Disable abs_integrate

[roed314]

Maxima's abs_integrate contributed package gives us lots of nice new integrals, but also really breaks a lot of stuff, apparently. Add to this list as you see fit:

• Incorrect integral in Maxima #13733 Incorrect integral in Maxima
• Integrating the sgn() function can produce incorrect results #11590 Integrating the sgn() function can produce incorrect results
• cosh integral incorrect because of abs_integrate #14591 cosh integral incorrect because of abs_integrate
• integrate() problem #16643 integrate() infinite loop
• Yet another abs_integrate trig integral problem #17183 Yet another abs_integrate trig integral problem
• Strange integration error/hang with log(abs(sin(x))) #17468 Strange integration error/hang with log(abs(sin(x)))
• Get integral of abs(sin(x)) and abs(cos(x)) right #17511 Get integral of abs(sin(x)) and abs(cos(x)) right
• unsolved piecewise integrals metaticket #17910
• Wrong integration of abs(sin(x)*cos(x)) #23271
• integrate(sqrt(1-4*sin(x)^2),x) is wrong #24117
• This is also blocking update to maxima 5.42, Update maxima to 5.42.2 #26625

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Old:

Can someone more knowledgeable about using maxima for integration determine what the right warning to show is and when to show it? See #12691 for what a stopgap is.

CC: @nbruin @orlitzky @kcrisman @pjbruin @rwst @paulmasson @mforets

Component: calculus

Keywords: abs_integrate

Author: Ralf Stephan, Frédéric Chapoton

Branch: b5c9cc5

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/12731

[kcrisman]

comment:1

I'm not really sure that this is appropriate for a stopgap. I mean, unless we put in a catch for the specific form like integrate(x * sgn(x^2 - 1/4), x, -1, 0), we would have to put in a stopgap for the entire integration, which is ridiculous.

Unless we checked for the signum function with nonlinear operands in it sometime... but that's more than I have time to parse now.