August 2009 - Pharo-dev - lists.pharo.org

[Pharo-project] What others do [Scheme]

by Ken.Dickey

> (< 0+0i 1+0i) #t > (sqrt -4) +2i ;; note exact 2, not 2.0 [extra credit] > (log -3) ;; known as #ln in Smalltalk 1.0986122886681098+3.141592653589793i > FYI, -KenD

Aug. 12, 2009

Re: [Pharo-project] Extending #< to compare all numbers

by Schwab,Wilhelm K

Ken, My concerns are not with the (representable) numbers in your tests; it is with the many numbers that do not have exact representations, and with those that will contain roundoff error. Please note that I never called "What Every Computer Scientist Should Know About Floating-Point Arithmetic" trivial - in fact, I used the word non-trivial in connection with such things. I gather that $< is very important to you. What is so critical about it? There is probably a way to solve any problem you have without creating problems in the process, such as using a keyword message to do the comparison and keeping complex numbers separate from magnitudes. "Do you really not believe that (0+0i) = 0 ?? Why, such numbers must be imaginary!! ;^)" Try 0+(0.1+0.1+0.1-0.3)i = 0. Is it so clear now? The zero imaginary part is simple for us, but not nearly so clear to a machine. Bill -----Original Message----- From: pharo-project-bounces(a)lists.gforge.inria.fr [mailto:pharo-project-bounces@lists.gforge.inria.fr] On Behalf Of Ken.Dickey Sent: Wednesday, August 12, 2009 4:00 PM To: Pharo-project(a)lists.gforge.inria.fr Subject: Re: [Pharo-project] Extending #< to compare all numbers "Schwab,Wilhelm K" <bschwab(a)anest.ufl.edu> > Floating point is not always what it seems. Hence my comment that IEEE floats get "the wrong answer fast". I have used interval math, continued fractions, and linear fractional transforms (a.k.a. exact reals). I agree that each representation has its challenges. Let's talk for a second about integers. 0 = (0+0i) --> true 1 = (1+0i) --> true 0 < 1 --> true (0+0i) < (1+0i) --> ?? which answer here gives me the least surprise ?? To put it another way (A = a) --> true (B = b) --> true (A < B) --> true (a < b) --> ?? what do you expect to see here ?? > By extension, I argue that > computer-represented complex numbers are not always what they seem, > only more so. Agreements: computers don't do math well. Computers approximate math. We would prefer to get the best approximations possible and be told when we are in deep waters. There are math systems (e.g. using interval arithmetic) which either complain that they can't come up with a sensible answer (all the bits are roundoff error) or go back and recompute with higher precision numeric representations in order to get X digits of correct precision. I am _not_ proposing to make Pharo into such a system. > Intuition resulting from lots of exposure to mathematicians suggests > that they consider this non-trivial but well-known. I don't consider "What Every Computer Scientist Should Know About Floating-Point Arithmetic" trivial -- especially for us non-mathematician users of numbers. [ http://docs.sun.com/source/806-3568/ncg_goldberg.html ] > If I am reading this correctly, defining $< is making a promise we > can't keep, or perhaps we simply should not try. Again, I am using unit tests as a fixed point. I want "if A=a and B=b and A<B then a<b" to work as I expect. I consider anything else to be deeply broken. > If you can find something that claims to produce a sensible ordering of > complex numbers, please post a reference. Â For now, my sense is that such a > thing cannot exist. I posted what I consider a sensible ordering which unit tests the property I care about. It happens to be a total ordering (not that I really care). I can certainly remove Complex>>< from the code, but I deeply dislike breaking basic logic on integers. I would prefer to have something more meaningful than "mathematicians can't agree on a theoretical ordering of complex numbers, so practical logic must fail". Do you really not believe that (0+0i) = 0 ?? Why, such numbers must be imaginary!! ;^) -KenD _______________________________________________ Pharo-project mailing list Pharo-project(a)lists.gforge.inria.fr http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

Aug. 12, 2009

Re: [Pharo-project] Packages that load in Pharo [WAS] [Ann] RFB/VNC fully configurable by code.

