[mesa-users] mesa bug fix release -- 7503

[Bill Paxton]

Hello again,

Yes, it was just last week that I did a release.  But when a bug is reported, found, and fixed, I'll go ahead and do a bug fix release as soon as possible to give you the choice of getting the fixed version or letting it go until next major release (in 2 months or so at the current rate).  If I didn't make the quick bug fix release, I'd be making that choice for you, and that's a big "No No".  I fix the bugs (only fair since I create them in the 1st place), but you decide what's important for you such as whether a small bug fix is important enough for your application to make you go to the trouble of getting a new release.

This is a relatively small and well hidden bug -- so well hidden that it had gone undetected by the test_suite for the releases starting last October.  On Tuesday, all of 4 days after the release of 7499, I got an email from Jieun Choi reporting "wiggles in tracks".  Since Jieun is an expert user, she didn't just leave it at "something is wrong, please fix it".  She didn't even stop with sending an inlist and instructions adequate to reproduce the problem.  She sent a plot illustrating the problem by comparing a bad new track to a good old one (attached).  Then comes the really impressive part -- she checked releases starting from when she knew it worked and found the exact release where the problem was first introduced (6794). Then she provided an inlist edited to work with 6794 and another edited to work with the next release after that (7184).   Given such a great start, I was able to check unreleased intermediate versions to find where the bug entered, then which module, which file, and which edit was the source.  Turns out I had put a "gradL" where I should have written "grada" in one place in the convective mixing routine in the mlt module.  Here's the plot that Jieun sent -- this is a track for a 1Msun from pre-ms to TAMS; the wiggles show Teff bouncing around a bit during the main sequence. 

-Bill


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