Re: Summation Formulae Table

*To*: mathgroup at smc.vnet.net*Subject*: [mg28447] Re: Summation Formulae Table*From*: "Paul Lutus" <nospam at nosite.com>*Date*: Thu, 19 Apr 2001 03:26:35 -0400 (EDT)*References*: <9bjg2v$gs8@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

"O D" <O_member at newsranger.com> wrote in message news:9bjg2v$gs8 at smc.vnet.net... > Is there a way to access the tables that Sum[] uses to simplify summations into > known functions like for example > > Sum[Exp[-a* n^2], {n, -Infinity, Infinity}] > > is simplified into > > EllipticTheta[3, 0, E^(-a)] This simplification does not use a table, it uses a deterministic algorithm. > > Is there a way to use the table in reverse, to approximate a known function? You need to offer a specific example of a problem and a Mathematica solution that you would like to see in a different form. Also, if you are interested in approximating functions, you may want to approach the problem differently, using regression methods such as are offered by "Fit" and related resources. -- Paul Lutus www.arachnoid.com