by Miguel Enrique CobÃ¡ Martinez

El miÃ©, 12-08-2009 a las 20:17 -0100, Mariano Martinez Peck escribiÃ³: > Miguel created this page: > http://code.google.com/p/pharo/wiki/PackagesTestedInPharo > > so that we can add there all the packages that load (and work) ok in > Pharo. > > I trying to add some but I found a problem: there is a column called > "Package version". I have a same project (for example SqueakDBX) with > several Packages in the same monticello repository. There isn't a > version for a repository, but for a package. So, what should I do if I > have several packages? Maybe, if you are using monticello configurations you can put the .mcm version there, but I think that we shouldn't be so strict with this page, isn't mean to document exactly what versions of each package but to give an overall view about what runs correctly on Pharo. I think that if the version isn't written, nothing bad will happen, the message that the package works will arrive the destination (the collective mind). As I said, the page will be obsolete some time in the future and will be necessary to delete it (so that we don't get wrong information on the wiki as the squeak wiki). If during the initial phases of pharo life bring some motivation to others to port other packages to pharo, that by itself will be worth the effort. This page is a temporal throw away page. -- Miguel CobÃ¡ http://miguel.leugim.com.mx

Aug. 12, 2009

Re: [Pharo-project] Packages that load in Pharo [WAS] [Ann] RFB/VNC fully configurable by code.

by Keith Hodges

Mariano Martinez Peck wrote: > Miguel created this page: > http://code.google.com/p/pharo/wiki/PackagesTestedInPharo > > so that we can add there all the packages that load (and work) ok in > Pharo. > > I trying to add some but I found a problem: there is a column called > "Package version". I have a same project (for example SqueakDBX) with > several Packages in the same monticello repository. There isn't a > version for a repository, but for a package. So, what should I do if I > have several packages? > > Best, > > Mariano > This really isnt going to scale, why not just use universe or sake/packages Keith

Aug. 12, 2009

[Pharo-project] Packages that load in Pharo [WAS] [Ann] RFB/VNC fully configurable by code.

by Mariano Martinez Peck

Miguel created this page: http://code.google.com/p/pharo/wiki/PackagesTestedInPharo so that we can add there all the packages that load (and work) ok in Pharo. I trying to add some but I found a problem: there is a column called "Package version". I have a same project (for example SqueakDBX) with several Packages in the same monticello repository. There isn't a version for a repository, but for a package. So, what should I do if I have several packages? Best, Mariano ---------- Forwarded message ---------- From: Miguel Enrique CobÃ¡ Martinez <miguel.coba(a)gmail.com> Date: 2009/8/12 Subject: Re: [Pharo-project] [Ann] RFB/VNC fully configurable by code. To: Pharo-project(a)lists.gforge.inria.fr El miÃ©, 12-08-2009 a las 18:18 -0100, Mariano Martinez Peck escribiÃ³: > > > What sort of packages should be put there? For example, I am woring in > SqueakDBX and Glorp and both of them work there. However, they are not > dev tools or something like. Thus, I don't understand which type or > packages should be added. Every package that loads and runs ok on pharo. This will motivate to port even more packages. I hope it will be a catalyzer because if we can show that a lot of packages are already running ok on pharo, the stability and maturity of pharo will make it a good platform to base new software and to port software from other smalltalk versions. So, if you have a package that load/runs, please by any means add it. -- Miguel CobÃ¡ http://miguel.leugim.com.mx _______________________________________________ Pharo-project mailing list Pharo-project(a)lists.gforge.inria.fr http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

Aug. 12, 2009

Re: [Pharo-project] There are still problem with keyboard shortcuts in Windows

by Mariano Martinez Peck

2009/8/12 <csrabak(a)bol.com.br> > Yes: Windws XP SP3 (32 bit), Pharo beta image last update #10413. With some > corrections on your report below: > Sorry. I didn't understand you. Did you have the same problems as I had? > > > Em 12/08/2009 17:49, *Mariano Martinez Peck < marianopeck(a)gmail.com >*escreveu: > > > Hi: this is broken since a lot of time (not new). It happens only on > Windows I think (in Linux it works ok). > > I have preference duplicateAllControlAndAltKeys enabled. > > Browse: works ok with ctrl + b and alt + b > Implementors: Only works with alt + m . ctrl + m doesnt work. > Senders: works ok with alt + *n* and ctrl + *n* > Inpect: Only works with alt + *i* . ctrl + *i* doesnt work. > Close windows: Only works with alt + w. Ctrl + w is interpreted as > undo (ctrl + z ) > Undo: works ok with ctrl + z and alt + z > Print it: works ok with ctrl + p and alt + p > Do it: works ok with ctrl + d and alt + d > > In summary, there are problems with Implementors, Inspect and Close > windows. At least, the one I tested, but there can be more. > *This happens not only with core but also with dev, both clean image. > > I am waiting someone to confirm this so that to open a bug ticket. > > anyone? > > Thanks > > Mariano > > * > > > _______________________________________________ > Pharo-project mailing list > Pharo-project(a)lists.gforge.inria.fr > http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project >

