How to make .m file

Hello.

I made a separate .m file for me to evaluate using ode45 but i got an error. This is my .m file.

function ndot= volterra_allelo(t,n)
global r1 k1 alpha12 gamma12 r2 k2 alpha21 gamma21;
ndot(1,1)= r1*n(1)*((k1-alpha12*n(2)-gamma12*n(1)*n(2)/k1));
ndot(2,1)= r2*n(2)*((k2-alpha21*n(1)-gamma21*n(1)*n(2)/k2));

i am ruuning this using the code:

[time n]=ode45('volterra_allelo',[0 10],[n1hat_n/2;n2hat_n/2];

I have some values for r1 k1 alpha12 gamma12 r2 k2 alpha 21 gamma21 and n1hat_n and n2hat_n.

when i run the ode comman, i got an error.

I think i have errors in the .m file. please help me.

Answer 1

[madhan ravi]

% r1,k1,alpha12,gamma12,r2,k2,alpha21,gamma21 provide all the values here ,parametrized your function rather than using global

[time n]=ode45(@(t,n)volterra_allelo(t,n,r1,k1,alpha12,gamma12,r2,k2,alpha21,gamma21),[0 10],[n1hat_n/2;n2hat_n/2]; %function call

function ndot= volterra_allelo(t,n,r1,k1,alpha12,gamma12,r2,k2,alpha21,gamma21)   %function definition
ndot=zeros(2,1);
ndot(1)= r1*n(1)*((k1-alpha12*n(2)-gamma12*n(1)*n(2)/k1));
ndot(2)= r2*n(2)*((k2-alpha21*n(1)-gamma21*n(1)*n(2)/k2));
end