Networks of superharmonic injection-locked (SHIL) electronic oscillators can be used to emulate Ising machines for solving difficult computational problems. The oscillators can be simulated or implemented in hardware (e.g., with LC oscillators) and are coupled to each other with links whose connection strengths are weighted according to the problem being solved. The oscillators' phases may be measured with respect to reference signal(s) from one or more reference oscillators, each of which emits a reference signal but does not receive input from any other oscillator. Sparsely connected networks of SHIL oscillators and reference oscillators can be used as Viterbi decoders that do not suffer from the information bottleneck between logic computational blocks and memory in digital computing systems. Sparsely connected networks of SHIL oscillators and reference oscillators can also be programmed to act as Boolean logic gates that operate in both forward and backward directions, enabling multipliers that can factor numbers.