Mailman 3 March 2006 - Edu-sig

Re: [Edu-sig] Properties use case
by Laura Creighton March 22, 2006

March 22, 2006

In a message of Sat, 18 Mar 2006 14:11:03 EST, Arthur writes: >> >-----Original Message----- >> >From: edu-sig-bounces(a)python.org >> >[mailto:edu-sig-bounces@python.org] On Behalf Of Arthur >> >Sent: Saturday, March 18, 2006 1:39 PM >> >To: 'Scott David Daniels'; edu-sig(a)python.org > >>>I don't understand, really, the distinction >> >between a vector expressed as a list and a vector expressed >> >as a tuple, from the concept of a complex number in mutable >> >form, and one in immutable form. >> > >> >If you feel like trying to help... > > >Put another way, if I take the PyPy implementation of the complex primiti >ve, >and comment out the 2 property lines that restrict the write to real and >imag - and instead of calling it a primitive I call it a class. And I use >the class as such - where have I gone wrong? > >Art I'm confused too. It sounds to me that you want to invent your own type. Does your type have any relationship to the complex numbers that we know and love, or do you just want a type that has 2 parts? In particular, check out: http://home.scarlet.be/~ping1339/complget.htm#Polar-representation Do you want this a + ib = r (cos(t) + i sin(t)) to be true for your type as well? I think so. I'm worried that when you start mutating the type -- as opposed to simply assigning new values to it -- you can create a state where this is _not_ true. Am I wrong? Laura

6 21

Re: [Edu-sig] Properties use case
by Laura Creighton March 21, 2006

March 21, 2006

In a message of Tue, 21 Mar 2006 11:17:42 CST, "Michael Tobis" writes: >I use numeric a lot, and I understand what you mean. > >Perhaps there is some Python-like scientific language yet to be >invented, but on the other hand, perhaps the interface between >convenient latent typing and efficient strong typing may be fated to >always be a bit uncomfortable. PyPy. we are working on it. Type inference engine works now, JIT about to happen .... Dynamic Languages Need Not Be Slow!! (Psyco and now PyPy Slogan) Laura <snipped the x-reference ...>

3 2

Re: [Edu-sig] Properties use case
by Laura Creighton March 21, 2006

March 21, 2006

Arthur, have you tried using Psyco? Then you get to write your code in a naive, straightforward fashion, and then you get something that runs nearly as fast. Plus no headaches from having to write your code inside out, like numeric makes you do, all too often. Laura, sold on it, In a message of Tue, 21 Mar 2006 11:57:16 EST, Arthur writes: > > >> >From: Michael Tobis [mailto:mtobis@gmail.com] >> > >> >Note that when you stray from pure python you shrink your >> >user base and complicate your support issues substantially. >> > > >Haven't had the opportunity to code much anew, but am still replaying to >myself where I am with these issues, and in the context of the discussion >. > >When Kirby mentioned that he was not using Numeric for the purposes of hi >s >pedagogical approach to programming and numerics, I said - right on, why >would you unless it was necessary. More transparency. > >And so realizing that >a) my objectives are most fundamentally pedagogical >b) Numeric is not playing nice with me at the moment >c) I am only using 1% of the capacity of Numeric to do heavyweight array >processing >d) When I look into the code that Numeric needs to use to talk to - say >- >laplack, we begin to approach *my* definition of creepy. >e) """Note that when you stray from pure python you shrink your > user base and complicate your support issues substantially.""" > >For example, numpy's documentation is not free, at the moment. > >I am of course thinking whether I have been knee-jerk in bringing Numeric >into play as a fundamental tool for my application. > >Which I why I then move on to trying to get serious about gaining some >profiling skills. Gain some intelligence about the trade-offs of doing t >he >kind of simple linear algebra my application requires in pure Python, ver >sus >what I may gaining by the creepy calls to laplack. > >Judgment calls need to be made in the end, but I take them seriously enou >gh >to want them to be informed judgment calls. > >No conclusions as yet. > >Art > > > >_______________________________________________ >Edu-sig mailing list >Edu-sig(a)python.org >http://mail.python.org/mailman/listinfo/edu-sig

1 0

Thinking about my class...
by kirby urner March 18, 2006

March 18, 2006

Early AM before school in Portland, and my Brother multifunction printer, soon to be retired (factory remanufactured clone enroute, after we broke the paper feeder), is printing up a storm. We'll be doing a simple substitution cipher, i.e. substitute a random shuffle (permutation) of A-Z and space, for some coherent plaintext (also in Latin-1), to get garbled ciphertext, then reverse. Here's my worksheet (decrypt not included): ==== from random import shuffle from string import uppercase def makefunction(): theletters = list(uppercase[:26] + ' ') copyof = theletters[:] shuffle(copyof) return dict(zip(theletters, copyof)) def encrypt(plaintext, thekey): return ''.join([ thekey[i] for i in plaintext ] ) STEPS: Use File | New Window to start a new program file. Save As "something.py" (in site-packages would be OK). Enter the above code, paying attention to indentation. Save again. REMARKS: We import from modules to get additional features. The file you save is itself a module. You can import your own modules, as well as modules provided by others. [ side 2 of this worksheet is something about xml-rpc -- hitting a Perl utility with a street address, getting back lat/long ] Kirby

