Mailman 3 June 2000 - Edu-sig

sample PowerPoint presentation
by Kirby Urner 07 Jul '00

07 Jul '00

Greetings educators -- For those of you with PowerPoint and/or the requisite browser plug-ins, I've tossed a slide show on the web at: ftp://ftp.teleport.com/pub/users/pdx4d/images/synergeo.ppt This is my standard 'Beyond Flatland' curriculum, wherein I mix spatial geometry, virtual worlds, computer programming (these days Python), and synergetics. Given this is just an outline of a talk, there's not a lot of discussion (few words). To present this material effectively, you'd need to study the background readings e.g. http://www.inetarena.com/~pdx4d/ocn/cp4e.html (see 'Numeracy + Computer Literacy' series). Feedback welcome. Kirby 4D Solutions PS: the file is approx 625K

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beginner trouble, indexing starting w/"0"
by Matthew J. Moelter 03 Jul '00

03 Jul '00

I have been following the Python edu-sig list for a while and in the spirit of observing a "beginner" I decided to show my dad some Python. (He is a long-ago-retired high school math teacher with virtually no programming experience.) Below is how far our session got before we had "trouble": Python 1.6a2 (#54, May 6 2000, 00:26:29) [CW PPC w/GUSI2 w/THREADS] Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam >>> s='Matthew' >>> print s Matthew >>> s 'Matthew' >>> len(s) 7 >>> s[1] 'a' >>> s[0] 'M' >>> While he understood the idea of indexing fine he didn't understand the first element being indexed with "0". When he taught vectors or matrices to the students they usually indexed from 1 to N (vectors), or 1 to N by 1 to M (matrices). The upper left element in a matrix was A(1,1) or something. If this is truly the way Python is configured it seems to me that this could be an important stumbling block. I do not know enough about Python myself to see if this is a necessary approach or if it can/could be changed. Or could it be changed at the users option? "starting index=1" or something? Matt *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*- Matthew J. Moelter office: (805) 756-2065 Department of Physics email: mmoelter(a)calpoly.edu Calif Polytechnic State Univ fax: (805) 756-2435 San Luis Obispo, CA 93407

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Re: [Edu-sig] beginner trouble, indexing starting w/"0"
by Stephen R. Figgins 30 Jun '00

30 Jun '00

>While he understood the idea of indexing fine he didn't >understand the first element being indexed with "0". >When he taught vectors or matrices to the students they usually >indexed from 1 to N (vectors), or 1 to N by 1 to M (matrices). >The upper left element in a matrix was A(1,1) or something. This is true, but on the other hand, if he were to graph a vector, like say (4,3) he would start the vector from x and y coordinates (0,0). What he ran into is the same problem that every kid runs into when they start drawing the number line, and realize they need to start from 0, not 1. Most programming languages extend that concept to array indeces. It is a stumbling block, but a very small one, and you learn something in the stumble. Not all stumbles are bad ones. Stephen

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Re: socket-module
by A[r]TA 29 Jun '00

29 Jun '00

> The lowest level code is imported at the top by the statement "from > _socket import *". This imports a module written in C. If you have a > Python source distribution, you can find it at Modules/socketmodule.c. I've been looking there, and for the socket.send-option I found this: /* s.send(data [,flags]) method */ static PyObject * BUILD_FUNC_DEF_2(PySocketSock_send,PySocketSockObject *,s, PyObject *,args) { char *buf; int len, n, flags = 0; if (!PyArg_ParseTuple(args, "s#|i", &buf, &len, &flags)) return NULL; Py_BEGIN_ALLOW_THREADS n = send(s->sock_fd, buf, len, flags); Py_END_ALLOW_THREADS if (n < 0) return PySocket_Err(); return PyInt_FromLong((long)n); } static char send_doc[] = "send(data[, flags])\n\ \n\ Send a data string to the socket. For the optional flags\n\ argument, see the Unix manual."; -----------END CUT--------------- A stupid question maybe. I want to find the parts where is described HOW a TCP-packet is created. Something like: -IP from sender -IP from receiver -data Is it possible? A[r]TA -Life can kick your ass, but all you got to do is stand up and move on...

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socket-module
by A[r]TA 27 Jun '00

27 Jun '00

Hi, I'm having a question. Maybe a strange one, but don't blame me. Just a newbie or something like that :-) If you're looking at the source from SOCKET.PY, you see a two classes. One for the socket-object and one for the file-descriptor. But, this module (in Windows) doesn't import anything. And par example: def accept(self): sock, addr = self._sock.accept() return _socketobject(sock), addr This is the accept method. Where can I see the lowest-level-Python-code? I can't see the real code from HOW it's accepting the connection. Is this possible and how? It's basically for me to see the TCP/IP-packages Python is creating....(very low level) A[r]TA -- -Life can kick your ass, but all you got to do is stand up and move on...

