I have a big problem and i can't manage it. I developed the attached differential equation system and I solved it with 2 different time domains: one of 100 seconds and the other with 500 seconds. If I plot the result of boh analysis on the first 100 seconds I get different results. I'm aware that the problem can be in the time interval choosed by the program, but I don't know if taking small time integration surely lead to correct results. The use of a fixed step method led to aliasing problems that I've just verified. I've also tried to use WorkingPrecision but without improvements.
I realize that the file is quite complex so I really thank you in advance and I will be grateful to anyone who responds.
(the "intchop" cited in the file are lists of constants)