I'll try to answer both posts at once.
Yes, DaWei, I understand the issues of this problem. I had the program working, but using mostly dynamic allocation. Thus, If I allocated a matrix with
double **H in the
main part of the program and then passed it to function
H2, I think (as you said) the compiler assumed I knew what I was doing. When I changed the allocation to
double H[4][4], I thought the compiler would still understand that. With other languages, that's what would happen.
I wanted, if possible, to change my functions as little as possible, but I understand I'll have to do some pointer arithmetic. No problem with that
.
Harakim, thank you for your ideas. The first two work in this case, but are not general enough for the rest of the code. Yes, the third works in gcc... I was just trying to avoid it (for portability purposes).
I know the code can (must) be changed. I won't, for example, calculate
r*(1-r) so many times (several elements of the matrix are exactly the same). I'll also use logarithms to work with sums rather than multiplications (
r can be really small).
Overall, now I understand the path to follow. All your ideas were most valuable! As a plant breeder, I have some trouble with programming in C... But my code is for an iterative process that can run for
quite some time, so I need it to be fast.
Regards,
Gabriel.