[SciPy-user] [SciPy-dev] default dtype

[Alan G Isaac]

On Mon, 02 Jan 2006, Ed Schofield apparently wrote: 
> Perhaps the most compelling argument against an integer 
> default is the current behaviour with unsafe casting: 

This is an important argument, but the most compelling 
argument I believe is that the integer arrays are
- unlikely to be expected by the inexperienced (or those 
  with experience in say GAUSS or Matlab)
- less often wanted (or so I believe; is this wrong?)
- likely to be set explicitly in any case by those who 
  really want them

So the principle of least surprise suggests a float default, 
and I believe the most common use case does as well.

Following on the problem of surprise, even if unsafe casting 
is eliminated (and it may be viewed as a feature by some!),
new users will still be unpleasantly surprised.  I.e.,
new users will be surprised even if there is an error 
message instead of
>>> x=ones((2,2))
>>> print 3.14*x
[[ 3.14, 3.14,]
 [ 3.14, 3.14,]]
>>> x[0,0]=x[0,0]*3.14
>>> print x
[[3,1,]
 [1,1,]]

Cheers,
Alan Isaac