1. A calculation processing apparatus for executing a network calculation by a network configured by connecting a plurality of logical processing nodes, the apparatus comprising: a calculation unit configured to calculate respective sizes of buffers used to hold calculation result data by the plurality of processing nodes required, said calculation unit performing such a calculation for each buffer assignment method of a plurality of buffer assignment methods of assigning memory areas as buffers, on the basis of a configuration of the network; a selection unit configured to select one of the plurality of types of buffer assignment methods based on the respective sizes required for each of the plurality of buffer assignment methods calculated by said calculation unit; and an execution unit configured to control the respective processing nodes to execute calculations in the network calculations using the buffers assigned by the buffer assignment method selected by said selection unit.