  We numerically study reservoir computing on a spin-torque oscillator (STO)
array, describing the magnetization dynamics of the STO array by a nonlinear
oscillator model. The STOs exhibit synchronized oscillation due to coupling by
magnetic dipolar fields. We show that reservoir computing can be performed
using the synchronized oscillation state. The performance can be improved by
increasing the number of STOs. The performance becomes highest at the boundary
between the synchronized and disordered states. Using an STO array, we can
achieve higher performance than that of an echo-state network with similar
number of units. This result indicates that STO arrays are promising for
hardware implementation of reservoir computing.
