Re: unexpected behaviour of Sum

*To*: mathgroup at smc.vnet.net*Subject*: [mg126573] Re: unexpected behaviour of Sum*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sat, 19 May 2012 05:49:01 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <joq5h8$r20$1@smc.vnet.net> <jot5hm$am0$1@smc.vnet.net> <201205180922.FAA17040@smc.vnet.net>*Reply-to*: murray at math.umass.edu

Send to: suggestions at wolfram.com On 5/18/12 5:22 AM, perplexed wrote: > Thanks to everybody. > > It is surely true I could write a better definition > for my functions (sod was just an example), > but still I do think that this is an imperfection in > the documentation of Sum. > > First of all, this SymbolicSumThreshold option > is never cited in the documentation of Sum. > > In general, there is never a hint to the fact that > Sum will try to sum symbolically in the case of > a definite sum. If I did know, I would have considered > writing a better function. > > On the contrary, in the documentation of Sum I read : > > "If the range of a sum is finite, i is typically assigned a sequence > of values, > with f being evaluated for each one." > > and > > "If a sum cannot be carried out explicitly by adding up a finite > number of terms, > Sum will attempt to find a symbolic result. In this case, f is first > evaluated symbolically." > > With due respect, > I think that maybe a couple of lines should be added to the > documentation at least in the "Possible issues" section. > > > > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**Re: unexpected behaviour of Sum***From:*perplexed <yudumbo@gmail.com>