2 2

Coding Tool Is a Text Adventure
by Jonah Bossewitch March 16, 2006

March 16, 2006

http://wired.com/news/technology/0,70413-0.html?tw=wn_index_14 just saw this, and thought it might be interesting for this group. /jsb ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Jonah Bossewitch Senior Technical Architect ccnmtl.columbia.edu jonah at ccnmtl dot columbia dot edu 212.854.1815 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1 0

Announcing edupython list
by Anna Ravenscroft March 13, 2006

March 13, 2006

In order to facilitate small groups working on specific Python-in-Education projects, we have launched an edupython list on google groups (http://groups.google.com/group/edupython or edupython(a)googlegroups.com). We envision participation by people trying to coordinate work on the nuts and bolts implementation of a project, with frequent progress reports and requests for suggestions and comments coming back to edu-sig. The list developed as a result of a quite well-attended and enthusiastic BOF meeting at PyCon. This edupython list is not intended to replace edu-sig, which remains very strong for theoretical and philosophical discussions, and for getting input and suggestions from a wider group, but is also necessarily higher bandwidth. We invite anyone working on Python-related education projects to join the list. Cordially, Anna Martelli Ravenscroft

1 0

1 hour introduction to Python
by Grégoire Dooms March 12, 2006

March 12, 2006

Hello, next friday I'll give a one hour hands-on Python introduction to our students in second year of Bsc in Computer Science. The course is part of a "tools class" (other courses in this class are about svn, latex and so on). They already know Java and Oz. The first objective of the course is to arm them with shell scripting tools but I would like to convince them to continue learning/using/loving it for other tasks too. I think I will basically do this (10-15 minutes per item) : - language syntax - read/write files, os.listdir and glob.glob - os.system, os.popen, urllib.urlopen - online documentation and other resources Do you have ideas of subjects/features I could show them ? Or useful resources ? -- Grégoire Dooms

3 2

Entering Squeakland
by kirby urner March 11, 2006

March 11, 2006

So McCarty, my supervisor @ Winterhaven, treasured faculty, talked me through a demo dowload of Squeak to the Toshiba, as kids were settling into their seats (projecter already running). Now I have it open in another tab, within FireFox. Let's go see if the plug-in actually works (didn't quite get to it, as class was starting).... Got a mouse-on-wheels, Loading Project... (I passed on getting updates this time)... OK, Teds Ocean comes up, I beckon my wife, and she comes over to watch. "What about the car?" That's what Tara's been up to, programming a car (one of the eToys exercises). We check another canned example: Stair. Quite fun then, not just an applet as plugin, but I guess the whole Squeak development environment, which is the 6.5 meg I downloaded. The browser simply wraps this deeper think tank with a friendly and familiar out frame, one which conveniently connects me to worlds I'll want to check out anyway. OK, so now that's on the Toshiba. Tara can show us about the car. And I can learn more about this teaching environment (I've been also looking at the books). Kirby

6 12

Getting ready for class...
by kirby urner March 10, 2006

March 10, 2006

Here's what I'm starting with today: http://www.4dsolutions.net/ocn/python/zoo.py Note: inheriting from object at the top level, per André's suggestion. Kirby

3 7

A Quick Puzzle
by kirby urner March 9, 2006

March 9, 2006

Here's a quick puzzle, that'd make a good source of Python programs, or programs in other languages: Assume dogs live at 7 times the rate of a man, such that when a man ages but one year, the dog ages by 7. Now assume a dog is born later than you, and you get her as a puppy (feel free to mess with these gender assumptions). At some point, as long as you keep living (assume that you do), the dog will catch up to you, and overtake you in age (the dog too, keeps living, at least long enough for the two life-lines to intersect). So challenge: write a program where you input the two birth dates, yours and your dog's. What the script returns is the very day of the very month of the very year, on which you and your dog might reasonably celebrate a "same age" intersection, a "birthday in common" if you will (we could get more precise, but only if the birth times are known with equal precision). I'm actually working on this project now, in anticipation of earning five dollars. Jon Bunce, another Wanderer, has already worked out a formula and shared it around. But I'm thinking just for fun, to do something totally brute force using Julian dates. Anyway, it'll be fun to compare different solutions, in terms of accuracy, quirkiness, readability, speed -- lots of interesting criteria. Just another puzzle for the literature, not my invention, just something I've thought about. A guy with a real dog and a real interest in the answer, came to Don Wardwell with it, looking for the services of a real think tank. Over on the Math Forum, I couched it as a puzzle for cgi scripters, i.e. make up a web site calculator around this, using JavaScript or whatever (a new way to do story problems). Of course similar games may be played with other animals with different "life rates." Don't get too hung up on what actual ratios to use, unless that's a stated goal of the lesson. In most cases, just take these as puzzles, like Sudoku, not as literally true biology lessons. Kirby

5 7