Hi, On Mon, 12 Nov 2001, Brandon Barker wrote:
I've mailed this list before and have taken the advice obtained from it to write a numerical integration program for some of my needs, and GiNaC seems to be the best way for me to accomplish this. First of all, I have only had Calculus 2, and am just now taking the equivalent of a first semester in Computer Science course using C++ (self study - my high school doesn't offer Comp Science, and I don't know any programmers in my area, so I have to rely on on-line resources - like you people, sorry :-/ ) so this may explain why I found latter parts of the GiNaC tutorial harder to comprehend and also the fact that I'm somewhat new to C/C++ (though I've done a lot of reading, w/o much coding and hacking one tends to forget).
I'm actually attempting to write my first C++ program to do Numerical Integration, but I'm having trouble doing this and I wanted to know if someone could show me the source to a simple program using GiNaC to find the summation (for example) of f(x)=x^2 on the interval [1,2] with n=4 (where n == number of intervals). Of course, a=1, b=2, n=4, and integrand=x^2 should all be variables excepted by the summation function.
Once I find out how to implement something simple like this, I think I'll be well on my way to writing the program. Once I get it finished, I'll put it up on SourceForge (by finished I mean something that works and isn't too embarrassing).
Do you have a good reason why you want to do numerical integration in GiNaC? GiNaC's types are meant for symbolic manipulation and much slower than e.g. the builtin double precision. If you are aiming for higher precision I recommend one of the many quadruple precision libraries to be found out there. If that is still not enough, you might consider working directly with CLN. There is a vast amount of literature on the subject. For a start, I would recommend having a look into Numerical Recipes by Press, Teukolsky, Vetterling and Flannery. May I also point you to the other list where something similar was discussed recently? The thread started with this message by Stefan: <http://www.ginac.de/lists/ginac-devel/msg00265.html>. But maybe your real question was misunderstood? Regards -richy. -- Richard B. Kreckel <Richard.Kreckel@Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>