in automated exchange system , a matching unit is supplemented with a calculation unit and a global memory accessible by both the calculation unit and the matching unit . this computer architecture makes it possible to perform some of the calculations related to the volume and / or prices of the baits needed in the matching to be performed in advance . the matching process uses the values resulting from the pre - calculation when needed , and since no or few calculations are done in the matching unit , the process of matching combination contracts can be performed at a higher rate , thereby significantly improving the performance of the matching process . the provision of one or several calculation units makes it possible to perform very complex calculations since many calculations need not be performed in real time .