[Visualpython-users] vector converted to numpy.ndarray

[Aaron M. <ajm...@al...>]

Hi VPython folks,

I was attempting to run the contributed script
http://vpython.org/contributed/bodies.py and I get an error... I have
tracked it down to the fact that the dot product dot(a,b) between two
vectors returns a type of numpy.float64 and when I multiply this by a vector
I get back an array instead of a vector.

A simple example that generates an error for me:

from visual import *
a=vector(1,0,0)
b=dot(a,a)*a
b.mag

Here is the error:
Traceback (most recent call last):
  File "Untitled", line 4
    b.mag
AttributeError: 'numpy.ndarray' object has no attribute 'mag'

Of course, by assigning b as vector(dot(a,a)*a) we fix this, but it seems
this should not be needed.  Is this a bug?

Thanks,
Aaron
Python 2.6.2 with VPython 5.12

------------------------------------------------------
Aaron J. Miller, Ph.D.
Department of Physics
328 Palenske Hall
Albion College, Albion, MI 49224