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Howto: MacPython and Tkinter
by addyd＠unk.edu 26 Jun '00

26 Jun '00

I see that earlier there was a discussion regarding Mac support for Python and references were made to problems with Tkinter on Macs. I ran across the following reference as to why the problem occurs and how to get around it. If you were already aware of this info when the discussion was held, I apologize. http://schockwellenreiter.editthispage.com/python/tkinterenglish.html Darren Addy Internet Specialist and Interim Web Presence Coordinator Office of Information Technology Services University of Nebraska at Kearney

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Perhaps we need a Python tutorial with this approach...
by addyd＠unk.edu 20 Jun '00

20 Jun '00

Perhaps a writer out there would like to take this approach? >From a review of the book "Who's Afraid of C++?" by Steve Heller: http://slashdot.org/article.pl?sid=00/06/09/2153222&mode=thread In his unique approach, Steve Heller presents programming concepts and information as a conversation between teacher and student. Breaking with traditional lecture-on-paper format, Heller demystifies computers, programming, and C++ for absolute beginners. That's right -- he recruited a full-fledged novice user, capable of little more than e-mail and word processing, and turned her into a decent programmer while reviewing this book. (She became Mrs. Heller shortly after that.) Any computer owner with time, the ability to follow directions, and the willingness to learn could also become a programmer. The resulting text is more of a collaboration, or a commentary. Steve, the author, presents his information and then Susan, the novice, interrupts to ask questions. The big gamble is that her questions are the same that the average reader would ask. It largely pays off, only occasionally belaboring a point. (To be fair, it could also be called 'reinforcing a point.') (more to the review...and reader comments follow at the link given above) Darren Addy Internet Specialist; interim Web Presence Coordinator Information Technology Services University of Nebraska at Kearney

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RE: CP4E and the Python thread (Kirby Urner)
by L. Humbert 16 Jun '00

16 Jun '00

Hi Kirby Urner, hi pythoners, hi teachers, hi developers, after reading the above mentioned mail with the "math through programming" vision, I want to tell you, how to produce nice *.PDF-Files with Python. So you can switch from ppt to PDF. You may take a look at: http://www.reportlab.com/ There you will find tools to create well formed and layouted PDF-Files and a method for doing this with xml-Sources, which is converted to PDF by PythonPoint. I used it with impressive results. L. Humbert

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CP4E and the Python thread
by Kirby Urner 15 Jun '00

15 Jun '00

I've continued to share re my "math through programming" vision (these days Python-centric), on the Math Forum, in many ways the hub website for the math educator community. Here's an example thread: http://mathforum.com/epigone/k12.ed.math/tahwhawar (first post of June 6 is almost verbatim something from here -- fixed a typo -- followed by two additional posts, so far, Brian Harvey's of June 7 and mine of June 12). As some of you know, Python is one of several threads weaving in to my "PowerPoint presentation" (just came back from one of those seminars where all the presenters have laptops and use PowerPoint to help them walk through their talk). Among other items of interest re my school of thought (PowerPoint slide): We... =================== At the Oregon Curriculum Network website we: * Use Polyhedra to introduce OOP[1] * Organize Polyhedra as per the Fuller hieararchy (FH) -- R. Buckminster Fuller being the futurist, and geodesic dome guy)[2] * Use a sphere packing lattice for context (not just XYZ)[3] * Use triangular packing (not just grid of squares) * Develop Pascal's Triangle (PT) as a tandem "hub" for basing math explorations (i.e. PT + FH in sphere packing context) =================== In other words, there's an aesthetic/theme (as in "desktop theme" for you Windows user) which converges with Python for me (Python having its own thematics, e.g. Monty Python plus assorted snakes, and lets not forget personalities). Another slide: =================== CP4E = Numeracy + Computer Literacy Logic: All need to learn some math Some math means some programming (these days) Ergo: All need to learn some programming OCN approach: (just one of a great many feasible): Python + Povray + HTML ... start somewhere, add more tools/skills as you go =================== Another slide: =================== Math content: Fuller's Hierarchy (FH) Volume table Sphere packing context FCC/HCP/BCC/SC (IVM) Jitterbug Transformation Angle/Frequency distinction Principles/Cases distinction Pascal's Triangle (PT) Triangular Numbers Tetrahedral Numbers Fibonacci Numbers Phi Binomial Theorem Pascal's Tetrahedron Prime numbers in... Trinomial Theorem Gaussian distribution (Bell Curves) Probability and Permutations =================== My seminars these last two days weren't anything to do with Python or math ed (directly), had more to do with organ transplants and "cadaverous livers" (there's a connection here to "The Meaning of Life" however, as in: "but I'm _using_ it!").[4] I gave myself permission to go to towards the deep end of the pool in http://mathforum.com/epigone/math.teaching.technology/freldskeldky discussing in my 2nd post how to generalize from simple domain/range lingo to a more overview/big picture perspective, ala NASA-style computer-enabled countdowns (t-minus whatever) to whatever milestones (e.g. liftoff). Then I assure people I'm not trying to crush more spiritual vocabularies by sounding to "techno" all the time (on the contrary, I'm leaving that door wide open) -- a kind of reassurance I'm sure others would rather not see. Only after posting this meditation did I discover Dr. Knuth's lengthy lecture series on God and Computers at MIT, viewable/hearable via the web thanks to Dr. Dobbs Journal.[5] OK, well that works. Knuth has already figured prominently in my posts to this list. He's a "weighty Friend" (as we Quakers say -- nevermind that Knuth is a Lutheran by the sound of it). This helps provide balance/ballast -- I don't want my school of thought to degenerate into purely cult-like aesthetics (remembering what Matthias said about Pythoneers being cultish -- a warning from a sage).[6] Kirby Curriculum writer Oregon Curriculum Network [1] http://www.inetarena.com/~pdx4d/ocn/oop.html [2] http://www.bfi.org/ [3] http://www.teleport.com/~pdx4d/octet.html [4] http://www.montypython.net/sounds/meaning/liver.wav [5] http://www.technetcast.com/tnc_program.html?program_id=50 [6] http://forum.swarthmore.edu/epigone/amte/snuquoiyor (see Feb 1 post)

