[Numpy-discussion] step paramter for linspace

Sebastian Berg sebastian@sipsolutions....
Fri Mar 1 06:58:38 CST 2013


On Fri, 2013-03-01 at 13:44 +0100, Sebastian Berg wrote:
> On Fri, 2013-03-01 at 12:33 +0000, Henry Gomersall wrote:
> > On Fri, 2013-03-01 at 13:25 +0100, Sebastian Berg wrote:
> > > there has been a request on the issue tracker for a step parameter to
> > > linspace. This is of course tricky with the imprecision of floating
> > > point numbers.
> > 
> > How is that different to arange? Either you specify the number of points
> > with linspace, or you specify the step with arange. Is there a third
> > option?
> > 
> > My usual hack to deal with the numerical bounds issue is to add/subtract
> > half the step.
> > 
> 
> There is not much. It does that half step logic for you, and you
> actually know that the end point is exact (since linspace makes sure of
> that).
> 
> In arange, the start and step are exact. In linspace the start and stop
> are exact (even with a given step, it would vary on the order of
> floating point accuracy).
> 
> Maybe the larger point is the hope that by adding this to linspace it is
> easier to get new users to use it and avoid pitfalls of arange with
> floating points when you are not aware of that half step thing.
> 

That said, I am honestly not sure this is worth it. I guess I might use
it once in a while, but overall probably hardly at all and it is easy to
do something else...

> > Henry
> > 
> > 
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> > 
> 
> 
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