PERSYS - a program for the solution near the origin of coupled channel Schrodinger equation with singular potential. The code PERSYS produces the regular solution of a system of coupled Schrödinger equations near the origin, where the potential exhibits a singularity, due to the centrifugal, spin-orbit and Coulomb components. The solution is calculated by means of a highly accurate method, which consists of a perturbative technique in which the centrifugal term is taken as the reference potential while the rest of terms are seen as a perturbation. (Source: