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

Re: [Pharo-project] Complex Solutions
by Ken Dickey Aug. 31, 2009

Aug. 31, 2009

Bill, I have already said that I think IEEE floats tend to give the wrong answer fast. Better solutions are hard to come by, however, as they definately depend on the problem domain. E.g. Apple's old plot program used interval arithmetic and did a great job with functions like x * sin(1/x) near zero. You could zoom in time after time and still get an accurate plot -- where IEEE floats are useless. Interval math is also great when you have measurement error and you can't fool yourself about error analysis. It is sure helpful to know the difference between 3.023+/-0.001 and 3.023+/-2e56 . Interval math does have splits and it is sometimes useful to calculate the probability distribution of the value in the interval. No perfect world, sigh. If you are using ideal mathematics, on the other hand, there are exact real representations which can be used, but these are pretty heavy weight for day to day computing. Another day; a little better approximation, -KenD >From: "Schwab,Wilhelm K" <bschwab(a)anest.ufl.edu> ... >As for the zero vector, it is hard to say. Note that a nearly zero vector > is going to have a very poorly defined direction in that the result will > likely be dominated by roundoff error. Often there is a better way to > compute such things; a rearrangment of governing equations can make a world > of difference - that's not something you can fix, it will be > problem-specific how one would avoid computing the argument in tricky > situations. One possible approach is to simply compute the angle the same > way for all values and let under/over flow errors take care of the garbage. > Another would be to raise an error. Finally, you might define #argument, > #argumentIfSmall: (takes a block for the troublesome case) and > #argumentIEEE to use their convetion. > >Something that deserves a careful look is the test for floats being close to > each other. I have been supicious about that for a while, and on first > glance, Dolphin seems to handle it very differently from the way Squeak > does. IMHO, being different from Dolphin is cause for a good think. We > shouls also see how VW handles it. > >Just looking at #closeTo:, it appears to "think" that 10^-4 is a good > threshold, and that is questionable depending on the scales involved, and > is far from the smallest float that can be reasonable represented. > >Bill

1 0

[Pharo-project] How to build a GUI
by Torsten Bergmann Aug. 31, 2009

Aug. 31, 2009

>Now i`m adding new capabilities. That means you are already working on the next milestone ... >but It does not have sense to raise something incorrect or incomplete If that wouldnt make sense you wouldnt have a pharo image (or any other kind of software) in your hands :) Even when you can prove your software is correct (whatever that means in a context of a UI builder compared to an algorithm) there is always something you can add. So it will never be complete. Even when it is not complete in your own eyes you should declare it "pre-alpha" work and make it accessible. Dont fear that others look at your code! Hey with Smalltalk in your hands your code cant be that ugly ;) You already got positive feedback that you started such a project and people are able to help or tell you what features/directions they would like to see. They may even help you to find and fix bugs. It could also be that nothing happens and you work on it alone as it is now. It may also be that you loose interest and others take it as a base and continue with your work (depending on license). Who knows ... >I prefer not to say when I will conclude my work Release early and show a steady progress by releasing often. Thats the key to success. And listen to feedback. Otherwise you will work towards "the perfect time to release" (remember you already said it will be in a releasable state after 14 days) You already mentioned the next tasks on your list (which will continue to grow the more you work since you will get more ideas and it will become more and more work for a single person). Most of the time projects working towards perfection will never be released or used. There is also the problem that others will start developing a similar one meanwhile since they cant wait or dont know that there is already someone investing his time and knowledge. Even when you think the day has come and anything is perfect you may be disappointed since it is possible that people disagree with the result and come up with something different. Even when it is good others may develop different UI builder frameworks (have a look at Java ;) As I said there is no "complete" or "correct" code - the world is spinning day by day and projects, people, contexts, ... will change. Anything that does not change or adapt to the next day can be declared as dead. >IÂ´m put much effort in that work and i want do it good. However ... it is your decision. I for my part would really like to see a nice UI builder for one of the early releases of Pharo, especially since you already put so much effort into it. Bye Torsten -- Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/atbrowser

2 1

[Pharo-project] How to build a GUI
by Torsten Bergmann Aug. 31, 2009

Aug. 31, 2009

>I believe than in two weeks i could up in SqueakSource Any news from the UI builder front? Bye Torsten -- Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/chbrowser

4 3

Re: [Pharo-project] Complex Solutions
by Ken Dickey Aug. 30, 2009

Aug. 30, 2009

>From: "Schwab,Wilhelm K" <bschwab(a)anest.ufl.edu> ... >On #cosH vs. #cosh, etc.,I do not like what you have done, but it's hardly > cause to start a war. I would be more inclined to agree with your no-typo > argument if you spelled out hyperbolic. We write cos and cosh; I see no > advantage to typing cosH, which could just as easily be errant as cosh. I don't understand your comment. "cos" and "cosh" differ in a single, lower case character. In a line of code where I expect to see "cos" but the text is actually "cosh" I would be more likely to misread the text as "cos" than if the text is "cosH". In this case the capital is distinctive. It clues the reader to the difference. [I once had a bug in a Fortran program where 1 was substituted for l (ell) but in the punch card font, it was very difficult to distinguish this]. >#angle vs. #argument. The terminology of modulus and argument is heavily > drilled into engineers and physisists, so I would go with that inertia vs. > anything from Scheme or Lisp. Thanks. I'll make the change. >>Complex>>angle looks like it will answer zero for a value of zero?? >>Complex>>AFAIK, >> there should be no direction for a zero vector. In a way, it is >> splitting hairs because exact comparisons of floats are dubious, but >> it probably should raise an error for zero. I'll raise an error. Zero divide? One again, thanks. -KenD

2 1

[Pharo-project] [ANN] KomHttpServer 7.1.2
by Torsten Bergmann Aug. 30, 2009

Aug. 30, 2009

>In order to install Kom in your image add KomHttpServer's Squeaksource >repository ( http://www.squeaksource.com/KomHttpServer.html ) and load >the following packages: >... Which is easily done in Pharo by evaluating ScriptLoader loadComanche Bye Torsten -- Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/atbrowser

1 0

[Pharo-project] [ANN]10428
by Henrik Johansen Aug. 30, 2009

Aug. 30, 2009

- Issue 1117: environmentAt:put: now returns the added value

1 0

[Pharo-project] [ANN] KomHttpServer 7.1.2
by Giovanni Corriga Aug. 30, 2009

Aug. 30, 2009

Hi all, the latest version of KomHttpServer is now available on Squeaksource. Since the latest release, the following changes have been integrated: - reliably close the connection socket if the Kom process is terminated while debugging (thanks to Julian Fitzell) - fix a bug preventing ModFile from serving static files (thanks to Francois Stephany) - compatibility code to let Kom run in both Pharo and Squeak (thanks to Micheal Rueger and Damien Cassou) The code has been tested in the current development versions of both Pharo and Squeak. In order to install Kom in your image add KomHttpServer's Squeaksource repository ( http://www.squeaksource.com/KomHttpServer.html ) and load the following packages: - DynamicBindings-GiovanniCorriga.10.mcz - KomServices-gc.19.mcz - KomHttpServer-GiovanniCorriga.50.mcz Ciao, Giovanni

1 0

[Pharo-project] Process>>#'environmentAt:put:'
by James Foster Aug. 30, 2009

Aug. 30, 2009

The typical Dictionary protocol is to return the added value rather than self. I suggest that Process>>#'environmentAt:put:' follow the same convention. Dictionary new at: #'James' put: 1. "returns 1" Processor activeProcess environmentAt: #'James' put: 1. "returns aProcess"

3 3

Aug. 30, 2009

- Issue 1089: Pragma >> #analogousCodeTo: fix - Issue 698: InvalidDirectoryError should not implement defaultAction - fixing comment of oldFileNamed:

1 0

Aug. 30, 2009

[ANN] 10426 Issue 1107: Clipboard Problem on Mac build 10424 MacOSClipboard initialize. + UITheme current class beCurrent.

1 0