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I'm playing with FriCAS in sandbox and the problem is, When asked to find indefinite integral (as well as in many other cases), FriCAS outputs auto-generated variables in a rather unsightly manner, for example,

integrate(x^x, x)

outputs $\int_{}^x\%A^{\%A}\mathbb{d}\%A$ which is quite ugly.

The question is, is there a way to prettify the output? How can I substitute $\%A$ with $t$, for example?

Thehx
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1 Answers1

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Okay, so I contacted the guys at the fricas google group, as IV_ suggested in his comment to the question. Thanks again for pointing me there!

Waldek Hebisch posted the following code that solves my problem:

)expose OutputFormTools

subst_of(f, ls, lf) ==
    symbol?(f) =>
        s := symbol(f)
        k := position(s, ls)
        k > 0 => lf(k)
        f
    atom?(f) => f
    la := arguments(f)
    nla := [subst_of(fi, ls, lf) for fi in la]
    construct(operator(f), nla)$OutputFormTools

It would perform the necessary dummy variable substitution when used like this:

iif := integrate(x^x, x)::OutputForm;
subst_of(iif, [%A], [t])

Which will produce a much cleaner answer, $\int_{}^{x}t^t\mathbb{d}t$, and that was precisely what I was looking for.

Thehx
  • 183