Mailman 3 April 2001 - Edu-sig

Re: [Edu-sig] Algebra + Python
by Brent Burley 02 May '01

02 May '01

Kirby wrote: > There may be a better way to write the factory function than > I've shown below. I'd like to see other solutions: > > >>> def makepoly(A,B,C): > """ > Build a polynomial function from coefficients > """ > return eval("lambda x: %s*x**2 + %s*x + %s" % (A,B,C)) How about this? class poly: def __init__(self, A, B, C): self.A, self.B, self.C = A, B, C def __call__(self, x): return self.A * x**2 + self.B * x + self.C >>> f = poly(2,3,4) >>> f(10) 234 Having to know about classes pushes you more into learning Python as a programming language rather than just using Python as a math exploration tool, but that could be a good thing. You could even expand on the idea by adding additional methods that relate to polynomials (deriv, integral, roots, etc.): class poly: ... def deriv(self, x): return 2*self.A*x + self.B >>> f.deriv(2) 11 Brent

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Observations from the Northwest Science Expo
by Thomas O'Connor 28 Apr '01

28 Apr '01

On March 12 of this year, I participate as a middle school judge for the Northwest Science Expo held on the campus of Portland State University, in Portland Oregon. I was assigned to the team evaluating middle school behavioral science projects along with 8 other scientists and engineers. We evaluated 21 student projects. This was a great group of kids and I want to be clear that this is in no way a criticism of any of their work. I believe that the judges took much effort to value and encourage the students. But as is often the case, a world view can be shattered by an example of something outstanding, which then shows all else to be mediocre. I had one of those experiences at NWSE, and it relates to the use of computers in education. I'd be interested in any comments anyone in this group has to offer. The outstanding example in this case was a project put together by young lady in the fourth grade (who was, by the way competing against 6-8th graders). Her project investigated the effects of varying light/dark cycle periods on bean plant growth. Her experimental design and investigation was reasonably thorough, particularly for someone her age, but not outstanding by comparison to those she was competing with. What struck me as outstanding however, was how she related to her data. When I asked what conclusions she drew from her experiment, she made an expansive hand motion, one of those "it should be clearly obvious to the most casual observer," gestures towards her hand drawn data plots. With wide eyed excitement, she explained how her data clearly proved her original thesis incorrect. It was clear that she had fully internalized her data. In this, she stood apart from here peers. By contrast, most other student I spoke with related to their graphs and charts as fuzzy abstract representations of their data. Some examples: * More than half of the students produced three-dimensional bar charts to display data. Unfortunately, only one student was able to accurately read their bar charts. The others failed to account for the parallax between the bar and the back of the graph which represented the X scale. * One young man was analyzing the effect of color on mood. But when he reported his results, his graph was color coded for color. In other words, his red bar represented the color black, the pink bar represented yellow, the yellow bar represented green. When asked about this, he said his software wouldn't let him pick the colors of the bars in his bar-chart. * An 8th grader noted that her results did not vary significantly from what would have been predicted from a purely random sampling. This was a very enlightened analysis, and the judges all gave her