Squeak-dev August 1998

squeak-dev@lists.squeakfoundation.org

99 participants
188 discussions

Re: What determines what becomes part of the base system?
by Dan Ingalls 27 Aug '98

27 Aug '98

Maurice (and all) - >I am curious what makes the Squeak choose something for inclusion in the >base Squeak System? Just wanted to let you all know that the whole Squeak team is at an offsite meeting, so we're temporarily letting communication lapse. You will have to resolve the #nil contorversy and other hot topics of the week by yourselves ;-) Back on Monday. - Dan

1 0

Re: Computer algebra with Squeak
by Leandro Caniglia 27 Aug '98

27 Aug '98

David. Here in the University of Buenos Aires we have been using Squeak for our mathematical work since version 1.16. Today I begun the third course about Squeak and Mathematic. The results we are obtaining are incredible. Of course we have made algebra (LinearSpaces, LinearTransformations, Matrices, Polynomilas in any number of variables, Algebraic Numbers, FiniteFields, Groebner Basis, SLP representations, Permutations, Groups, Functions, etc) and also Numeric Analysis (Integration, DiferentialEquations, PowerSeries, etc.). Currently we are making our first steps in Physical experiments inside Morphic and, again, the results are terrific. If you are interested, we can share our experiences each other. You are invited to contact us by mail to our MathSqueak list at objetosm(a)dm.uba.ar. Saludos, Leandro ----- "Although it is quite possible to write programs which depend on the byte size, this is an illegal act which will not be tolerated" Donald E. Knuth, The Art of Computer Programming, Vol 1. > > Hello, > > I was working on a project to build a small computer algebra system in >Squeak, and have just updated the package that I made available on the web >at http://cage.rug.ac.be/~stes/squeak.html. > > (I think this would be a good application of Squeak, in mathematics, and >I've also added the URL of my package to the Squeak Swiki server at >http://minnow.cc.gatech.edu/squeak.20) > > There's already some simple things you can do with the package (and more >to come) : > > Create a BigInt instance, > >one := BigInt int:1 1 > > Make a polynomial z+1, > >p := Polynomial scalar:one 1 >t := Term scalar:one symbol:'z'exponent:1 'z' >p insertTerm:t 'z' + 1 > > Square the polynomial, > >q := p square 'z'^2 + 2 'z' + 1 > > Add a term in a different variable (to get a multivariate polynomial) > >t := Term scalar:one symbol:'a' exponent:1 'a' >q insertTerm:t 'z'^2 + 2 'z' + 'a' + 1 >q := q square 'z'^4 + 4 'z'^3 + (2 'a' + 6) 'z'^2 + (4 'a' + 4) 'z' + >'a'^2 + 2 'a' + 1 > > Now convert the polynomial from the recursive representation (where >coefficients are polynomials) to the expanded representations, where the >polynomial is an (expanded) sum of monomials, > >p := q makeExpanded 'z'^4 + 4 'z'^3 + 6 'z'^2 + 4 'z' + 'a'^2 + 2 'a' >'z'^2 + 4 'a' 'z' + 2 'a' + 1 > > The total degree and order of the polynomial, > >p degree 4 >q order 0 > > Get the leading monomial (or term etc.) > >p leadingMonomial 'z'^4 > > Convert back to recursive representation > >p makeRecursive 'z'^4 + 4 'z'^3 + (2 'a' + 6) 'z'^2 + (4 'a' + 4) 'z' + >'a'^2 + 2 'a' + 1 > > > I hope to eventually have a good set of 'building blocks' for algebra in >Squeak, and then you could use Squeak for other computations as well >(group theoretical, for instance). > >David. > >

2 1

Re: Arithmetic (was: Polymorphism without protocol dilution)
by stp＠limbo.create.ucsb.edu 27 Aug '98

27 Aug '98

I'd like to add to this discussion that I *strongly* support the wide use of double dispatching (in lieu of multiple polymorphism in the language) rather than generality or adaptation methods, and that there are many potential uses for it with geometrical objects, other kinds of magnitudes (e.g., pitch, duration, loudness), etc. The trade-off is a relative explosion in the number of methods that must be written, but most of these are 1-liners that can be automatically generated. DD is the only realistic (and safe) way to allow the extension of the range of magnitudes. stp _ Stephen Travis Pope _ Center for Research in Electronic Art Technology (CREATE) _ Dept. of Music, Univ. of California, Santa Barbara (UCSB) _ stp(a)create.ucsb.edu, http://www.create.ucsb.edu/~stp/

1 0

Computer algebra with Squeak
by David Stes 26 Aug '98

26 Aug '98

Hello, I was working on a project to build a small computer algebra system in Squeak, and have just updated the package that I made available on the web at http://cage.rug.ac.be/~stes/squeak.html. (I think this would be a good application of Squeak, in mathematics, and I've also added the URL of my package to the Squeak Swiki server at http://minnow.cc.gatech.edu/squeak.20) There's already some simple things you can do with the package (and more to come) : Create a BigInt instance, one := BigInt int:1 1 Make a polynomial z+1, p := Polynomial scalar:one 1 t := Term scalar:one symbol:'z'exponent:1 'z' p insertTerm:t 'z' + 1 Square the polynomial, q := p square 'z'^2 + 2 'z' + 1 Add a term in a different variable (to get a multivariate polynomial) t := Term scalar:one symbol:'a' exponent:1 'a' q insertTerm:t 'z'^2 + 2 'z' + 'a' + 1 q := q square 'z'^4 + 4 'z'^3 + (2 'a' + 6) 'z'^2 + (4 'a' + 4) 'z' + 'a'^2 + 2 'a' + 1 Now convert the polynomial from the recursive representation (where coefficients are polynomials) to the expanded representations, where the polynomial is an (expanded) sum of monomials, p := q makeExpanded 'z'^4 + 4 'z'^3 + 6 'z'^2 + 4 'z' + 'a'^2 + 2 'a' 'z'^2 + 4 'a' 'z' + 2 'a' + 1 The total degree and order of the polynomial, p degree 4 q order 0 Get the leading monomial (or term etc.) p leadingMonomial 'z'^4 Convert back to recursive representation p makeRecursive 'z'^4 + 4 'z'^3 + (2 'a' + 6) 'z'^2 + (4 'a' + 4) 'z' + 'a'^2 + 2 'a' + 1 I hope to eventually have a good set of 'building blocks' for algebra in Squeak, and then you could use Squeak for other computations as well (group theoretical, for instance). David.

1 0

Arithmetic (was: Polymorphism without protocol dilution)
by m3rabb＠stono.com 26 Aug '98

26 Aug '98

At 10:34 AM 8/26/98, Travis Griggs wrote: >Yup. One might call what Squeak has a form of double-coercion. The >generality scale >is built right into the various #adaptToType: messages. So that negates >the use of >the older coercion scheme found as fallback in VW. It also limits having to >reproduce the tree for each of the basic four arithmetic ops (+, -, /, *). >OTOH, it >requires extra message sends to get some work done, and can create intermediate >objects. So beyond needing to create less methods in total, what if any is the real advantage over DD? > >Yes, I still use the DD changeSet. Note that Stephen Travis Pope found a >bug or two >in the LargeInteger stuff, which he generously posted to the archive. I was planning to use DD for the Rectangle arithmetic as well. When I am done how about we unify this with STP's bug fixes? >I haven't done >any actual real work as of late, just poked around. I can't even figure out >where to download the 2.1 stuff for the Mac. The UIUC link downloads a 2.0 >binhex file. I got my 2.1 in st.cs.uiuc.edu Smalltalk/Squeak/2.0/Squeak2.1sea.bin. I seem to remember that after downloading the archive I was surprised because it was name 2.0. Ignore this because inside it is actually 2.1. --Maurice --------------------------------------------------------------------------- Maurice Rabb 773.281.6003 Stono Technologies, LLC Chicago, USA

5 5

Re: What determines what becomes part of the base system?
by JArchibald＠aol.com 26 Aug '98

26 Aug '98

In a message dated 8/26/98 11:56:06 AM Eastern Daylight Time, arning(a)charm.net writes: > I find myself torn between wanting some of these things around (at least > sometimes) and wanting to keep Squeak simple and accessible. I don't have a > good idea on how to draw the line other than to err on the side of simplicity Why does all the good stuff have to be in the image? Can't we get a Goodies collection together as fileIn's (or whatever), with the packages indicating their dependencies on other Goodies (as well as the base system required)? Jerry.

