I'm running it on laptop Windows XP with Python 2.4.3, numpy 1.0.1, and PySparse 1.0.

It's good to know that it probably isn't a code problem. The fact that you mentioned bad memory reminds me that the laptop indeed had some memory problems a while ago....if this keeps happening, maybe I'll run it on a stable linux box instead. Thanks very much for hinting at it!

Elizabeth

Jonathan Guyer wrote:


On Aug 16, 2007, at 7:34 PM, Elizabeth Tseng wrote:

OK. Here's a reduced form of the code that still produces errors from time to time. Sometimes it finishes without problems, sometimes the variable values become 1.#QNAN (when I print out C_1b), and sometimes I get an error at line:

Res.append(eq_Ab.sweep(var=Ab, boundaryConditions=Ab_BCs, dt=dt))

and the error is: IndexError: id1 is not the same size as b (line 322, sparseMatrix.py)

I've run your script several times on both a PPC Mac OS X machine (10.4.10) with Python 2.4.4., NumPy 1.0.2, and PySparse 1.0 and on a i686 Debian Linux machine (3.1) with Python 2.3.5, NumPy 1.0.1, and PySparse 1.0. I'm running FiPy 1.2 on both because I assume that's what you're running, but I wouldn't expect it to matter for this particular issue. I don't get any NaNs or errors for either one.

What is your configuration?

For the record, I don't see any obvious issues in your code. From the way you were describing it before, I thought that you might be building a matrix that amounted to 0 == 0, which might cause a problem, but I don't believe you are. I have no idea why you'd get errors sometimes and not others; your code should do exactly the same thing every time you run it; in my case, the numbers are even identical to at least 10 significant figures between the two fairly disparate architectures I described above. It almost makes me suspect bad memory or a loose chip or something.





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