An inference task is performed using a computation device having a plurality of processing elements operable in parallel and connected via a connectivity system. Performing the task includes accepting at the device a specification of at least part of the inference task. The specification characterizes a plurality of variables and a plurality of factors, each factor being associated with a subset of the variables. Each of the processing elements is configured with data defining one or more of the plurality of factors. At each of the processing elements, computation associated with one of the factors is performed concurrently with other of the processing elements performing computation associated with different ones of the factors. Messages are exchanged via a connectivity system. The messages provide inputs and/or outputs to the processing elements for the computations associated with the factors and provide a result of performing of the at least the part of the inference task.