#8321: numerical integration with arbitrary precision
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   Reporter:  burcin           |       Owner:  burcin              
       Type:  defect           |      Status:  needs_review        
   Priority:  major            |   Milestone:  sage-4.5.3          
  Component:  symbolics        |    Keywords:  numerics,integration
     Author:  Stefan Reiterer  |    Upstream:  N/A                 
   Reviewer:                   |      Merged:                      
Work_issues:                   |  
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Changes (by newvalueoldvalue):

 * cc: fredrik.johansson (added)
  * keywords:  => numerics,integration
  * author:  => Stefan Reiterer


Comment:

 Thank you for the patch Stefan. This was much needed for quite a while
 now.

 Replying to [comment:10 maldun]:
 > Replying to [comment:8 kcrisman]:
 > > Thanks, Maldun, this is a good addition to have.  I don't have time to
 review this immediately, but it would be helpful to know if you detected
 any errors, compared this with symbolic integrals and their evaluation,
 etc.  Basically, that the results from this really are as accurate as
 advertised.

 I agree. I like how the patch looks overall. It would be good to see
 comparisons on
  * error margins
  * speed

 Maybe Fredrik can comment on this as well.

 Using `fast_callable()` for `mp_f` could help improve the speed.

 Does anyone know of good examples to add as tests for numerical
 integration?

 > > Also, you might as well leave the GSL stuff in as comments, as in the
 patch you posted above, or even as an optional argument, though that may
 not be compatible with `_evalf_` elsewhere...

 Unfortunately, ATM, the numerical evaluation framework for symbolic
 expressions doesn't support specifying different methods. This could
 (probably, I didn't check the code) be done by changing the interpretation
 of the python object we pass around to keep the algorithm parameter and
 the parent, instead of just the parent. Is this a desirable change? Shall
 we open a ticket for this?

 > I will consider this, but hopefully it is not necessary, and mpmath will
 do the whole thing.
 > If I understood that right, burcin wants to change the numerical
 evaluation completly to mpmath, because it supports arbitrary prescision.

 I guess this is based on a comment I made in the context of orthogonal
 polynomials and scipy vs. mpmath. Instead of a general policy, I'd like to
 consider each function separately.

 Overall, I'd lean toward using `mpfr` if it supports the given function.
 Otherwise, choosing between `pari`, `mpmath`, etc. can be difficult, since
 on many examples one implementation doesn't beat the other uniformly for
 different precision or domains.

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8321#comment:12>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
and MATLAB

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