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Kirby Urner's Sieve of Eratosthenes
by John Posner 08 Jun '00

08 Jun '00

Hi -- I don't know if anyone else has commented on the Sieve of Eratosthenes implementation posted by Kirby Urner at the end of April. I put my response on the back burner until now, so here goes ... In my opinion, Kirby's implementation (see below) works too hard. The critical problem is that it uses an old-fashioned LOOP to do the work instead of using a nifty, Pythonic FILTER. After all, a SIEVE is just a kind of FILTER. ------------------------------------------- my implementation # construct a list of candidate whole numbers, # using command-line argument as upper limit import sys limit = int(sys.argv[1]) nums = range(2, limit) # initialize result list primes = [] # process the candidate list until no numbers remain while len(nums) > 0: # first item on list must be prime -- call it "prm" prm = nums[0] # add prime to result list primes.append(prm) # implement the sieve: filter out multiples of "prm" nums = filter(lambda n: n % prm > 0, nums) # display results print primes ------------------------------------------- NOTE 1: For clarity, I think the long-winded forms of "while" and "lambda" are preferable. That is: while len(nums) > 0: <-- instead of --> while nums: lambda n: n % prm > 0 <-- instead of --> lambda n: n % prm The short forms take advantage of a quirk of Python: the Boolean value TRUE is implemented as non-zero/non-empty. NOTE 2: My implementation is a main program, not a function. Packaging it up as a function (say, "erat") introduces a scoping problem: when you attempt to define the lambda function within the "erat" function, it can't see the "erat" function's local variable "prm". Solution: use a default argument to implement a closure, passing the "erat" function's local variable into the scope of the labmda function (cf. "Programming Python", Mark Lutz, O'Reilly & Associates, p. 746): lambda n: n % prm > 0 ... must be replaced by ... lambda n, p=prm: n % p > 0 This ain't for a first implementation! ------------------------------------------- Kirby's implementation def erastosthenes(n): # a prime number sieve, thanks to Erastosthenes # returns list of primes <= n cutoff = n ** 0.5 # 2nd root of n is cutoff sieve = [0, 0]+[1]*(n-1) # [0 0 1 1 1...] with 1st 1 in position 2 results = [] # empty list, will contain primes when done prime = 2 # initial prime while prime <= cutoff: # done when prime > 2nd root of n j = 2*prime # jump to 2*prime (first multiple) # turn sieve elements corresponding # to multiples of prime from 1 to 0, up to n. while j <= n: sieve[j]=0 j = j + prime # scan for a 1 in sieve beyond highest prime so far prime = prime + sieve[prime+1:].index(1) + 1 # now translate remaining 1s into actual integers i=0 for entry in sieve: # step through all entries... if entry: # if entry is 1 (i.e. true) results.append(i) # add prime to list i=i+1 return results # return list of primes ------------------------------------------- -- John Posner, Editor jjp(a)oreilly.com O'Reilly & Associates 860-663-3147

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