Re: column-oriented data
Re: column-oriented data
- Subject: Re: column-oriented data
- From: David Phillip Oster <email@hidden>
- Date: Thu, 17 Aug 2006 21:43:13 -0700
At Thu, 17 Aug 2006 12:06:09 -0400, "Paul L. Gribble" <email@hidden> wrote:
Does anyone know of any example code out there of using core data for
numerical (e.g. column-oriented) datasets? Is this even a good idea?
On the one hand core data seems powerful enough to handle large
database-oriented datasets, so those involving columns of floats
shouldn't be a big deal. I just wonder if it is overkill.
On a related note for displaying columnar numerical data to the user
in a gui, is NSTable appropriate?
Columnar numeric data, such as f(x,y) = z, for say 1024x1024 is
commonly called an NSImageRep. It would be pretty silly to allocate a
million NSNumbers, one for each pixel. if it is just one column, you
might think of it as an oscilloscope trace. Zoom out, and for each
scanline, instead of drawing a point, you draw a line segment from
min x to min y of that band's map to the underlying data.
You can use the dataSource interface of NSTableView to point into an
ordinary C array of ints or floats. NSTableView will handle millions
of entries just fine, but you may want to think about what user
intefaces make sense.
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