A computing system having a computational memory and a method configured to perform computations using an approximate message passing process. The system exploits memcomputing which is a prominent non-von Neumann computational approach expected to significantly improve an energy efficiency of computing systems. The computational memory includes at least one memristive array comprising a plurality of memristive devices arranged in a crossbar topology and the computing system may further comprise digital combinational control circuitry adapted to perform read and write operations on the at least one memristive array and to store at least one state variable of the approximate message passing process. An output of the at least one memristive array represents a result of a computation of the approximate message passing process. The control circuitry may comprise circuitry to iteratively perform computations that may not require high precision.