Distance Computation Based on Coupled Spin-Torque Oscillators: Application to Image Processing.

Recent research on nano-oscillators has shown the possibility of using a coupled-oscillator network as a core-computing primitive for non-Boolean computation. The spin-torque oscillator (STO) is an attractive candidate because it is CMOS compatible, highly integrable, scalable, and frequency and phase tunable. Based on these promising features, we propose an alternative coupled-oscillator-based architecture for hybrid spintronic and CMOS hardware that computes a multidimensional norm. The hybrid system, composed of an array of four injection-locked STOs and a CMOS detector, is experimentally demonstrated. The measured performance is then used as the input to simulations that demonstrate the hybrid system as both a distance metric and a convolution computational primitive for image-processing applications. Energy and scaling analysis shows that the STO-based coupled-oscillatory system has a higher efficiency than the CMOS-based system with an order of magnitude faster computation speed in distance computation for high-dimensional input vectors.