Aug. 12, 2009

Re: [Pharo-project] There are still problem with keyboard shortcuts in Windows

by csrabak＠bol.com.br

Aug. 12, 2009

Re: [Pharo-project] Extending #< to compare all numbers

by Ken.Dickey

"Schwab,Wilhelm K" <bschwab(a)anest.ufl.edu> > Floating point is not always what it seems. Â Hence my comment that IEEE floats get "the wrong answer fast". I have used interval math, continued fractions, and linear fractional transforms (a.k.a. exact reals). I agree that each representation has its challenges. Let's talk for a second about integers. 0 = (0+0i) --> true 1 = (1+0i) --> true 0 < 1 --> true (0+0i) < (1+0i) --> ?? which answer here gives me the least surprise ?? To put it another way (A = a) --> true (B = b) --> true (A < B) --> true (a < b) --> ?? what do you expect to see here ?? > By extension, I argue that > computer-represented complex numbers are not always what they seem, only > more so. Â Agreements: computers don't do math well. Computers approximate math. We would prefer to get the best approximations possible and be told when we are in deep waters. There are math systems (e.g. using interval arithmetic) which either complain that they can't come up with a sensible answer (all the bits are roundoff error) or go back and recompute with higher precision numeric representations in order to get X digits of correct precision. I am _not_ proposing to make Pharo into such a system. > Intuition resulting from lots of exposure to mathematicians suggests that > they consider this non-trivial but well-known. I don't consider "What Every Computer Scientist Should Know About Floating-Point Arithmetic" trivial -- especially for us non-mathematician users of numbers. [ http://docs.sun.com/source/806-3568/ncg_goldberg.html ] > If I am reading this correctly, defining $< is making a promise we can't > keep, or perhaps we simply should not try. Again, I am using unit tests as a fixed point. I want "if A=a and B=b and A<B then a<b" to work as I expect. I consider anything else to be deeply broken. > If you can find something that claims to produce a sensible ordering of > complex numbers, please post a reference. Â For now, my sense is that such a > thing cannot exist. I posted what I consider a sensible ordering which unit tests the property I care about. It happens to be a total ordering (not that I really care). I can certainly remove Complex>>< from the code, but I deeply dislike breaking basic logic on integers. I would prefer to have something more meaningful than "mathematicians can't agree on a theoretical ordering of complex numbers, so practical logic must fail". Do you really not believe that (0+0i) = 0 ?? Why, such numbers must be imaginary!! ;^) -KenD

Aug. 12, 2009

[Pharo-project] There are still problem with keyboard shortcuts in Windows

by Mariano Martinez Peck

Hi: this is broken since a lot of time (not new). It happens only on Windows I think (in Linux it works ok). I have preference duplicateAllControlAndAltKeys enabled. Browse: works ok with ctrl + b and alt + b Implementors: Only works with alt + m . ctrl + m doesnt work. Senders: works ok with alt + m and ctrl + m Inpect: Only works with alt + m . ctrl + m doesnt work. Close windows: Only works with alt + w. Ctrl + w is interpreted as undo (ctrl + z ) Undo: works ok with ctrl + z and alt + z Print it: works ok with ctrl + p and alt + p Do it: works ok with ctrl + d and alt + d In summary, there are problems with Implementors, Inspect and Close windows. At least, the one I tested, but there can be more. This happens not only with core but also with dev, both clean image. I am waiting someone to confirm this so that to open a bug ticket. anyone? Thanks Mariano

Aug. 12, 2009

Re: [Pharo-project] Complex neurotic

by csrabak＠bol.com.br

Aug. 12, 2009