credit for attempting to utilize good statistical analysis. But the statistical theory she was attempting to utilize was clearly well beyond her knowledge and skill level. When asked why so much of her her project display was focused on the statistical analysis of her data when she admitted that she didn't really understand it, she stated, "well, Excel did all the math for me." * A sixth grader did a project to determine which parent the gene for red hair was inherited from. Her knowledge of genetics was impressive, particularly for her age. But the computer generated graphs she displayed conveyed no meaning to any of the judges. Had she displayed and focused on the genealogy charts she had stashed in the back of her project notebook, she probably would have won an award. * There were two students who had a very good project on luminescent solutions and the effects of solution temperature on luminescence. While their presentation was very good, what I found most notable in speaking with them was the rate of change graph they had scribbled on the back of a piece of yellow legal pad to explain the cascade effect they had observed. Their scribbled graph conveyed more meaning than all their beautiful computer generated charts. Questions to ponder: -------------------- * Does the use of the computer to generate charts enhance the synthesis of data, or might it actually hinder it? In this case, the fourth grader who was determining environmental effects on plant growth collected her data by drawing points on her graph each day during the experiment. At the science fair, she was able to articulate the meaning of that data better than other middle school students I spoke with. The only other students who showed equivalent understanding did so by utilizing a scribbled graph drawn on the back of a legal pad. So is there a correlation between the manual plotting of data and the cognitive interpretation of that data? * Gerald E. Jones in "How to LIE with CHARTS," on the "old fassion" approach to charting mused: Having such crude tools might have forced those early chart-makers into slower thought processes. It is conceivable that they actually pondered carefully composition--maybe even the content!--of those pathetically simple charts and graphs. Can it be that in their technological poverty they achieved a higher level of consciousness? Did they actually come to grasp the meaning of their graphic creations? [1] With the proliferation of three-dimensional bar that even the creators can not accurately read, is the real meaning of the data being masked by the visual presentation? * I know from experience that I can take someone who is generally computer phobic but who has a good understanding of statistics, sit them down in front of Excel, and within a few hours they can be using it productively. On the other hand, as I observed, an 8th grader who knows Excel inside and out, cannot do meaningful statistics. So why do so many people insist that schools teach Excel, or Word, or Powerpoint for example? Shouldn't the real focus be on teaching number theory, problem solving, language composition and cognitive perception? I'm beginning to wonder how much benefit computers actually add to the learning process? I'd welcome a discussion on the topic by those who are effectively utilizing computers in their curriculum today. Thanks for the bandwidth. Tom O. ----- Thomas O'Connor toconnor(a)vcd.hp.com Hewlett Packard, Vancouver Washington Phone: (360) 212-5031 Telnet: 212-5031 [1] "How to LIE with CHARTS," Gerald E. Jones, Sybex, 1995, p. XVII. See also: "The Visual Display of Quantative Information," Edward Tufte, Graphics Press, 1983 ----- Thomas O'Connor toconnor(a)vcd.hp.com Hewlett Packard, Vancouver Washington Phone: (360) 212-5031 Telnet: 212-5031

