Abstract
After having reviewed the RETARD code, which was originally written by Hairer & Wanner in 1995 with the aim of solving delay differential equations (DDEs), a new arithmetic called OSFESOR code is presented in this paper. The OSFESOR (Optimal stepsize for each step of RETARD) code is a tool for automatic implementation of DDEs in Fortran 77. Consequently, by use of the OSFESOR code, it is possible during the run of a program to evaluate the solution of DDEs with optimal stepsize, H, for each step , to evaluate the accuracy of any result provided by the computer . In short, the use of OSFESOR code serves to validate the result provided by a computer, and to assure the user of the reliability of scientific computations.
