[petsc-users] how to get full trajectory from TS into petsc binary

[Ed Bueler]

Dear PETSc --

I have a short C ode code that uses TS to solve  y' = g(t,y)  where y(t) is
a 2-dim'l vector.  My code defaults to -ts_type rk so it does adaptive
time-stepping; thus using -ts_monitor shows times at stdout:

$ ./ode -ts_monitor
solving from t0 = 0.000 with initial time step dt = 0.10000 ...
0 TS dt 0.1 time 0.
1 TS dt 0.170141 time 0.1
2 TS dt 0.169917 time 0.270141
3 TS dt 0.171145 time 0.440058
4 TS dt 0.173931 time 0.611203
5 TS dt 0.178719 time 0.785134
6 TS dt 0.0361473 time 0.963853
7 TS dt 0.188252 time 1.
error at tf = 1.000 :  |y-y_exact|_inf = 0.000144484

I want to output the trajectory in PETSc binary and plot it in python using
bin/PetscBinaryIO.py.  Clearly I need the times shown above to do that.

Note "-ts_monitor_solution binary:XX" gives me a binary file with only y
values in it, but not the corresponding times.

My question is, how to get those times in either the same binary file
(preferred) or separate binary files?  I have tried

$ ./ode -ts_monitor binary:foo.dat    # invalid
$ ./ode -ts_monitor_solution binary:bar.dat   # no t in file
$ ./ode -ts_monitor_solution binary:baz.dat -ts_save_trajectory   # no t in
file

without success.  (I am not sure what the boolean option
-ts_save_trajectory does, by the way.)

Thanks!

Ed

PS Sorry if this is a "RTFM" question, but so far I can't find the
documentation.


-- 
Ed Bueler
Dept of Math and Stat and Geophysical Institute
University of Alaska Fairbanks
Fairbanks, AK 99775-6660
301C Chapman and 410D Elvey
907 474-7693 and 907 474-7199  (fax 907 474-5394)
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