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Algebra + Python
by Kirby Urner 28 Apr '01

28 Apr '01

I like to imagine a fictional but possible world in which computer programming for everybody (CP4E) means smoother integration of math and computer science in the lower grades. In the real world, there's a push to make the teaching of algebra more widespread at the 8th grade level. What I imagine is that this is the grade level where we might formally begin using some programming language (e.g. Python, Scheme) in the classroom -- in the sense of having students look at and write source code. In 7th grade, they might watch the teacher project some command line stuff, but getting under the hood wouldn't happen quite as much. A link between programming and algebra is in this concept of variables. A polynomial in the 2nd degree is typically written as Ax^2 + Bx + C, which in Python is more like A*x**2 + B*x + C. The capital letters are called constant coefficients and they "fix" a polynomial, give it its characteristic "call letters" (like in radio: the is KQPD...). Then x is what varies -- you might stipulate over some domain, e.g. from in [-10,10] (square brackets means inclusive). At the command line, 8th graders would have one kind of function called a "polynomial factory" that turned out polynomials with a specific set of coefficients. These would then be floated as functions in their own right, ready to take in x domain values and spit out f(x) range values. There may be a better way to write the factory function than I've shown below. I'd like to see other solutions: >>> def makepoly(A,B,C): """ Build a polynomial function from coefficients """ return eval("lambda x: %s*x**2 + %s*x + %s" % (A,B,C)) >>> f = makepoly(2,3,4) # pass coefficients as arguments >>> f(10) # f is now a function of x 234 >>> 2*10**2 + 3*10 + 4 # check 234 >>> f(-10) 174 >>> [f(x) for x in range(-10,11)] # remember, 2nd arg is non-inclusive [174, 139, 108, 81, 58, 39, 24, 13, 6, 3, 4, 9, 18, 31, 48, 69, 94, 123, 156, 193, 234] >>> g = makepoly(1,-2,-7) # make a new polynomial >>> g(5) 8 >>> g(f(5)) # composition of functions 4616 >>> f(g(5)) # f(g(x)) is not equal to g(f(x)) 156 The same technique might be applied to a sinewave function. Here the coefficients may appear is follows: f(x) = A sin(Bx + C) + D You can imagine doing the factory function, based on the above example, or using some (better?) strategy. Below is a web resource that implements some of these same ideas, also using a computer language, but to my eye it all looks less intuitive in the J language (what the text says is featured). Is it just me? Is this just because I've spent more time with Python? I'm sure that's partly it. http://www.jsoftware.com/pubs/mftl/mftl.htm Moving beyond 8th grade, we want students to understand what's meant be D(f(x)) at point x, i.e. dy/dx at x -- the derivative. Again, Python makes this easy in that we can write a generic derivative taker: >>> def deriv(f,x): """ Return approximate value of dy/dx at f(x) """ h = .0001 return (f(x+h)-f(x))/h >>> deriv(f,2) # f(x) = 2*x**2 + 3*x + 4 11.000200000026439 >>> deriv(g,2) # g(x) = x**2 - 2*x - 7 2.0001000000036129 If you remember how to take the derivative of a polynomial, you'll know that f'(x) = 4*x + 3 and g'(x) = 2*x - 2 -- so these are pretty good approximations. Somebody challenged us on math-teach to think of how we might teach crypto and number theory to 7th graders. My suggestions are in this thread (Number Theory question, reply to Wayne Bishop, 25 Apr 2001 http://www.mathforum.com/epigone/math-teach/zilbangkan ). I use the IDLE CLI quite a bit, along with my ciphers.py Another post re Python + Intro Calculus, as per the above is at: http://www.mathforum.com/epigone/math-learn/wonbloryeh I think any of us who know some Python, and some math, can write this kind of stuff. It's not esoteric. I'd just like to see more of it, is all, coming from a lot of different corners. That's because I think a CP4E world would have some major advantages over the current one, including more students motivated to comprehend technology at deeper levels (I think adding more computer stuff to math will make it less of a turn off for many students, if done in a cool and interesting way (which doesn't have to mean super glitzy at every turn -- a bare bones CLI ala IDLE can be part of it)). Kirby

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And now for something completely different...
by Arthur_Siegel＠rsmi.com 19 Apr '01

19 Apr '01

Kirby writes - >With a little spit and polish ("search and replace" >in the Povray editor), simple cartoony renderings may be transformed >into more expensive-looking sculptures, as here: > http://www.inetarena.com/~pdx4d/ocn/concavedodeca.html yum. >This gets us into the realm of "math + art" -- always a fertile >realm (good book: 'Connections: The Geometric Bridge Between >Art and Science' by Jay Kappraff -- which is just coming out in >a 2nd edition this month, April 2001). The subject i've been rooting about in for the last few years - projective geometry - a mathmatical discipline that it seems to me was the essential step toward non-Euclidian geometry/Relativity, etc - was itself a direct outgrowth of the purely artistic concerns of Renaissance painters related to perspective. Jason writes - >>Searching on Google for 'lg3d' I come across some nice sites: >>http://www.jps.net/tau/rodpack/rptroctm.htm Surprised Kirby didn't mention it - maybe did not consider it relevant to this list. But Jason you might be interested that the tool that did the actual rendering at this site - Struck - is a java project that Kirby has been close to for some time and originally turned me on to - that evolved into Fluidiom, and which is continuing to evolve in interesting directions. http://www.fluidiom.com/ Unfortunately for me, the list that follows Fluidiom developments tends to communicate in Buck Fullerisms - so I don't keep up very well. But its an interesting place to lurk, nonetheless. ART

