 50% stuck-at faults. The same framework extends to scalable multilayer architectures supporting binary and continuous-valued patterns, where we observe superlinear capacity scaling on correlated data (∝N1.49 and ∝N1.74, respectively). Leveraging crossbar parallelism with synchronous updates, the implementation reduces energy by 8.8× and latency by 99.7% for 64-dimensional patterns versus asynchronous schemes. These results provide a practical algorithm-hardware co-design for robust, efficient Hopfield-style associative recall. Human brains can recall memories from incomplete cues via associative memory. He et al. emulates this function using a hardware-adaptive learning algorithm for Hopfield-style recall, validate it on integrated RRAM crossbar, and demonstrate superliner capacity scaling in a multilayer architecture.