Re: [Visualpython-users] Beta test version of VPython for Python 3.1 for Windows

[Guy K. K. <g....@ma...>]

Thanks a lot. This code looks *much* more Pythonic already.

On Thu, 16 Sep 2010 06:59:14 Bruce Sherwood wrote:
> Here's another successful test. I replaced the import statements at
> the start of the example program gas.py with the following import
> statements, and deleted the old Numeric code in a try structure:
> 
> from visual.cvisual import (vector, mag, mag2, norm, dot, cross, rotate,
>                        comp, proj, diff_angle, rate, waitclose)
> from visual.primitives import (arrow, cylinder, cone, sphere, box, ring,
> label, frame, pyramid, ellipsoid, curve,
> faces, convex, helix,
>                                points, text, distant_light, local_light)

Another possibility would be to just say

from visual import primitives

And then in the code you could create e. g. a cone using primitives.cone.

Much cleaner than trying to pull in *all* the individual objects into the 
local name space.

> from visual.ui import display
> import visual.crayola as color
> import visual.materials as materials

Do one like this here:

from visual import materials

> import visual.site_settings
> import atexit as _atexit
> _atexit.register(waitclose)
> from math import pi, sin, cos, exp
> from numpy import (sqrt, array, newaxis, add, less_equal, identity,
>                    sort, nonzero, greater_equal, arange)
> from visual.graph import (gdisplay, gcurve, ghistogram)
> from random import random
> 
> This could have been more selective, since gas.py uses only a few of
> the vector and primitive features. Also, gas.py already has a scene =
> display(....) statement.
> 
> A subtle point that one should be aware of: In visual's __init__.py
> there is some complex machinery to deal with the fact that when, for
> example, you're taking the square root of a scalar you want to use the
> math module's sqrt, because it is much faster than using numpy's sqrt.
> On the other hand, you need to use numpy's sqrt if you're taking the
> square roots of all the elements of a numpy array. For functions such
> as sqrt you would want to do something like this:
> 
> from math import sqrt as msqrt
> from numpy import sqrt as nsqrt

Then why "rename" these things? Just import math and numpy directly and use 
numpy.sqrt() or math.sqrt()

This is *much* more clear ("explicit is better than implicit"), as otherwise 
users might be digging through the Python/NumPy docs to look for the 
description of msqrt or nsqrt.

Guy

-- 
Guy K. Kloss
Institute of Information and Mathematical Sciences
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