CODEWITHSUNDEEP
matlabode45
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Reputation: 11

Not enough input arguments for ode45 function

I am setting up a function that can solve the following differential equation for a laser system with the listed parameters. Whenever I run my code though, I keep getting errors that there are not enough input arguments for the equation (dydt). I am unsure where the fault in the code is occurring, but I believe it may have something to do with how I defined y. I expect to get a gaussian distribution in a plot, but the code keeps stopping at dydt. It does not process the variables. Thank you! 

        function dydt = 4_Lasers(t,y)

        beta=1;
        p0=10;


        tau2=1e-7;

        t = 1;
        taupulse=tau2*100000;

        taup=tau2/100;

        p=p0*exp(-(t/taupulse)^2);

        dydt = [(1/tau2)*(p-y(1)-y(1)*y(2)); (y(2)/taup)* 
        (y(1)-1)+beta*y(1)/tau2];

        end

        clear; close all;
        [t,y] = ode45(@4_Lasers,[0 1e-6],[0; 0]);
         plot(t,y(:,1),'r',t,y(:,2),'b')
        title('p0=10,taupulse/tau2=1.5,tau2/taup=100');
        xlabel('Time t');
        ylabel('Amplitude');
        legend('Photodensity','population inversion')

Upvotes: 1

Views: 991

Answers (1)

rinkert
rinkert

Reputation: 6863

Cannot reproduce with this code:

clear; close all;
[t,y] = ode45(@Lasers,[0 1e-6],[0 0]);
plot(t,y(:,1),'r',t,y(:,2),'b')
title('p0=10,taupulse/tau2=1.5,tau2/taup=100');
xlabel('Time t');
ylabel('Amplitude');
legend('Photodensity','population inversion')



function dydt = Lasers(t,y)

    beta=1;
    p0=10;

    tau2=1e-7;

    t = 1;
    taupulse=tau2*100000;

    taup=tau2/100;

    p=p0*exp(-(t/taupulse)^2);

    dydt = [(1/tau2)*(p-y(1)-y(1)*y(2)); (y(2)/taup)*(y(1)-1)+beta*y(1)/tau2];

end

Upvotes: 1

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