Implementation of the two-point ray tracing algorithm into the Fortran 77 subroutine package CRT, its numerical stability and performance were of the highest priority in the last years. We are far from stating that the problem is solved once for ever. Nevertheless, the progress reached is not negligible.
This brief study is devoted to the numerical tests and comparisons of three different versions of the two-point ray tracing code, demonstrating just the evolution of the code in last three years. The versions are dated to the years 1994, 1996 and 1997. The tests were performed in models L7 and DOM.
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