Math & Science ⇒ Best package/environment for calculations

[PMouse]

I'm not brand new to TeX, but I want do start doing more complicated things. I've been looking at techniques for having TeX do calculations, rather than me having to do them in an external tool and then type in the result. But there are too many different ways to do it. I don't know which to choose or how to choose one to start learning.

My current application is just doing Physics/Math homework where I typeset the equations in TeX and then, sometimes, have actual numbers to plug into the final equation. It would be great if I could just copy the equation environment line, tell LaTeX the value of variables, and have LaTeX do the final calculation. But, if I have to rewrite the line, that's okay.

What do you suggest I start learning if I want to be able to do this and more complicated things down the road?

I've tried fp, xint, and l3fp, already, in fact. fp worked okay, but is poorly documented and I actually gave the wrong result in once case and I couldn't figure out why. xint is pretty nice, and seems to be well documented, but latex crashed when I tried to create a constant value in my personal .sty file, like pi, and it seems to be unable to calculate exponents < 1. l3fp sounds like a good one, but I couldn't getting it to work at all, although I gave it the least effort, to be fair. I haven't tried pgfmath, but I think I will, next. I love TikZ.

[Johannes_B]

I am not really a fand of letting LaTeX do rather complex calculations. It just isn't meant to do the job.
Lua might be more suited and can be combined with LaTeX, see LuaLaTeX.

Letting a program calculate and input the result on the spot can be dangerous. Consider the following example

Test series B showed good result, only 17.000 mice died which is 170\,% of the whole population, whereas series B showed the disappointing amount of 13 dead mice. That is an incredible .13\,% of the population.

If you are looking for a cure to some desease ... Looking for a weapon of mass destruction? You achieved to kill 170\,% of something, congratulations, special badge crazy scientist unlocked. Typos can happen to everyone, leading to crazy results.


As you may notice, no, i am really not a fan of that stuff.

[Stefan Kottwitz]

Besides pgfmath, there's tikzmath.

I would also consider LuaTeX for calculating.

Stefan

[PMouse]

Interesting. Thanks for the tip. I'll read up on Lua.

If I end up agreeing with you, that the TeX build env is the wrong tool, how might I construct an alternative scheme? Say I do the calculation externally. Then, what is the best way to give TeX the results for type setting? Do others have something like this working, already?

For argument's sake, let's take the case of making exams with randomly chosen problem parameters and solutions with calculated values. This is one scenario I already know I want to tackle. How should I do this?

I can imagine having each calculated value in a separate file, somewhere, and then importing each file in TeX. That seems a little clunky; I'd have to design and maintain the filename scheme and import them, individually, at the right place, which would make eq environments ugly, if I understand how that would work. Or, maybe I could have one imported file with a macro for each calculated value; but this seems even worse since I'd have to make the calculation program output TeX syntax. (This is why I figure TeX should do it.)

[Stefan Kottwitz]

Here's a heavy math example with Lua: Weierstrass function with pgfplots.

In your case it can be much simpler.

There's also Python-TeX which could be used.

Stefan