1. An input data processing method implemented in a multiprocessor data processing system, said multiprocessor data processing system comprising a plurality of cascaded modules, each of said cascaded modules comprising: a data processing unit connected to other data processing units in immediately adjacent downstream and upstream modules by means of a communication network, a first memory for storing data, an additional processing unit, a second memory for storing data associated with said additional processing unit, a programmable logic cell array configurable into first, second, third and fourth input/output interfacing means for temporarily memorizing data into memorized data, and into a central processing and switching means for processing said memorized data into processed data and switching said processed data towards one of said input/output interfacing means, a first module bus for interconnecting said data processing unit, said first memory and said first input/output interfacing means, and a second module bus for interconnecting said additional processing unit, said second memory and said fourth input/output interfacing means, said second and third input/output interfacing means in said each of said cascaded modules being interconnected to the third input/output interfacing means in said immediately adjacent upstream module and the second input/output interfacing means in said immediately adjacent downstream module, by two intermodular buses, respectively, said second and third input/output interfacing means respectively in said programmable logic cell array of a last module and a first module in said plurality of said cascaded modules being connected by means of a feedback bus, said input data processing method comprising: a first step further consisting in loading a respective set of matrix multiplication weights into said second memory of each of said cascaded modules via said communication network and said input data into said first memory of said first module, and at least one set of second and third steps in each of said cascaded modules, said second step consisting in carrying out partial processings on said input data in said additional processing unit of said each cascaded module as a function of said respective set of matrix multiplication weights for determining partial data, and said third step consisting in downloading said partial data to any one of said programmable logic cell arrays or any one of said first and second memories in said cascaded modules via said intermodular buses and said feedback bus.