Implicit parallelism computing is an active research domain of computer science. Most implicit parallelism solutions, to solve partial differential equations and scientific simulations, are based on the specificity of resolution methods where the user has to call specific functions which embed parallelism. This paper presents the parallel implicit library SkelGIS which allows the user to freely write its resolution method in a sequential programming style in C++. This library relies on four concepts that are applied to the specific case of network simulations. SkelGIS is evaluated on the real-case simulation of the blood-flow in an arterial network. Benchmarks have been performed to compare the SkelGIS simulation to an OpenMP code and to show its scalability on a cluster using 1024 cores.