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And now for something completely different...
by Kirby Urner 19 Apr '01

19 Apr '01

Speaking of "math through programming", just wanted to share some of my latest results from exploring Python + LiveGraphics3D and Python + Povray. LiveGraphics3D is a Java applet by Martin Kraus, free for non- commercial purposes, that takes Mathematica graphics files (.m extension) and presents them in a web-interactive context, complete with mouse-controlled zoom, rotate, and a stereo viewing option (you have to cross or splay your eyes to see the stereo -- a learned skill). I've taught my polyhedra to display themselves in .m format, via a lg3d.py module, so now I can provide browsers with interactive views such as found at: http://www.inetarena.com/~pdx4d/ocn/lvmviews.html For a long time, I've been using the Python + Povray synergy to generate colorful polyhedra, mostly in wireframe. But one should remember that Povray is a sophisticated rendering engine with a lot more to it. With a little spit and polish ("search and replace" in the Povray editor), simple cartoony renderings may be transformed into more expensive-looking sculptures, as here: http://www.inetarena.com/~pdx4d/ocn/concavedodeca.html This gets us into the realm of "math + art" -- always a fertile realm (good book: 'Connections: The Geometric Bridge Between Art and Science' by Jay Kappraff -- which is just coming out in a 2nd edition this month, April 2001). Kirby

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UNext
by Jason Cunliffe 19 Apr '01

19 Apr '01

http://www.elearningpost.com/elthemes/norman.asp comments? - Jason ___________________________________________________________ Jason CUNLIFFE = NOMADICS['Interactive Art and Technology']

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movables
by Donald 19 Apr '01

19 Apr '01

Hi. I'm currently in a high school computer science class and have been assigned the job of finding a way to move a box, or paddle, for a pong game another student is making. I've tried writing a couple programs, one using a box, another using a circle, neither working. If anyone could help me out, it would be much appreciated. Donald __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/

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PyGame ?
by Jason Cunliffe 18 Apr '01

18 Apr '01

Hi Wondering if anyone here has looked the latest PyGame? http://pygame.seul.org/ Looks like there is some very useful stuff in there - for example CDROM + Joystick drivers etc.. Could be useful for improving installations, tutorials, inteface Joystick to 3D graphics/Math functions, Lightflow, motivational progamming.. lots of blit functions for animation.. for teaching progamming using game context of analyis and design... The recent thread on CS now and in the good old days when computers were driven by rubber bands, reminds me that the prespetn metaphors of widgets and wodgets adn dominance of unimaginative, insanely complex GUIs and operting systems has tended to obsccure some of teh basic things about using computers. For example - when you look ata screen you are looking at a display. How does it get there? How do you change it etc.? I dont mean one shoull take the vacuum cleaner apart everytime you want tidy the house, but at least once in once life, preferably at an early age, take it apart and put it back together. Pygame seems interesting in that you can jump in making stuff and thinkning about logic or gameplay, but also can poke around lower level, deal with interfaces to physical and virtual devices.. some kids really enjoy that. PyGame is thoroughly cross-platform because it is based on SDL http://www.libsdl.org/ <quote> Simple DirectMedia Layer is a cross-platform multimedia library designed to provide fast access to the graphics framebuffer and audio device. It is used by MPEG playback software, emulators, and many popular games, including the award winning Linux port of "Civilization: Call To Power." Simple DirectMedia Layer supports Linux, Win32, BeOS, MacOS, Solaris, IRIX, and FreeBSD. SDL is written in C, but works with C++ natively, and has bindings to several other languages, including Ada, Eiffel, ML, Perl, and Python. [also jokes: A little girl had just finished her first week of school. "I'm wasting my time," she said to her mother. "I can't read, I can't write - and they won't let me talk!" ] </quote> Personally I have never been a game player, so I don't know about all this. They always bored me. Longest ever was couple of days with Sim City, and last summer for a day 'The Sims' with my niece, but I was fascinated by the idea of Sim City and what kind of stuff one could develop beyond it. My idea of computer games was alsways graphic software, music, Forth/Lingo/Python/Zope/Flash programming, etc.. First thing I ever did on my Amiga was bootup a version of Conways game of Life. Then went on to exploring realtime granular synthesis using RGS, and other magical soudn and graphic software written by a brilliant friend. You can read about them at http://www.echonyc.com/~jhhl/software.html I did not sleep much that first week I remember -- hooked me on computers.and wanting to learn how to program. My Amiga background tells me cross-platform multimedia library + Python abatraction interface is a GOOD thing. What's you opinion? - Jason ___________________________________________________________ Jason CUNLIFFE = NOMADICS['Interactive Art and Technology']

