[Numpy-discussion] tril, triu, document/ implementation conflict

[eat]

Hi,

On Wed, Jan 26, 2011 at 2:35 PM, <josef.pktd at gmail.com> wrote:

>  On Wed, Jan 26, 2011 at 7:22 AM, eat <e.antero.tammi at gmail.com> wrote:
> > Hi,
> >
> > I just noticed a document/ implementation conflict with tril and triu.
> > According tril documentation it should return of same shape and data-type
> as
> > called. But this is not the case at least with dtype bool.
> >
> > The input shape is referred as (M, N) in tril and triu, but as (N, M) in
> > tri.
> > Inconsistent?
>
Any comments about the names for rows and cols. I prefer (M, N).

>  >
> > Also I'm not very happy with the performance, at least dtype bool can be
> > accelerated as follows.
> >
> > In []: M= ones((2000, 3000), dtype= bool)
> > In []: timeit triu(M)
> > 10 loops, best of 3: 173 ms per loop
> > In []: timeit triu_(M)
> > 10 loops, best of 3: 107 ms per loop
> >
> > In []: M= asarray(M, dtype= int)
> > In []: timeit triu(M)
> > 10 loops, best of 3: 160 ms per loop
> > In []: timeit triu_(M)
> > 10 loops, best of 3: 163 ms per loop
> >
> > In []: M= asarray(M, dtype= float)
> > In []: timeit triu(M)
> > 10 loops, best of 3: 195 ms per loop
> > In []: timeit triu_(M)
> > 10 loops, best of 3: 157 ms per loop
> >
> > I have attached a crude 'fix' incase someone is interested.
>
> You could open a ticket for this.
>
> just one comment:
> I don't think this is readable, especially if we only look at the
> source of the function with np.source
>
> out= mul(ge(so(ar(m.shape[0]), ar(m.shape[1])), -k), m)
>
> from np.source(np.tri) with numpy 1.5.1
> m = greater_equal(subtract.outer(arange(N), arange(M)),-k)

I agree, thats why I called it crude. Before opening a ticket I'll try to
figure out if there exists somewhere in numpy .astype functionality, but not
copying if allready proper dtype.

Also I'm afraid that I can't produce sufficient testing.

Regards, eat

>
> Josef
>
> >
> > Regards,
> > eat
> > _______________________________________________
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> > NumPy-Discussion at scipy.org
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> >
> >
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