OpenCV any Users on List?
It has been suggested to me to look into OpenCV for some matrix math capabilities. Anyone use it? Can it handle double precision complex numbers? From reading the documentation, it leads me to think it could, if one defines the matrix as double precision 2 channel. OpenCV appears to require a good C++ background, which I don't have now. Is it ugly to use? Do I want to go there? Any advice? (Besides drowning myself now?) -Bruce ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: OpenCV any Users on List?
On Fri, May 21, 2010 at 6:37 PM, Bruce Labitt bruce.lab...@myfairpoint.net wrote: OpenCV appears to require a good C++ background, which I don't have now. ... Any advice? Tell your employer you need some C++ training in order to do your job effectively. Or if you're afraid they'll terminate you and hire someone else, seek learning on your own time and dime. -- Ben ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Shot in the dark: Anyone ever use CLAPACK routines?
bruce.lab...@autoliv.com wrote:
gnhlug-discuss-boun...@mail.gnhlug.org wrote on 05/19/2010 02:34:19 PM:
snip a ton o' stuff
Comment on my own post. Probably nothing is wrong with MY CODE.
http://icl.cs.utk.edu/lapack-forum/viewtopic.php?f=2t=745
The claim is that zgesvd_ function hangs. The fix is allegedly to
modify
the make.inc file for CLAPACK.
The change is adding -ffloat-store to the end of NOOPT.
NOOPT = -O0 -I$(TOPDIR)/INCLUDE -fPIC -ffloat-store
Hope that fixes it. I'll find out in 4+ hours!
-Bruce
Of course it didn't work :( Sounded too good to be true, and it was!
I did find out that Scipy.linalg.svd used LAPACK not CLAPACK.
In [4]: source( svd )
In file: /usr/lib/python2.6/dist-packages/scipy/linalg/decomp.py
def svd(a,full_matrices=1,compute_uv=1,overwrite_a=0):
snip
# A hack until full_matrices == 0 support is fixed here.
if full_matrices == 0:
import numpy.linalg
return numpy.linalg.svd(a, full_matrices=0, compute_uv=compute_uv)
a1 = asarray_chkfinite(a)
if len(a1.shape) != 2:
raise ValueError, 'expected matrix'
m,n = a1.shape
overwrite_a = overwrite_a or (_datanotshared(a1,a))
gesdd, = get_lapack_funcs(('gesdd',),(a1,))
if gesdd.module_name[:7] == 'flapack':
lwork = calc_lwork.gesdd(gesdd.prefix,m,n,compute_uv)[1]
u,s,v,info = gesdd(a1,compute_uv = compute_uv, lwork = lwork,
overwrite_a = overwrite_a)
else: # 'clapack'
raise NotImplementedError,'calling gesdd from %s' %
(gesdd.module_name)
if info0: raise LinAlgError, SVD did not converge
if info0: raise ValueError,\
'illegal value in %-th argument of internal gesdd'%(-info)
if compute_uv:
return u,s,v
else:
return s
Hmm... I wonder if CLAPACK have been rigorously tested, like (f)LAPACK
has... I guess that scipy/numpy did not think so...
arggghh...
Accckk, time to get more familiar with valgrind... Nuts, I thought
this was all going to be straight forward... Give me python any day!
-Bruce
Not too much to report. I even re-compiled ATLAS LAPACK allowing gcc
gfortran and got my example code to build. Same problem with the 9x9
matrix. The 2x2 double complex matrix svd worked!
I do have to say the interface to LAPACK is much better than CLAPACK.
(C or C++ calling FORTRAN) I can go back to my old (bad) habits of
using bits of C++ to help make the code easier to follow.
In numpy/scipy the code computed the svd with no problem.
Not too much activity at the lapack-forum. :( Since the academic term
ended recently at UT Knoxville, maybe everyone is on vacation...
-Bruce
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Re: OpenCV any Users on List?
bruce.lab...@myfairpoint.net wrote: OpenCV appears to require a good C++ background, which I don't have now. ... Any advice? Tell your employer you need some C++ training in order to do your job effectively. Or if you're afraid they'll terminate you and hire someone else, seek learning on your own time and dime. Let me stress that the only familiarity I have with OpenCV is what I gained just now when I spent approx three minutes glancing at this: http://www.cs.iit.edu/~agam/cs512/lect-notes/opencv-intro/index.html ...but based on that exhaustive analysis and on your postings on this channel I'd have to say that you should charge boldly forward because OpenCV does not seem like a very challenging or esoteric example of C++. It looks to me like the hardest part of OpenCV would be the matrix math concepts (independent of programming language) and if you're comfortable with that then OpenCV would mostly feel like plain old C to you. ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: OpenCV any Users on List?
Benjamin Scott wrote: On Fri, May 21, 2010 at 6:37 PM, Bruce Labitt bruce.lab...@myfairpoint.net wrote: OpenCV appears to require a good C++ background, which I don't have now. ... Any advice? Tell your employer you need some C++ training in order to do your job effectively. Or if you're afraid they'll terminate you and hire someone else, seek learning on your own time and dime. -- Ben It isn't like I can do NO C++, I did write an FFT server running on a QS22 with OpenMP (multi-core threads) FFTW and communicated via sockets. I wrote that in C++ creating a sockets/com class, and a command processor/sequencer, class, etc. However, I don't think in C++. Training wouldn't hurt! (I don't know where the time would come from, but it seems everyone has that problem.) Oh, and a lot of practice. I don't know about you, but the only way things actually get into my cortex matter, is practice, practice, practice, in that order. As for hiring someone else, I've begged my management to get me some help here. Surprising to some, I actually know a few things :) However, being a hotshot C++ programmer is not one of those things yet. I'm working on it, groaning a lot though Sorry to subject you to it... Umm, so, do you know anything about OpenCV? Good? Bad? Easy to use? Stinks for insert x ? -Bruce ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: OpenCV any Users on List?
Michael ODonnell wrote: bruce.lab...@myfairpoint.net wrote: OpenCV appears to require a good C++ background, which I don't have now. ... Any advice? Tell your employer you need some C++ training in order to do your job effectively. Or if you're afraid they'll terminate you and hire someone else, seek learning on your own time and dime. Let me stress that the only familiarity I have with OpenCV is what I gained just now when I spent approx three minutes glancing at this: http://www.cs.iit.edu/~agam/cs512/lect-notes/opencv-intro/index.html ...but based on that exhaustive analysis and on your postings on this channel I'd have to say that you should charge boldly forward because OpenCV does not seem like a very challenging or esoteric example of C++. It looks to me like the hardest part of OpenCV would be the matrix math concepts (independent of programming language) and if you're comfortable with that then OpenCV would mostly feel like plain old C to you. ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ Yes, that is the extent of my analysis to date also :) Same website. I'd like to know the under pinnings of the OpenCV matrix math routines. I strongly suspect it is just ATLAS/BLAS and LAPACK, the same blasted packages that I have not been able to figure out on my own! It irritates the heck out of me!!! Especially when others have apparently figured it out. The matrix math is not hard for me now (you should have asked me 2 months ago, I hadn't looked at that stuff in over 20, umm, no, 30 years!). It appears that OpenCV could work. But, it looked like CLAPACK was the answer to my dreams too. I'm wary of undertaking the OpenCV learning curve, and finding a dead end. (But if one does the same thing one always does, then nothing will change...) So I guess I'm off on another adventure. I'm so close to getting this stuff off the ground, I can almost taste it. I can only hope the taste of 'victory' will be sweet enough to erase the memory of the stench of the trenches. -Bruce ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
