Burcin Erocal wrote:
> On Thu, 13 Nov 2008 04:09:56 -0600
> Jason Grout <[EMAIL PROTECTED]> wrote:
> 
>> Burcin Erocal wrote:
>>
>>>
>>> Returning to the question of how Sage plans to handle this, the
>>> short answer is "I am working on it." :) 
>>>
>> Yeah!
>>
>>
>>> We will have a completely new implementation of summation,
>>> independent of the one in Maxima. At the moment I have an
>>> implementation of the theoretical framework which lets you solve
>>> much more complicated sums than the ones above. Unfortunately,
>>> coming up with an interface that spares the user from the gory
>>> details of the theory will still be a challenge. Thus, it will be
>>> some time before these problems are handled natively in Sage, but
>>> then Sage will (hopefully) be more capable than the others out
>>> there. 
>>
>> Is there any chance you could make this work available so people
>> could experiment with it, test it, and if desired, give suggestions
>> for an interface?  On the other hand, I understand if the work is
>> still at a "I need to work on this alone" stage.
> 
> In this case, there is a huge gap between theory and the user. It
> is not like giving the ratio of the consecutive terms of your
> summand as an argument to Gosper's algorithm. Unless you want to get
> into research in this area, the code is useless for now.
> 
> Nevertheless, I will start implementing a simple user interface,
> which I hope will help me handle more complex expressions as
> well. After I have the basic framework to construct the algebraic
> objects I work with, given the symbolic expressions, I will start
> submitting patches.
> 


I would love to see this done in Sage. The few times that I fire up
Maple is using the SumTools Package:

> Introduction to the SumTools Package
> 
> Calling Sequence
> 
>      SumTools[function](args)
> 
>      function(args)
> 
> Description
> 
> The SumTools package contains functions that help find closed forms of
> definite and indefinite sums. The package consists of three functions
> and three subpackages.
> 
> Functions for Computing Closed Forms of Definite and Indefinite Sums
> 
> SumTools[Summation]: compute closed forms of definite and indefinite sums
> 
> SumTools[DefiniteSummation]: compute closed forms of definite sums
> 
> SumTools[IndefiniteSummation]: compute closed forms of indefinite sums
> 
> Tools for Computing Closed Forms of Indefinite sums: The IndefiniteSum
> Subpackage
> 
> SumTools[IndefiniteSum][AccurateSummation]: compute indefinite sums
> using the method of accurate summation
> 
> SumTools[IndefiniteSum][AddIndefiniteSum]: library extension mechanism
> 
> SumTools[IndefiniteSum][Hypergeometric]: compute indefinite sums of
> hypergeometric terms
> 
> SumTools[IndefiniteSum][Indefinite]: compute closed forms of indefinite sums
> 
> SumTools[IndefiniteSum][Polynomial]: compute indefinite sums of polynomials
> 
> SumTools[IndefiniteSum][Rational]: compute indefinite sums of rational 
> functions
> 
> SumTools[IndefiniteSum][RemoveIndefiniteSum]: library extension mechanism
> 
> Tools for Computing Closed Forms of Definite Sums: The DefiniteSum Subpackage
> 
> SumTools[DefiniteSum][CreativeTelescoping]: compute closed forms of
> definite sums using the creative telescoping method
> 
> SumTools[DefiniteSum][Definite]: compute closed forms of definite sums
> 
> SumTools[DefiniteSum][pFqToStandardFunctions]: compute closed forms of
> definite sums using the conversion method where the hypergeometric
> series is used as an intermediate representation
> 
> SumTools[DefiniteSum][Telescoping]: compute closed forms of definite
> sums using the classical telescoping method
> 
> Tools for Working with Hypergeometric Terms: The Hypergeometric Subpackage
> 
> Normal forms of rational functions and hypergeometric terms:
> 
> SumTools[Hypergeometric][MultiplicativeDecomposition],
> SumTools[Hypergeometric][PolynomialNormalForm],
> SumTools[Hypergeometric][RationalCanonicalForm],
> SumTools[Hypergeometric][SumDecomposition]
> 
> Algorithms for definite and indefinite sums of hypergeometric type:
> 
> SumTools[Hypergeometric][ExtendedGosper],
> SumTools[Hypergeometric][ExtendedZeilberger],
> SumTools[Hypergeometric][Gosper],
> SumTools[Hypergeometric][IsZApplicable],
> SumTools[Hypergeometric][KoepfGosper],
> SumTools[Hypergeometric][KoepfZeilberger],
> SumTools[Hypergeometric][LowerBound],
> SumTools[Hypergeometric][MinimalZpair],
> SumTools[Hypergeometric][Zeilberger],
> SumTools[Hypergeometric][ZeilbergerRecurrence],
> SumTools[Hypergeometric][ZpairDirect]
> 
> Applications:
> 
> SumTools[Hypergeometric][DefiniteSum],
> SumTools[Hypergeometric][IndefiniteSum],
> SumTools[Hypergeometric][WZMethod]
> 
> Other functions:
> 
> SumTools[Hypergeometric][AreSimilar],
> SumTools[Hypergeometric][ConjugateRTerm],
> SumTools[Hypergeometric][IsHolonomic],
> SumTools[Hypergeometric][IsHypergeometricTerm],
> SumTools[Hypergeometric][IsProperHypergeometricTerm],
> SumTools[Hypergeometric][Verify]
> 
> Accessing SumTools Package Functions
> 
> Each function in the SumTools package can be accessed by using either
> the long form or the short form of the function name in the command
> calling sequence.
> 
> Getting Help
> 
> To display the help page for a particular SumTools function, see
> Getting Help with a Function in a Package.
> 
> See Also
> 
> LREtools, rsolve, sum, UsingPackages, with
> 
> References
> 
> Abramov, S.A.; Carette, J.J.; Geddes, K.O.; and Le, H.Q. "Symbolic
> Summation in Maple." Technical Report CS-2002-32, School of Computer
> Science, University of Waterloo, Ontario, Canada. (2002).


Jaap


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