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Formatted print

From: Dorci Smith
Subject: Formatted print
Date: Fri, 26 Jul 2002 10:50:55 -0500

I'm working on a double pendulum problem to solve with a Runge-Kutta 4
in Octave.  I have been able to run the scripts and plot the results,
but I
would like to see the data Octave computed.  I have two variables (T,X)
where T
is a column vector that holds all time increments (0.00, 0.01, 0.02,
...) and X
is an Nx2 matrix that holds the first and second derivatives of the y"
being solved in the Runge-Kutta 4 script.  Octave prints the values held
in these
variables to the screen when I run the script, but I would like to
output them to
a file in the following format:
T       X
0.00    value  value
0.01    value  value
100.00  value  value
I have used the "disp()" function, but it returns a new line after each
it prints.  I tried using the format:
for i=0:1000
disp(T(i), X(i,1), X(i,2));
but this did not work.
I originally tried to print as:
printf('%f %f\n', T, X);
but this only printed the column vector T and beneath it, the Nx2 matrix
instead of printing them side by side as shown above.
I also tired:
for i=0:1000
printf(%f %f %f\n', T(i), X(i,1), X(i,2));
This never printed any values, but if I manually input a value into the
arrays, it
would print the appropriate value:
code:   printf(%f %f %f\n', T(1), X(1,1), X(1,2));
output: 0.00 value value
One other format I tried was:
printf('%f %f %f\n', T(:), X(:,1), X(:,2));
however, this just printed out the T column vector as:
0.00   0.01  0.02
0.03   0.04   ...
99.98  99.99  100.00
After the T vector was printed, the first column of the X matrix was
printed in
the same format and after it was finished, the second column of the X
matrix was

My objective in formatting the output like this is to compare the
produced by Octave with the Gnuplot created by another program.  I want
to put
plots on the same graph and see where they begin do differ.
I am a new Octave user and do not know the little tricks.  If anyone has
advice I would really appreciate it.

Dorci Smith
Co-op Tier II
Titan Systems Corporation
Astronautics Engineering Division

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