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Solving an ODE numerically .. What is the problem in my code?

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Esraa Abdelkhaleq
Esraa Abdelkhaleq 2016-8-21
评论： Torsten 2016-8-22
Hello,
I want to solve this ODE numerically..
dq_pl/dt=f_plc*R_c*N_c0*exp(K_gr*t)+f_plh*R_h*N_h0-K_el*q_pl(t).
Where the letters following the underscore signs are subscripts, the parameters values are:
fplc=0.1 ; Rc=4.5*10^-5 ; Nc0=1 ; Kgr= 5.78*10^-3 ; fplh*Rh*Nh=4.56*10^3 ; Kel= 0.11 ;
tspan = [0 10^10] , qpl0 = 0
I wrote:
function [t,qpl] = call_dstate()
tspan = [0 10^10]; % set time interval
qpl0 = 0; % set initial condition
% dstate evaluates r.h.s. of the ode
[t,qpl] = ode45( @dstate ,tspan ,qpl0);
plot(t,qpl)
disp([t,qpl]) % displays t and qpl(t)
function dqpldt = dstate (t,qpl)
fplc=0.1 ; Rc=4.5*10^-5 ; Nc0=1 ; Kgr= 5.78*10^-3 ; fplh*Rh*Nh=4.56*10^3 ; Kel= 0.11 ;
dqpldt=fplc*Rc*Nc0*exp(Kgr*t)+fplh*Rh*Nh0-Kel*qpl;
end
end
Thanks in advance.

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采纳的回答

Torsten
Torsten 2016-8-22
Use fplh_Rh_Nh instead of fplh*Rh*Nh:
fplh_Rh_Nh = 4.56e3;
...
dqpldt=fplc*Rc*Nc0*exp(Kgr*t)+fplh_Rh_Nh0-Kel*qpl
Best wishes
Torsten.
  2 个评论
Esraa Abdelkhaleq
Esraa Abdelkhaleq 2016-8-22
编辑：Esraa Abdelkhaleq 2016-8-22
Dear Torsten,
Thanks a lot.
I did what you said but the same error appeared !
May I have a problem in the version itself? how can I check that everything is OK in the version? I use 2008a version.

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