  The numerical simulation of the physical systems has become in recent years a
fundamental tool to perform analyses and predictions in several application
fields, spanning from industry to the academy. As far as large scale
simulations are concerned, one of the most computationally expensive task is
the solution of linear systems arising from the discretization of the partial
differential equations governing the physical processes.This work presents
Chronos, a collection of linear algebra functions specifically designed for the
solution of large, sparse linear systems on massively parallel computers
(https://www.m3eweb.it/chronos/). Its emphasis is on modern, effective and
scalable AMG preconditioners for High Performance Computing (HPC). This work
describes the numerical algorithms and the main structures of this software
suite, especially from the implementation standpoint. Several numerical results
arising from practical mechanics and fluid dynamics applications with hundreds
of millions of unknowns are addressed and compared with other state-of-the-art
linear solvers, proving Chronos efficiency and robustness.
