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Topic: When math makes sense - w/ cooking, consruction
Replies: 84   Last Post: Jun 14, 2013 12:33 AM

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 kirby urner Posts: 3,690 Registered: 11/29/05
Re: When math makes sense - w/ cooking, consruction
Posted: May 18, 2013 1:15 PM

> Sometimes I call what I teach "Gnu Math", a pun on
> "New Math" and an
> accurate reflection of what we owe the GNU project,
> in liberating us from
> the high costs of intellectual property owners who
> planned to squeeze it
> out of us until the cows came home. Now we have
> power tools galore, and
> have started work on tractors:
>
> http://www.ted.com/talks/marcin_jakubowski.html
>
> Kirby

Here is a direct quote from something I'm writing back to
a student, in this "correspondence school" I teach at
(DETC is the certifying body, once the State license is
obtained -- we're a startup and still navigating these
waters).

I'm not revealing anything that will give an "artificial
boost" to other students i.e. if they find this first
regarding Python4, Project 1, so much the better.

I claim real insights into abstract algebra are possible
in this project, a manifestation of my confidence about
this "Gnu bridge" twixt STEM math and STEM engineering.

We're not just using graphing calculators anymore in
Kansas, provided Dorothy is lucky enough to get "girl
scout math" in her corner (I use "gsm" as an abbreviation
for the kind of community service DIY based computational
thinking the scouting community is more known for, what
with geocaching and the like).

Kirby
===

You have seen how basic calculator operations + * - / are mapped to
special name methods __add__ __mul__ __sub__ __truediv__. The
same is true for ** (powering): it maps to __pow__.

The first two tests, of reverser * reverser and squarer * squarer are
easily modified to become tests of reverser ** 2 and squarer ** 2
respectively.

def test_inverse(self):
reverser = Composable(reverse)
nulltran = reverser ** 2
for s in "", "a", "0123456789", "abcdefghijklmnopqrstuvwxyz":
self.assertEquals(nulltran(s), s)

def test_square(self):
squarer = Composable(square)
po4 = squarer ** 2
for v, r in ((1, 1), (2, 16), (3, 81)):
self.assertEqual(po4(v), r)

As to the guts of your method, I am optimistic about it passing
these tests. Some additional assertRaises might be nice. Note it's
a ValueError, not a TypeError, that a negative integer exponent
should raise (in the world of multiplication == composition, f**-1
is taken to be an "inverse function" but w're not trying to dive that
deeply into abstract algebra here).

Date Subject Author
5/4/13 Jerry P. Becker
5/4/13 Wayne Bishop
5/7/13 kirby urner
5/8/13 Greg Goodknight
5/9/13 kirby urner
5/9/13 Greg Goodknight
5/9/13 kirby urner
5/9/13 Greg Goodknight
5/9/13 kirby urner
5/9/13 Greg Goodknight
5/10/13 kirby urner
5/10/13 Greg Goodknight
5/11/13 kirby urner
5/9/13 kirby urner
5/12/13 Wayne Bishop
5/18/13 kirby urner
5/18/13 Anna Roys
5/19/13 kirby urner
5/20/13 Robert Hansen
5/22/13 kirby urner
5/24/13 Richard Strausz
5/24/13 kirby urner
5/24/13 Wayne Bishop
5/25/13 Robert Hansen
5/25/13 Anna Roys
5/27/13 Robert Hansen
5/27/13 kirby urner
5/25/13 kirby urner
5/27/13 Richard Strausz
5/27/13 Robert Hansen
5/27/13 Louis Talman
5/27/13 Robert Hansen
5/27/13 Wayne Bishop
5/28/13 Louis Talman
5/28/13 Louis Talman
5/29/13 Wayne Bishop
5/30/13 Robert Hansen
5/31/13 Wayne Bishop
5/30/13 Louis Talman
5/29/13 Robert Hansen
5/30/13 Louis Talman
5/30/13 Robert Hansen
5/30/13 kirby urner
5/31/13 Robert Hansen
5/31/13 kirby urner
5/31/13 Anna Roys
6/2/13 Robert Hansen
6/3/13 kirby urner
6/3/13 Robert Hansen
6/3/13 kirby urner
6/3/13 Robert Hansen
6/3/13 kirby urner
6/3/13 Robert Hansen
6/3/13 kirby urner
6/4/13 Robert Hansen
6/4/13 kirby urner
6/4/13 Robert Hansen
6/3/13 Robert Hansen
5/27/13 Richard Strausz
5/27/13 Robert Hansen
5/27/13 Richard Strausz
5/28/13 kirby urner
5/29/13 Wayne Bishop
5/29/13 kirby urner
5/29/13 Richard Strausz
5/29/13 Robert Hansen
5/30/13 Wayne Bishop
6/8/13 GS Chandy
6/9/13 GS Chandy
6/9/13 Robert Hansen
6/10/13 GS Chandy
6/10/13 Robert Hansen
6/10/13 kirby urner
6/10/13 Robert Hansen
6/10/13 kirby urner
6/10/13 Robert Hansen
6/10/13 kirby urner
6/10/13 Robert Hansen
6/11/13 kirby urner
6/10/13 Robert Hansen
6/10/13 Louis Talman
6/12/13 GS Chandy
6/12/13 Robert Hansen
6/13/13 GS Chandy
6/14/13 GS Chandy