#11590: Integrating the sgn() function can produce incorrect results
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   Reporter:  mjo       |          Owner:  burcin                               
         
       Type:  defect    |         Status:  new                                  
         
   Priority:  major     |      Milestone:                                       
         
  Component:  calculus  |       Keywords:                                       
         
Work_issues:            |       Upstream:  Reported upstream. Developers 
acknowledge bug.
   Reviewer:            |         Author:                                       
         
     Merged:            |   Dependencies:                                       
         
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Comment(by nbruin):

 Replying to [comment:3 kcrisman]:
 > Even with #11483, this isn't working right.  It should, though - see
 Barton's post at the Maxima ticket:
 > {{{
 > By the way:
 >
 > (%i4) load(abs_integrate)$
 >
 > Correct antiderivative:
 >
 > (%i5) 'integrate(x*signum(x^2-1/4),x);
 > (%o5) abs(x^2-1/4)/2
 >
 > Correct definite integral
 >
 > (%i6) 'integrate(x*signum(x^2-1/4),x,-1,0);
 > (%o6) -1/4
 > }}}
 > so I'm not sure why this is still returning the "wrong" thing.
 Did you try it with `integrate` rather than `'integrate`? Given what we've
 seen elsewhere in this ticket, I suspect it still gives the wrong answer.
 In sage, we are interfacing with `integrate`. If that is still broken,
 then the bug is not fixed as far as sage is concerned.

 If maxima's position is that we should use a different integration routine
 (i.e., `'integrate`) then we need a heuristic on when to use what routine
 ... isn't it maxima's job to figure this out?

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11590#comment:13>
Sage <http://www.sagemath.org>
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