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Re: Edu-sig digest, Vol 1 #274 - 1 msg
by L. Humbert 16 Apr '01

16 Apr '01

Hi, in the actual issue vol 24, no.2 (april 2001) of "informatik spektrum" - the german journal for professional informatics (springer verlag) you'll find an article entitled: "Quo vadis, informatik" written by Britta Schinzel and Karin Kleinn pp 91-97 There is a small abstract in english included, which I'll post here. The questions are available in german at the end of the article. On interst you may ask the article authors ( schinzel at modell.iig.uni-freiburg.de ) for translation of the questions into english (;- abstract ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Within a project "Professionalisation of Infor- matics" performed at the Institute for Computer Science and Social Research of the University of Freiburg we want to explore which are the actual standards of professionality in German Informatics, which ways the subject is following at the time, and what is considered as most likely future develop- ment.We want to find out which are the different streams of self definition and leading visions within Informatics, especially with respect to software de- velopment, and how these are participating in the development of Informatics as science and as a pro- fession. We want to invite all colleagues interested in the future of Informatics, in particular also the female ones, to tell us their opinions. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Ludger Humbert http://in.hagen.de/~humbert/

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Re: College CS courses
by Matthias Felleisen 16 Apr '01

16 Apr '01

> From: "Alan Gauld" <agauld(a)crosswinds.net> > Date: Sun, 15 Apr 2001 18:45:19 +0500 > > I guess thats where I see a movement in CS. It used to be > about much more: about the ability to compute with a > machine. It included the operation and networking of > computing hosts as well as the construction of software. > It was also concerned about novel ways to compute - for > example large parallel arrays - nobody seems to teach > these anymore and yet in industry they are more widely > used than ever, but with an ever decreasing number of > grads who know even what they are, far less how to use > them... Correct. CS should, and does, teach automata, logic, type theory, and other stuff. Most grads, and most industry people, preach that this is useless until they realize that something like JAVA is a snapshot of the state of CS from 1985 (According to Gosling). > Now I don't expect colleges to simulate that with > 27,000 files but the principles could be tought, > illustrated and even demonstrated surely? How many > grads today even know how to write a makefile that > could distribute a build? Yeap. Rice's Zwanepoel was one of the very first in the mid 80s to turn make files into distributed, optimistically parallelizing tools. I teach stress testing, but I admit that I don't stress test building a program. We build our programs and docs over night on large servers. > I think many CS departments have lost sight of the > fact that industrial computing requires more than > a kind of super PC user/hobbyist. YES! > > One reason I wrote my online tutor and book was > that too many of the summer break grads we get > think that they can only programme in language > X, I was trying to show that programming is > pretty much the same in any language (especially > if they are imperative in style). Wrong. Consider JAVA and an implementation that uses a copy gc. You're much better off using functional patterns than old-style imperative "this works in any programming language" style "programming." (Sorry I can only put quotes around this word .. I don't consider it programming when someone can form a phrase in Python or Scheme or Java and the phrase "accomplishes" something. "But it works" is the biggest lie in computing.) Unless you learn to program functionally, you will never understand how to build such programs. -- Matthias

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