Re: Re: v5.2 preferred for stability over v6.0

*To*: mathgroup at smc.vnet.net*Subject*: [mg78143] Re: [mg78066] Re: v5.2 preferred for stability over v6.0*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Sat, 23 Jun 2007 07:23:35 -0400 (EDT)*References*: <200706200941.FAA10388@smc.vnet.net> <f5dh2f$p93$1@smc.vnet.net> <200706221038.GAA14965@smc.vnet.net>

On 22 Jun 2007, at 19:38, David Bailey wrote: > Andrzej Kozlowski wrote: >> In my case both Mathematica 5.2 and 6.0 give exactly the same answer >> for this limit (provided you make the necessary assumptions). So this >> leaves two possibilities. >> >> One is that you have a different version of Mathematica than me. That >> would explain the fact that our experiences are exactly the opposite: >> I find version 6.0 a giant improvement over 5.2 and I find its >> documentation center almost exactly what I have always wanted. >> However, it seems to me highly unlikely that our versions of >> Mathematica 6.0 are different. In which case the only other >> explanation is that for your performance as a debugger you deserve a >> substantial pay cut. >> >> Andrzej Kozlowski >> >> >> On 20 Jun 2007, at 18:41, jrc wrote: >> >>> With my recent experience with the inability of v6 to >>> find a simple limit (easily found with 5.2 and, incidentally, >>> with another system), and reading over the confusion in the posts >>> here recently, I've decided to do any serious analysis with >>> v5.2 instead of v6.0. >>> >>> This seems to be another typical case of *.0 versions full >>> of buggy new ideas with incomplete development. The worst >>> part is the hopelessly misconstructed and unexplained new >>> 'documentation center'. Whatever improvements there are in >>> v6.0 are so incompletely developed, and poorly explained >>> (if at all) as to not be worth the upgrade. >>> >>> Hopefully Wolfram is paying attention, and I would guess >>> that we are the primary debuggers. I, for one, would like >>> a pay increase. >>> >>> jrc >>> >> >> > Andrzej, I don't think those comments are fair. The fact is that > people > build large and complex systems using Mathematica. You don't need many > tiny changes in the behaviour of Mathematica to create havoc for > developers. The effort to reduce a problem to something that can be > presented here can be substantial and nerves can become frayed! > > I myself have spent considerable time recoding certain plots that > worked > fine at 5.2, but have become unbearably slow in 6.0. If they had been > slow at 5.2, I would have accepted that with a shrug and recoded them > accordingly, but it is the change that can be very disruptive. > > I am not saying I agree with JRC, but clearly there are changes and > new > bugs with 6.0, and some people's code is inevitably hit harder than > others on a more or less random basis! > > David Bailey > http://www.dbaileyconsultancy.co.uk > I can't really see what you think was unfair about my comments, or rather, in my opinion, if there was anything unfair than it had little to do with the points you make. I confess I made one mistake - I did not carry out all the steps that JRC did in trying to compute his limit. More precisely, I did not use $Assumptions for the reason that I never use it - in my opinion the global (as opposed to local) assumptions mechanism is one of the few rather daft ideas in Mathematica. Or perhaps, not really daft, but completely unusable for a naturally forgetful person like myself. So when I computed the limit that JRC claimed (quite wrongly) Mathematica could not compute using local assumptions it returned exactly the same answer as in Mathematica 5.2. I then wrongly (or perhaps "unfairly") assumed that JRC did something different in computing the Limit when using version 6 and when using version 5.2. Eventually, as a result of off-line communication with him, I realized that there was something wrong with $Assumptions. But does this limit problem and all the comments that JRC made about Mathematica 6.0 have to do with "people build large and complex systems using Mathematica"?? As far as I can tell now (see the post by Daniel Lichtblau) he found a bug in $Assumptions. He then complained that Mathematica 6.0 could not compute a simple limit that Mathematica 5.2 and another CAS has no problems with. This was manifestly false: Mathematica 6.0 has no problems with this limit provided the right assumption are passed to Limit. Later JRC complained that the new behaviour was not documented. Since it is the result of a bug, how on earth would you expect it to be documented? And then finally, what does this limit problem have to do with all the things in your post? JRC suggested that Mathematica 6.0 was either not worth the upgrade price or (depending on how you interpret his comments) it was not sufficiently debugged before being released and people like himself have to play the role of debuggers. You seem to suggest that you do not agree with him (?) but then what exactly do you agree with? I wrote, ironically, that as a debugger he was not doing a very good job - he claimed that mathematica could not compute a limit which is certainly could easily compute. I also don't agree with a single one of his comments about Mathematica 6.0, in fact I think they were the most unfair comments about a new release of any program I have read in a long time. If you now think this is unfair than perhaps you should explain more clearly what exactly you think about these claim. I don't see how saying that "some people's code is inevitably hit harder than others on a more or less random basis" is relevant. Isn't that true about any major new release? Are you saying the release of v. 6 should have been delayed for another half a year or perhaps longer? Andrzej Kozlowski

**References**:**v5.2 preferred for stability over v6.0***From:*jrc <jrchaff@mcn.net>

**Re: v5.2 preferred for stability over v6.0***From:*David Bailey <dave@Remove_Thisdbailey.co.uk>

**Re: Re: My problem when solving a system of equations**

**Re: Solving a Integral (2)**

**Re: v5.2 preferred for stability over v6.0**

**Re: v5.2 preferred for stability over v6.0**