[Numpy-discussion] what is the best way to do a statistical mode operation?

Gordon Wrigley gordon@tolomea....
Sun Oct 3 16:56:06 CDT 2010


> How many point do you have in np.unique(array) ?

43 currently

On Sun, Oct 3, 2010 at 11:55 PM, <josef.pktd@gmail.com> wrote:

> On Sun, Oct 3, 2010 at 8:41 AM, Gordon Wrigley <gordon@tolomea.com> wrote:
> > I have an array of uint8's that has a shape of X*Y*Z*8, I would like to
> > calculate modes along the 8 axis so that I end up with an array that has
> the
> > shape X*Y*Z and is full of modes.
> > I'm having problems finding a good way of doing this. My attempts at
> solving
> > this using bincount or histogram produce an intermediate array that is
> 32x
> > the size of my input data and somewhat larger than I have the memory to
> deal
> > with.
> > Can anyone suggest a good way to produce modes over sets of 8 bytes?
> > Also in the instance where there are multiple modes for a particular set
> I'm
> > happy for it to pick any one arbitrarily.
>
> What's the range of integers? How many point do you have in
> np.unique(array) ?
>
> bincount, for example, uses range(arr.max()+1) as set of points.
>
> looping over 8 values would be fast, but the intermediate arrays would
> depend on the number of unique values.
> I would try to use a dictionary.
>
> Josef
>
>
> > G
> >
> >
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