Re: surface cdata property restricted to double or uint8

[Jaroslav Hajek]

On Mon, Aug 30, 2010 at 10:09 AM, Michael Goffioul
<address@hidden> wrote:
> On Mon, Aug 30, 2010 at 6:12 AM, Jaroslav Hajek <address@hidden> wrote:
>> If I see right, however, you save the space for lda doubles, but there
>> are already two arrays of 3*lda doubles around (cmapv and av), which
>> means you'll save 14% memory at best. That is really not much in
>> Octave's context. I would likewise prefer the simpler change.
>
> Don't think it's true. cmapv is just a pointer to the internal figure colormap
> array, which already exists (no temp array created) and is *not* of size 
> 3*lda.
> "NDArray a" is actually the only array created in that function.
>

Whether or not an array is temporary is not that much relevant; the
important point is that the array is hanging around. If I'm working
with arrays of 10^7 doubles, saving a temp of 10^6 doubles is
marginal, even though it may be a huge saving otherwise. But you're
indeed right that cmapv is not 3*lda long. So put 25% there.

> That function was written with both memory and performance in mind, as it
> called on every redraw (this also means for instance when rotation), and
> the amount of data (cdata) can be quite large.
>

OK, I wasn't questioning the original code's performance.


-- 
RNDr. Jaroslav Hajek, PhD
computing expert & GNU Octave developer
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz