hence , the invention is a contribution to the field of designing computer implemented systems that test how different trading algorithms work when fed historic data . it teaches an efficient and effective data representation that comprises two elements . first , an object - based representation of each trading strategy ; each object is instantiated as a ‘ strategy instance ’. secondly , a pairing between any tradable instrument and any strategy instance ; the pairing is called an ‘ account ’. a key advantage of the data representation is that the data in each account is held in a matrix format ; these are easily and efficiently stored in standard relational databases . further , operating the method involves large scale matrix operations , which are fast and computationally efficient within a matrix based language . conventional approaches do not store data in a matrix format and hence fail to achieve the computational efficiency possible with the present invention .