channelflow.org

====== Differences ====== This shows you the differences between two versions of the page.

--- docs:utils:poincare [2009/02/23 12:25]
gibson
+++ docs:utils:poincare [2010/02/02 07:55] (current)
@@ Line 1: / Line 1: @@
 ====== poincare ======
-compute crossings of a Poincare section in a pre-computed trajectory
+Compute crossings of a Poincare section in a pre-computed trajectory. The Poincare condition is %%(u(t) - ueqb, e) == 0%%, i.e. the displacement from a given point %%ueqb%% is orthogonal to a direction %%e%%. The program checks for changes in sign in the inner product in the stored trajectory (with large %%dT%%, and when it finds one, goes back and reintegrates with small %%dt%%, and then does quadratic interpolation when the fine-scale trajectory recrosses the section.
 ===== usage =====
 <code>
-  poincare -T0 0 -T1 400 -d datadir <ueqb> <ue>
+  poincare -T0 0 -T1 400 -d datadir ueqb.ff e.ff
 </code>
-computes the crossings of the Poincare section %%(u(t)-ueqb, e) == 0%% and saves them in a %%poincare/%% directory.
+reads a trajectory u0, u1, ..., u400 stored in %%datadir%%, computes the crossings of the Poincare section %%(u(t)-ueqb, e) == 0%%, and saves them in a %%poincare/%% directory.
 ===== options =====
@@ Line 50: / Line 50: @@
 </code>
+===== Hiccups =====
+:-) Hey John, I was wondering if there was any particular reason you put the cfpause() line in your code other than it was helpful in writing the code. --- //[[dustin.spieker@gatech.edu|Dustin Spieker]] 2009-03-02 10:24//