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--- gtspring2009:research_projects:hyatt:blog [2009/03/27 09:32]
john_h
+++ gtspring2009:research_projects:hyatt:blog [2010/02/02 07:55] (current)
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 -//[[jshyatt@gatech.edu|John Hyatt]] 2009-03-26 23:01//
-Update - After 2 successful Newton iterations (taking all night), GMRes for the 3rd iteration mysteriously failed.  This is the first time that even one iteration for this field worked, though - but I will try a new random field today and during the wedding I'm going to this weekend.
+{{gtspring2009:jshyatt.jpg?24}} Update - After 2 successful Newton iterations (taking all night), GMRes for the 3rd iteration mysteriously failed.  This is the first time that even one iteration for this field worked, though - but I will try a new random field today and during the wedding I'm going to this weekend.
 -//[[jshyatt@gatech.edu|John Hyatt]] 2009-03-27 12:32//
+{{gtspring2009:jshyatt.jpg?24}} The simulation I started Friday is still running.  I'll update when it's done.
+-//[[jshyatt@gatech.edu|John Hyatt]] 2009-03-30 10:13//
+{{gtspring2009:gibson.png?24}} Responses.
+. The Unix "time" command will tell you how much CPU time a process consumes. Usage: "time findorbit ....".
+For more run "man time" at the Unix prompt.
+. You can determine the distance between two fields with [[docs:utils:l2dist|L2Dist]].
+Are you starting your searches using output from [[docs:utils:randomfield]]? It would be better to use
+initial guesses randomly distributed within the invariant measure of the flow, by taking samples of
+turbulent simulations.
+. findorbit.cpp stores convergence data in the file %%convergence.asc%%. This is an ASCII file (same
+as .txt). Should be readable in Windows as well as cygwin. The first line in the file tells you
+what the columns are; for more on the meaning of those columns you can look in the source code
+and particularly the comments that explain the algorithm.
+// John Gibson 2009-04-01 //
+{{gtspring2009:jshyatt.jpg?24}} 1. Thanks,
+. Yes I am (at least this time) - Dr Cvitanovic suggested I do in order to get a feel for what can go wrong with findorbit, and that kind of thing.  I was going to ask you about that more sophisticated stuff as soon as this one is done running...unfortunately, my computer blue-screened on me for completely un-Channelflow-related reasons and killed my findorbit run.  But (and here I feel like I've learned something useful) I figured out that I can just start the run again from the most recent output from the findorbit command (unewtN.ff, N being the most recent run).  I can also try now with a smaller GMRes - I upped it some because I was still having trouble with it not converging, but it took forever.  Now maybe that it has run some I can try with smaller T?
+. OK, will look at this tomorrow.
+// [[jshyatt@gatech.edu|John Hyatt]] 2009-04-03 2:50//
+{{gtspring2009:jshyatt.jpg?24}}  Questions for Predrag, John G, or whoever:
+) I have an exam on Monday so I'll be pretty busy until then, but I'd like to start looking for equilibria now/soon.  I think that means I need to talk to John G about how to find a good starting point, but maybe other people can help?  I also need to get a PACE account, which I think Predrag told me he could help with.
+) When Channelflow gives output for the findorbit command it produces a bunch of .ff files from the original field (one for each Newton step).  I wanted to make sure I understand this right:  each of these is the previous field plus the adjustment from the Newton step, right?  i.e. it isn't just a .ff file containing the adjustment.  This means that if it hasn't converged by the time the program terminates, you can just take the latest output and use it as a new input to keep going, right?  //John Hyatt 2009-04-09 13:47//
+{{gtspring2009:gibson.png?24}} I am at your disposal: johnfgibson on skype, 617 441-3609 by phone. If you want to
+talk during the day and I'm not on skype, send me an email and I'll turn it on. Yes, the unewt3.ff file is the previous field plus the adjustment. It's the current best approximation to the solution. // John Gibson 2009-04-09 15:21 EST//

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