Re: [SciPy-user] Questions about Line Integral Convolution tutorial
Anne, As long as some notation of the issue is available in this forum, that should help a number of users wanting to work with it for now. Is there any protocol for others updating the Wiki entry? I've just joined Scipy but been a member of AstroPy since its inception - but I have yet to write or update a Wiki page. I'm still getting some type of 'shifting' of my dataset after running LIC, so I need to examine the Cabral reference more closely. I think I'm still missing something. Thanks, Tom
2008/11/24 Bridgman, William T. <William.T.Bridgman@nasa.gov>:
I had found the Cabral reference, as well as a few others that described either different algorithms or described them in radically different notation.
I implemented my code based on the Cabral reference. Currently it does not quite do everything they recommend.
Transposing the texture solved my crashing problem. That seems kind of counter-intuitive. Perhaps it could be noted in the docs somewhere or changed in the interface?
Looks like a bug. Indeed I only tested my code with square arrays. It wasn't really ready for release, but there was some interest, and I have no time at all to work on it just now.
Anne
-- Dr. William T."Tom" Bridgman Scientific Visualization Studio Global Science & Technology, Inc. NASA/Goddard Space Flight Center Email: William.T.Bridgman@nasa.gov Code 610.3 Phone: 301-286-1346 Greenbelt, MD 20771 FAX: 301-286-1634 http://svs.gsfc.nasa.gov/
2008/11/24 Bridgman, William T. <William.T.Bridgman@nasa.gov>:
Is there any protocol for others updating the Wiki entry? I've just joined Scipy but been a member of AstroPy since its inception - but I have yet to write or update a Wiki page.
Generally the protocol is "go right ahead, it's version-controlled". Just out of curiosity, what were you hoping to use the LIC code for?
I'm still getting some type of 'shifting' of my dataset after running LIC, so I need to examine the Cabral reference more closely. I think I'm still missing something.
It is totally possible there's a big in my code. In particular David Huard pointed out there may be an indexing bug that means that instead of integrating forward, it integraes backward twice. If the code works right, you shouldn't see any shifting, but Cabral et al. point out that it's very important the algorithm and kernel be symmetric, or you can get circles turning into spirals and the like. Anne
participants (2)
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Anne Archibald -
Bridgman, William T.