On Mon, Jan 19, 2009 at 12:25 AM, Stéfan van der Walt <stefan@sun.ac.za> wrote:
2009/1/18 David Cournapeau <david@ar.media.kyoto-u.ac.jp>:
I needed DCT transforms, so I finished implementing them in scipy (both single and double prec):
http://projects.scipy.org/scipy/scipy/browser/trunk/scipy/fftpack/realtransf...
- dct3 and dct2 are inverse from each other (compared to dct/idct notation of matlab; dct2(x, norm=ortho) is the same as matlab dct(x), and dct3(x, norm='ortho') is the same as matlab idct.
While this naming is accurate, it is confusing in relation to the other FFT functions. I prefer "dct" and "idct".
Calling them dct/idct can be confusing as well: dct3(dct2(x)) != x (because of normalization). And what to do for dct1/dct4 - in theory, there are 8 dct possible, and 8 dst as well (I have no use for dst, so I did not implement them, but they should follow at some point). Maybe the type could be an argument: dct(..., type=number) ? David