3 2

Re: Block returns out of scope?
by m3rabb＠stono.com 26 Aug '98

26 Aug '98

>It only works because the compiler adds 'aClass' to the method's list of >temps when it discovers it in the block, and then doesn't rescind its scope >correctly and the doens't take notice of it later. I did some hacking to >make block temps work a while ago that 'fixed' this, I'll try to remember >to extract the relevant bits tomorrow. > >What should be written there is >.......setClass:[:aClass| theClass := aClass]. >and 'the Class' would need be a proper method temp. > >tim Tim-- Thanks for clearing this up. My understanding of scoping is no longer swinging in the breeze. I guess this is part of the whole closures inconsistency. --Maurice --------------------------------------------------------------------------- Maurice Rabb 773.281.6003 Stono Technologies, LLC Chicago, USA

2 1

Re: 0-1-Many Pattern
by Hans-Martin Mosner 26 Aug '98

26 Aug '98

One easily overlooked problem with the 0-1-many pattern is that Strings are Collections. So if you have a String, does it mean one string or many characters? VisualWorks has solved this problem in the dependency mechanism by implementing #asDependentsCollection, #asDependentsDo:, #asDependentsWith: and #asDependentsWithout: (if I remember correctly; it's been quite some time since I looked at this). These work with nil (for no element), instances of DependentsCollection (for many) and anything else (for one). I would like to see something like this but abstracted from the concrete problem (dependency). The 'elements' naming convention would suit me fine. Hans-Martin

1 0

Re: What determines what becomes part of the base system?
by Bob Arning 26 Aug '98

26 Aug '98

On Wed, 26 Aug 1998 02:01:24 -0500 m3rabb(a)stono.com (Maurice Rabb) wrote: >I am curious what makes the Squeak choose something for inclusion in the >base Squeak System? Maurice, You raise some good questions. I think that, in part, we are victims of one of the things that makes Smalltalk so appealing to us - that we, individually, can add/modify/delete any part of the system we want. This makes it less imperative for some central authority to make changes deemed necessary/useful by some/all of the community. As to specifics, I find myself torn between wanting some of these things around (at least sometimes) and wanting to keep Squeak simple and accessible. I don't have a good idea on how to draw the line other than to err on the side of simplicity. Cheers, Bob

2 1

Re: Polymorphism without protocol dilution
by Travis Griggs 26 Aug '98

26 Aug '98

Maurice Rabb wrote: > >Scary to have your own quotes, long forgotten, dredged up out of the dust. > >I feel > >like Bill (Gates or Clinton, take your pick). What continues to gnaw at > >brain is > >what you sum up so well with the statement > > > > I regret my inapropriate relationship with my Squeak archives. :-) > Seriously, I didn't mean to use your quote as a kidney punch. I just > though your comments were so apropos. The tough questions are definitely > cyclical. Unfortunately, the lousy ones (ala C++ vs Smalltalk) repeat as > well. > > >For a while now, we've had a ?framework? in VisualWorks that I've thought about > >porting over to Squeak and releasing, but I've always feared the flame about > >diluting protocols. But tonight, I'm coming out. :) > > [munch] > > >blow my friends and teachers away. I would just whip up little expressions: > > > >#((1 2 3 4 5) + #(6 7 8 9 10) * 4) sum > > > > Hmmm, that looks pretty cool and compelling to me. > > >Maybe the arithmetic protocol is one that dilutes better. > > This reminds me of the "is Point a Magnitude or not" discussion. > > Your comments have given me the courage to add the arithmetic protocols I > really want to Rectangle. BTW, is Squeak arithmetic now using some sort of > hybrid between double dispatch and coercion? What is the advantage? It > used to use straight coercion, right? Travis are you still using your DD > changeSet? Yup. One might call what Squeak has a form of double-coercion. The generality scale is built right into the various #adaptToType: messages. So that negates the use of the older coercion scheme found as fallback in VW. It also limits having to reproduce the tree for each of the basic four arithmetic ops (+, -, /, *). OTOH, it requires extra message sends to get some work done, and can create intermediate objects. Yes, I still use the DD changeSet. Note that Stephen Travis Pope found a bug or two in the LargeInteger stuff, which he generously posted to the archive. I haven't done any actual real work as of late, just poked around. I can't even figure out where to download the 2.1 stuff for the Mac. The UIUC link downloads a 2.0 binhex file. -- Travis Griggs Key Technology tgriggs(a)keyww.com Smalltalk - 100% Pure Objects, Always had 'em, Always will!

1 0

← Newer
1
2
3
4
5
6
7
...
19
Older →

Jump to page: