Thanks so much. That'll be great. I'm really looking forwards to trying lsmlib with your cython wrappers.
Regards, Yunbo On Feb 10, 2012, at 11:18 AM, Daniel Wheeler wrote: > On Thu, Feb 9, 2012 at 4:56 PM, wang yunbo <[email protected]> wrote: > Hi, > > 1. when I look at the 'data' file and checked some point which suppose to be > at the surface e.g (50, 25), (62, 71), the results are like 0.0 or 0.7 (not > 0.04 as expected). That's where I get confused. How can I reach my > expectation? > > I don't think you can with the current implementation in FiPy. The > calcDistanceFunction method is only first order accurate I believe and hence > the difficulties calculating the curvature accurately. The applications in > FiPy don't use higher derivatives so get away with first order accuracy. The > curvature calculation is second order accurate, but the underlying > calculation of the distance function is not. Hence the issues. Basically, > FiPy as it stands is not accurate enough for this. > > 2. The shape of my plot is quite wavy with many wiggles, not concentric > rings as expected. > > I'm moving towards using lsmlib > <http://ktchu.serendipityresearch.org/software/lsmlib/index.html>, which I > believe has second order accuracy for the distance function calculation and > is also way faster than FiPy. At the moment I have cython wrappers for > calcDistanceFunction2d, calcEikonalEquation2d and calcExtensionFields2d, > which seem to work though I haven't tested extensively. My hope is to replace > all the level set functionality in FiPy with the cython lsmlib calls. I'm > happy to share the cython wrappers with you if you wish. > > In short I recommend that you give lsmlib a shot and then use the my cython > wrappers to integrate with python. > > Cheers. > > -- > Daniel Wheeler > _______________________________________________ > fipy mailing list > [email protected] > http://www.ctcms.nist.gov/fipy > [ NIST internal ONLY: https://email.nist.gov/mailman/listinfo/fipy ]
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