% example of integrating single ODE with matlab
% A -> B essentially irreversible rxn in an isothermal, isobaric PFR

% x is the dependent variable, fractional conversion of "A"
% tau is the independent variable, space time

% declare "global" variables whose values are shared with file "deriv01.m"
global k
 
k = 1;       % set rate constant used in "deriv01.m"

tauSpan = [1 10];  % set span of tau
x0 = [0];    % set initial conversion

% call ode45 integrator
% 'deriv01' is defined in the file "deriv01.m"
% this is a user-written "m" file containing the derivative equation

[tau,x] = ode45('deriv01', tauSpan, x0);

% all the integration is finished now, so plot and save results

plot(tau,x)
title('example of integrating one ODE')
xlabel('tau (space time)')
ylabel('x (fractional conversion)')

info = 'press any key to continue'
pause

% put tau and x into one array so disk file
%  will be in correct format for loading into graphing program

u = [tau, x];

info = 'Saving data tab-delimited text file "data01.temp"'
% col 1 = tau, col 2 = fractional conversion x.
% IMPORT as Text file with Delimeter = Tab

save data01.temp u -ascii -tabs

info = '*** ex01 finished ***'