Script to replace "a^b" in an expression with "pow(a,b)"

[Ramo]

I have a few beastly mathematical expressions that I need to use in C++, but I got it from Maple. Maple uses "^" as the exponentiation operator, incompatible with C (which uses pow().

So, I need a script to go from a^b to pow(a,b).

For instance, here's one of them:

1/12/d/k/tan(b)/a*((6*sqrt(3)*r*sqrt(-k^4*a^4-a^4*d^4*tan(b)^4*k^2-2*a^4*d^2*tan(b)^2*k^3+4*k^3*a^3*r*tan(b)^2-4*k^2*a^2*r^2*tan(b)^4-2*a^4*tan(b)^4*d^2*k^2+4*a^3*tan(b)^4*k^2*r-2*a^4*tan(b)^2*k^3-a^4*tan(b)^4*k^2+4*a^3*d^2*tan(b)^4*k^2*r-16*r*k^4*d*tan(b)^2*a^2+k^3*a^4+a^4*tan(b)^6+3*a^4 *tan(b)^6*d^2+a^4*d^6*tan(b)^6-8*a*r^3*tan(b)^6+3*a^4*tan(b)^2*k^2+12*a^2*tan(b)^ 6*r^2-6*a^3*tan(b)^6*r+3*a^4*tan(b)^6*d^4-12*a^3*d^2*tan(b)^4*k*r+3*a^4*d^2*tan(b)^2*k^2-12*a^3*tan(b)^6*d^2*r+6*a^4*tan(b)^4*d^2*k+12*a^2* d^2*tan(b)^6*r^2+27*r^2*tan(b)^4*d^2*k^2+3*a^4*d^4 *tan(b)^4*k-6*a^3*d^4*tan(b)^6*r+12*k*a^2*r^2*tan(b)^4-6*k^2*a^3*r*tan(b)^2-12*a^3*tan(b)^4*k*r+18*r*d*k^2*tan(b)^4*a^2+18*r*d ^3*k^2*tan(b)^4*a^2+18*r*d*k^3*tan(b)^2*a^2-36*r^2*d*k^2*tan(b)^4*a+3*a^4*tan(b)^4*k)*d*k*tan( b)^2+k^3*a^4+a^4*tan(b)^6+3*a^4*tan(b)^6*d^2+a^4*d ^6*tan(b)^6-8*a*r^3*tan(b)^6+3*a^4*tan(b)^2*k^2+12*a^2*tan(b)^ 6*r^2-6*a^3*tan(b)^6*r+3*a^4*tan(b)^6*d^4-12*a^3*d^2*tan(b)^4*k*r+3*a^4*d^2*tan(b)^2*k^2-12*a^3*tan(b)^6*d^2*r+6*a^4*tan(b)^4*d^2*k+12*a^2* d^2*tan(b)^6*r^2+54*r^2*tan(b)^4*d^2*k^2+3*a^4*d^4 *tan(b)^4*k-6*a^3*d^4*tan(b)^6*r+12*k*a^2*r^2*tan(b)^4-6*k^2*a^3*r*tan(b)^2-12*a^3*tan(b)^4*k*r+18*r*d*k^2*tan(b)^4*a^2+18*r*d ^3*k^2*tan(b)^4*a^2+18*r*d*k^3*tan(b)^2*a^2-36*r^2*d*k^2*tan(b)^4*a+3*a^4*tan(b)^4*k)*a^2)^(1/3)-1/12*(12*r*k^2*d*tan(b)^2+a^2*tan(b)^4+2*a^2*tan(b)^ 4*d^2+2*a^2*tan(b)^2*k-4*a*tan(b)^4*r+a^2*d^4*tan(b)^4+2*a^2*d^2*tan(b)^2 *k-4*a*d^2*tan(b)^4*r+k^2*a^2-4*k*a*r*tan(b)^2+4*r^2*tan(b)^4)/k/d/tan(b)*a/((6*sqrt(3)*r*sqrt(-k^4*a^4-a^4*d^4*tan(b)^4*k^2-2*a^4*d^2*tan(b)^2*k^3+4*k^3*a^3*r*tan(b)^2-4*k^2*a^2*r^2*tan(b)^4-2*a^4*tan(b)^4*d^2*k^2+4*a^3*tan(b)^4*k^2*r-2*a^4*tan(b)^2*k^3-a^4*tan(b)^4*k^2+4*a^3*d^2*tan(b)^4*k^2*r-16*r*k^4*d*tan(b)^2*a^2+k^3*a^4+a^4*tan(b)^6+3*a^4 *tan(b)^6*d^2+a^4*d^6*tan(b)^6-8*a*r^3*tan(b)^6+3*a^4*tan(b)^2*k^2+12*a^2*tan(b)^ 6*r^2-6*a^3*tan(b)^6*r+3*a^4*tan(b)^6*d^4-12*a^3*d^2*tan(b)^4*k*r+3*a^4*d^2*tan(b)^2*k^2-12*a^3*tan(b)^6*d^2*r+6*a^4*tan(b)^4*d^2*k+12*a^2* d^2*tan(b)^6*r^2+27*r^2*tan(b)^4*d^2*k^2+3*a^4*d^4 *tan(b)^4*k-6*a^3*d^4*tan(b)^6*r+12*k*a^2*r^2*tan(b)^4-6*k^2*a^3*r*tan(b)^2-12*a^3*tan(b)^4*k*r+18*r*d*k^2*tan(b)^4*a^2+18*r*d ^3*k^2*tan(b)^4*a^2+18*r*d*k^3*tan(b)^2*a^2-36*r^2*d*k^2*tan(b)^4*a+3*a^4*tan(b)^4*k)*d*k*tan( b)^2+k^3*a^4+a^4*tan(b)^6+3*a^4*tan(b)^6*d^2+a^4*d ^6*tan(b)^6-8*a*r^3*tan(b)^6+3*a^4*tan(b)^2*k^2+12*a^2*tan(b)^ 6*r^2-6*a^3*tan(b)^6*r+3*a^4*tan(b)^6*d^4-12*a^3*d^2*tan(b)^4*k*r+3*a^4*d^2*tan(b)^2*k^2-12*a^3*tan(b)^6*d^2*r+6*a^4*tan(b)^4*d^2*k+12*a^2* d^2*tan(b)^6*r^2+54*r^2*tan(b)^4*d^2*k^2+3*a^4*d^4 *tan(b)^4*k-6*a^3*d^4*tan(b)^6*r+12*k*a^2*r^2*tan(b)^4-6*k^2*a^3*r*tan(b)^2-12*a^3*tan(b)^4*k*r+18*r*d*k^2*tan(b)^4*a^2+18*r*d ^3*k^2*tan(b)^4*a^2+18*r*d*k^3*tan(b)^2*a^2-36*r^2*d*k^2*tan(b)^4*a+3*a^4*tan(b)^4*k)*a^2)^(1/3)+1/6*(a*tan(b)^2+a*d^2*tan(b)^2+k*a-2*r*tan(b)^2)/k/d/tan(b)+1/2*I*sqrt(3)*(1/6/d/k/tan(b)/a*((6*sqrt(3)*r*sqrt(-k^4*a^4-a^4*d^4*tan(b)^4*k^2-2*a^4*d^2*tan(b)^2*k^3+4*k^3*a^3*r*tan(b)^2-4*k^2*a^2*r^2*tan(b)^4-2*a^4*tan(b)^4*d^2*k^2+4*a^3*tan(b)^4*k^2*r-2*a^4*tan(b)^2*k^3-a^4*tan(b)^4*k^2+4*a^3*d^2*tan(b)^4*k^2*r-16*r*k^4*d*tan(b)^2*a^2+k^3*a^4+a^4*tan(b)^6+3*a^4 *tan(b)^6*d^2+a^4*d^6*tan(b)^6-8*a*r^3*tan(b)^6+3*a^4*tan(b)^2*k^2+12*a^2*tan(b)^ 6*r^2-6*a^3*tan(b)^6*r+3*a^4*tan(b)^6*d^4-12*a^3*d^2*tan(b)^4*k*r+3*a^4*d^2*tan(b)^2*k^2-12*a^3*tan(b)^6*d^2*r+6*a^4*tan(b)^4*d^2*k+12*a^2* d^2*tan(b)^6*r^2+27*r^2*tan(b)^4*d^2*k^2+3*a^4*d^4 *tan(b)^4*k-6*a^3*d^4*tan(b)^6*r+12*k*a^2*r^2*tan(b)^4-6*k^2*a^3*r*tan(b)^2-12*a^3*tan(b)^4*k*r+18*r*d*k^2*tan(b)^4*a^2+18*r*d ^3*k^2*tan(b)^4*a^2+18*r*d*k^3*tan(b)^2*a^2-36*r^2*d*k^2*tan(b)^4*a+3*a^4*tan(b)^4*k)*d*k*tan( b)^2+k^3*a^4+a^4*tan(b)^6+3*a^4*tan(b)^6*d^2+a^4*d ^6*tan(b)^6-8*a*r^3*tan(b)^6+3*a^4*tan(b)^2*k^2+12*a^2*tan(b)^ 6*r^2-6*a^3*tan(b)^6*r+3*a^4*tan(b)^6*d^4-12*a^3*d^2*tan(b)^4*k*r+3*a^4*d^2*tan(b)^2*k^2-12*a^3*tan(b)^6*d^2*r+6*a^4*tan(b)^4*d^2*k+12*a^2* d^2*tan(b)^6*r^2+54*r^2*tan(b)^4*d^2*k^2+3*a^4*d^4 *tan(b)^4*k-6*a^3*d^4*tan(b)^6*r+12*k*a^2*r^2*tan(b)^4-6*k^2*a^3*r*tan(b)^2-12*a^3*tan(b)^4*k*r+18*r*d*k^2*tan(b)^4*a^2+18*r*d ^3*k^2*tan(b)^4*a^2+18*r*d*k^3*tan(b)^2*a^2-36*r^2*d*k^2*tan(b)^4*a+3*a^4*tan(b)^4*k)*a^2)^(1/3)-1/6*(12*r*k^2*d*tan(b)^2+a^2*tan(b)^4+2*a^2*tan(b)^4 *d^2+2*a^2*tan(b)^2*k-4*a*tan(b)^4*r+a^2*d^4*tan(b)^4+2*a^2*d^2*tan(b)^2 *k-4*a*d^2*tan(b)^4*r+k^2*a^2-4*k*a*r*tan(b)^2+4*r^2*tan(b)^4)/k/d/tan(b)*a/((6*sqrt(3)*r*sqrt(-k^4*a^4-a^4*d^4*tan(b)^4*k^2-2*a^4*d^2*tan(b)^2*k^3+4*k^3*a^3*r*tan(b)^2-4*k^2*a^2*r^2*tan(b)^4-2*a^4*tan(b)^4*d^2*k^2+4*a^3*tan(b)^4*k^2*r-2*a^4*tan(b)^2*k^3-a^4*tan(b)^4*k^2+4*a^3*d^2*tan(b)^4*k^2*r-16*r*k^4*d*tan(b)^2*a^2+k^3*a^4+a^4*tan(b)^6+3*a^4 *tan(b)^6*d^2+a^4*d^6*tan(b)^6-8*a*r^3*tan(b)^6+3*a^4*tan(b)^2*k^2+12*a^2*tan(b)^ 6*r^2-6*a^3*tan(b)^6*r+3*a^4*tan(b)^6*d^4-12*a^3*d^2*tan(b)^4*k*r+3*a^4*d^2*tan(b)^2*k^2-12*a^3*tan(b)^6*d^2*r+6*a^4*tan(b)^4*d^2*k+12*a^2* d^2*tan(b)^6*r^2+27*r^2*tan(b)^4*d^2*k^2+3*a^4*d^4 *tan(b)^4*k-6*a^3*d^4*tan(b)^6*r+12*k*a^2*r^2*tan(b)^4-6*k^2*a^3*r*tan(b)^2-12*a^3*tan(b)^4*k*r+18*r*d*k^2*tan(b)^4*a^2+18*r*d ^3*k^2*tan(b)^4*a^2+18*r*d*k^3*tan(b)^2*a^2-36*r^2*d*k^2*tan(b)^4*a+3*a^4*tan(b)^4*k)*d*k*tan( b)^2+k^3*a^4+a^4*tan(b)^6+3*a^4*tan(b)^6*d^2+a^4*d ^6*tan(b)^6-8*a*r^3*tan(b)^6+3*a^4*tan(b)^2*k^2+12*a^2*tan(b)^ 6*r^2-6*a^3*tan(b)^6*r+3*a^4*tan(b)^6*d^4-12*a^3*d^2*tan(b)^4*k*r+3*a^4*d^2*tan(b)^2*k^2-12*a^3*tan(b)^6*d^2*r+6*a^4*tan(b)^4*d^2*k+12*a^2* d^2*tan(b)^6*r^2+54*r^2*tan(b)^4*d^2*k^2+3*a^4*d^4 *tan(b)^4*k-6*a^3*d^4*tan(b)^6*r+12*k*a^2*r^2*tan(b)^4-6*k^2*a^3*r*tan(b)^2-12*a^3*tan(b)^4*k*r+18*r*d*k^2*tan(b)^4*a^2+18*r*d ^3*k^2*tan(b)^4*a^2+18*r*d*k^3*tan(b)^2*a^2-36*r^2*d*k^2*tan(b)^4*a+3*a^4*tan(b)^4*k)*a^2)^(1/3));

