Analog compute
Beginner
Doing math with electricity that can be at any level, not just on or off. For example, flows of electricity add up in a wire.
Novice
Representing numbers as physical quantities (voltage, current, charge, time) and letting physics do the arithmetic: currents add where wires meet, charge spreads across capacitors. Cheap at low precision, but noise and mismatch limit accuracy.
Expert
Energy efficient below roughly 8 bits of required SNR, where structural simplicity beats digital logic; above that, noise makes each extra bit cost about 4× the energy. Needs converters at the digital boundary.
Explained in Sparsity, in-memory and analog compute (Architectures).
See also: Compute-in-memory (CIM), ADC (analog-to-digital converter).