Didal is a distributed data library that supports development of efficient parallel fragmented programs on distributed memory supercomputers. Fragmented programming is a technology where a parallel program is represented as a collection of pieces of data (data fragments) and computations on these pieces (computation fragments), able to be tuned to the resources of a computing system and automatically provide such facilities as dynamic load balancing. While several tools for fragmented programming exist, Didal aims to get benefits from as being a simple to use C++ library, as being able to produce efficient parallel programs. In this paper we study parallelization with Didal library of RHD3D application for numerical modeling of colliding flows in relativistic hydrodynamics. Results of the parallel program’s efficiency and its comparison with Coarray Fortran implementation are provided.