[Edu-sig] Fibonacci Numbers and Phi (again)

[kirby urner]

Yes, I would consider that an improvement, though I might go back to a
generator with:

from math import sqrt

rt5 = sqrt(5)
phi = (1 + rt5)/2

def neat_formula(f0, f1, f2):
    while True:
        yield (f0 + f2 + rt5*f1)/2
        f0, f1, f2 = f1, f2, f1+f2

power_of_phi = phi**(-6)
results = neat_formula(13, -8, 5)  # seed me
for k in range(20):
    print("{0:8.5f} {1:8.5f}".format(power_of_phi, next(results)))
    power_of_phi *= phi

Going back and forth between yours and mine is introducing a small delta,
so if the game were to introduce generators as a genre, I could see doing a
bunch of small deltas like this.

Kirby



On Sat, Nov 23, 2013 at 10:54 AM, Litvin <litvin at skylit.com> wrote:

>  Kirby,
>
> You are right, a little program does help to clarify the statement and the
> formulas involved.  But then, keep it really simple (no classes, no
> generators), so that understanding of the code doesn't get in the way.  For
> example:
>
> from math import sqrt
>
> rt5 = sqrt(5)
> phi = (1 + rt5)/2
>
> def neat_formula(f0, f1, f2):
>     return (f0 + f2 + rt5*f1)/2
>
> power_of_phi = phi**(-6)
> f0, f1, f2 = 13, -8, 5
> for k in range(20):
>     print("{0:8.5f} {1:8.5f}".format(power_of_phi, neat_formula(f0, f1,
> f2)))
>     f0, f1, f2 = f1, f2, f1+f2
>     power_of_phi *= phi
>
> There are many other occasions to bring in more advanced tools.
>
> Gary Litvin
> www.skylit.com
>
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