From: Peng Yu <pengyu.ut@gm...>  20130621 22:17:01

Hi Arthur, First. I want to thank you for your long and detailed reply. Here are some of my thoughts, which others may or may not agree. But that is OK. > OK! I am afraid that I can not change how sourceforge arranges its forums > etc, but discussion here can be of interest to developers so you are > welcome! My impression is that github is much better than sourceforge (faster, easier for collaboration, more people are using it, I've seen a number of projects migrate from sf to github but the other way around). Therefore, github is a better repository than sf for the purpose of attracting more developers and make the > > (but the gui is bad, it fa. > Sorry you do not like that. There are a range of ways you can help there! > The most extreme would be by working on a new GUI that you liked better  > the fact that Reduce is open source means you have access to pretty much all > you need to do that! Less extreme would be if there were MODEST changes to > what there is now that you believe might make a useful move in the right > direction. I say "modest" changes because I very definitely know how much > time and effort it takes to do anything in that direction. I have a > reimplementation of the GUI code for the CSL version of Reduce as one of my > projects that is at present stalled but when/if I ever get back to it or if > somebody else joins in and moves things forward it would be good to know > what users would like. Please note that explaining things in terms that > could relate to actually implementing something is liable to be a lot more > liable to influence things that high level statements of what is desirable > that do not map neatly onto implementation projects, and stepwise ways to > move from where we are to a better world may be easier to digest than a > "throw it all away and do something different"! > > > >> There are recent papers using it. But it is Mathematica is more used. >> Has anybody compared the pros and cons of reducealgebra vs >> Mathematica? (I don't find a comparison.) Thanks. > > > I think that different people are motivated by very different aspects of the > two systems. Here is my start at a few thoughts, but note very well that > somebody employed by Mathematica or Maple, or working on Axiom, or who had > used Maxima for years and years would put things differently (and could > still be right!). You specifically ask about Mathematica but I may raise > points that put Reduce in a broader context of other systems too... > > (1) If you are employed in some companies or work in some universities you > may not personally have to pay for your software. You may choose only to > collaborate with others who do not have budget constraints. But some algebra > systems cost money and others do not. If a student starts using Reduce while > studying they do not suddenly have to pay once they graduate. This issue is > irrelevant to some users but matters a lot to others! > > (2) If you pay for your algebra system you hope that the supplier will > provide support in all sorts of ways. If you fetch something that is open > source then the help from the developers is not something you can count on > 100%. But if you find a bug then with a commercial offering you can report > it but then may need to wait until a patch or a new version is released. > With open source at least in principle you can inspect the source code and > track down issues for yourself and fix then. An extreme stance taken by some > is that they will not trust a result where they can not see all the steps to > it (hence they will view any results from a closed source system as > unverifiable and hence scientifically indefensible). Others will not feel > happy unless they are using something with paid for support (even if they do > not do a careful assessment of the frequency with which things are fixed for > them). > > (3) Mathematica (in particular) emphasises a useinterface with graphing and > a load of other stuff fully integrated. If you need that sort of stuff then > you need something other than Reduce. Some people do and others just want to > compute algebraic results  and for them the notebook stuff and graphing > capability of Mathematica (or Maple... etc) is not central to what they need > of an ALGEBRA system. > > (4) Some users need an algebra system for what I will describe as "general > algebra". Eg almost any use in highschool or at undergraduate level is > liable to be like that. Any of the full systems is liable to do what they > need (maybe)???? Others have special needs and so some particular systems > might thus suit them best. Let me list some things I think are strengths of > and then weaknesses of Reduce so you can see that for SOME people these may > be special reasons to go one way or the other: > (a) Maybe all of the "redlog" parts of Reduce are respectably > cutting edge tools for solving the sorts of problem that they > address? If you need that then you should probably take Reduce > jolly seriously! > (b) If you want to embed an algebra system within your existing > or future product then Reduce is a sane candidate to look at > rather carefully, and has been evaluated or adopted by a number > of people in the past. > (c) It may be that the Reduce origin in high energy physics makes it > a useful tool for those keen on noncommutating algebra. Each of > the various "loadable packages" in Reduce can represent a unique > selling point for some users! > (d) If you develop a new package for Reduce it can go out to the world > free of charge. Do you like that or do you view that as a problem? > There are things that some other systems do better that Reduce! > (a) Integration involving special functions is done better elsewhere. > There are plans for a big upgrade to Reduce on that front but no > timetable. > (b) Branch cuts and multivalues functions are a menace  and in general > Reduce is not at the forefront of getting them right. Some other > systems are better at letting the user note that some values should > be positive or negative or nonzero or whatever. > (c) Mathematica will explain that it can do EVERYTHING. Graph theory, > number theory, group theory and probability (etc etc), and if you > count the number of builtin or library capabilities it has then it > beats Reduce easily. If you ever need any of those things! > (d) As we mentioned before, the Reduce interface to the user is > such as to try to get the job done. It has not benefitted from > hundreds of manyears of refinement to make it beautiful. That > really matters to some people. > (e) If you are working in some special domain then there may be > specialist software that will serve you much better than any of the > general purpose packages! > > You can find comparisons of systems based on just what coverage of > capabilities they have. Eg the 1999 paper > http://math.unm.edu/~wester/cas_review.html > is something to chew on if you have not found it already. Of course ANY such > report gets out of date after a few years, and for any particular user there > is a BIG issue of what capabilities they need, since my belief is that most > people have their own limited range of uses. > > Mathematica makes a pitch for itself on its website, eg > http://www.wolfram.com/products/mathematica/analysis/content/ComputerAlgebraSystems.html > which naturally explains how good it is and how it will solve all your > problems. > > I then look at what Wikipedia reports, which is > > "Mathematica is proprietary software restricted by both copyright law and > trade secret. > A regular singleuser license for Mathematica used in a commercial > environment costs $2495 although new customers can purchase the "Starter > Edition" for $995. They include eight additional kernels for parallel > computations and one year of service that includes updates, technical > support, a home use license, a webMathematica Amateur license, a Wolfram > Workbench license and three Mathematica Player Pro licenses. Discounts are > available for government, charity, educational, precollege, school, > student, home use and retiree use and depend on geographical region. Student > licenses cost $140. A general "home use" license ("Mathematica Home > Edition") is also available to the public and is priced at $295. Educational > site licenses allow use by students at home. A license manager similar to > FLEXnet is available to provide sharing of licenses within a group." > > and if they could NOT make a compelling argument that they had a bunch of > features makiing them better that Reduce (which you can download for free > and see all the source code for) then something would be seriously amiss. > The only two questions for an individual or which of the rungs of the > Mathematica pricing ladder might apply to them and whether one of the (many) > extra features Mathematica offers is important enough to them to justify the > cost (remembering that in some cases the license you buy will expire after a > while). Some people will jump one way some the other! > > I hope that some who favour Reduce will join us in trying to keep its > existing capabilities up to date and in adding new refinements! > >> >>  >> Regards, >> Peng >> > Arthur  Regards, Peng 