I tried doing a find and replace shtick over and over again, but I definitely missed some things.

Any ideas?

[DanS]

What editor are you using? Emacs?

[Ramo]

MS Visual Studio.

But I can use another editor if needed of course...

I should probably just go back and rewrite the program in Fortran which doesn't have this stupid restriction...

[loinburger]

Probably be easier to turn ^ into an operator in C++. Forget how that's done, though.

Or maybe you can only overload operators, not create new ones. I forget offhand, and my C++ blackbook is at work.

Edit: Nevermind, you can't define new operators, you can only overload existing ones. Piece of crap language...

[Kuciwalker]

Problem is, the ^ operator is already defined on numbers and such in C++ - it's the bitwise xor.

[Ramo]

The problem with overloading ^ is the order in which C evaluates * and / in relation to it.

So 2*k^2 will end up being evaluated as (2*k)^2.

[pchang]

s/+\w\^+\w/pow($1,$2)/g;

in a perl script should do the trick
(if this is not the exact line, it comes real close)

edit: added + since your expressions may be more than 1 character long.

[Ramo]

Thanks, I'll try that out.

[Mercator]

That doesn't even remotely cover it, pchang, I'm afraid... See the last use of the ^ in the one Ramo provided, for instance. It's got complex nested expressions. The one you suggested wouldn't even work with "tan(b)^4".

And, um, the one you suggested doesn't work. It should be:
s/(\w+)\^(\w+)/pow($1,$2)/g;

This one works a bit better, it'll also take functions (e.g. "tan(b)") or parenthesized expressions, but it won't work with nested parentheses:
s/(\w+(?:\([^()]*\))?)\^(\w*(?:\(.*?\))?)/pow($1,$2)/g;

That reduces the number of ^ from 794 to 4 in the one in your first post though, so you can reasonably finish it off manually.

[pchang]

I bow to the superior intellect

[Kuciwalker]

WTF is that thing anyway?

[Mercator]

Originally posted by pchang
I bow to the superior intellect

You beat me to mentioning regular expressions though. I didn't mean to be too harsh.

Originally posted by Kuciwalker
WTF is that thing anyway?

I hope you're not talking about that regular expression. I'm wondering what the hell Ramo's monster expressions are.

[Kuciwalker]

I'm talking about Ramo's monster.

[Japher]

s/(\w+(?:\([^()]*\))?)\^(\w*(?:\(.*?\))?)/pow($1,$2)/g;

And to think, that was going be the name of my next DL...

[I Am Jeff]

Why don't you just write a C program to do what you need, to replace a^b with pow(a,b) should be too hard of a program to make.