The Garin–Lowry model is a well-documented spatial interaction model which does, however, leave unanswered questions that relate to the constraint procedure and the supply component. The incorporation of a stock simulation model satisfies both these limitations and if the iterative structure is reformulated the whole is capable of automatic calibration. This paper concentrates on the issue of automatic calibration by presenting a framework within which existing search algorithms can be incorporated, and presents the results of such a calibration and a subsequent run of the model using the automatically derived values for the parameters.