How to correctly change a variable from a single number to an array.

7 Ansichten (letzte 30 Tage)
Hello, I oringinally wrote this matlab code to model the FitzHugh-Nagumo action potential. Now I'm trying to modify the model to get a string of action potentials. To do this I need to change all the state variables to array shown below:
These equations:
% Fitzhugh-Nagoma model parameters
e=0.03; k=3; a=0.05;
Are changed to this:
% Fitzhugh-Nagoma model parameters
e=[0.03 0.03]; k=[3 3]; a=[0.05 0.05];
However when I do this the code doesn't run. Can somebody explain what needs to change in the rest of the code to get it to work? Thanks a lot!
%Clear command window and workspace
clear
close all
clc
% Fitzhugh-Nagoma model parameters
e=[0.03 0.03]; k=[3 3]; a=[0.05 0.05];
i = 0.001;
figure(1);
hold on
u=zeros(100000,1);
v=zeros(100000,1);
t=zeros(100000,1);
% Initial conditions:
u(1)=0.6;
v(1)=0.0;
t(1)=0;
dt=0.001;
%==========================================================================
% Forvard Euler Method, for soluing the ODE
%==========================================================================
for i=1:1:500000
t(i+1)=t(i)+dt;
u(i+1) = u(i)+ dt*((1/e)*((k*u(i)*(u(i)-a)*(1-u(i)))-v(i)));
v(i+1) = v(i)+ dt*(u(i)-v(i));
end
% Getting the plot
figure(1);
plot(t,u)
legend('u','Trajectory')
title('Time Series Plot')
xlabel('Time')
ylabel('u')
xlim([0 5])

Akzeptierte Antwort

Jan
Jan am 24 Nov. 2018
Bearbeitet: Jan am 24 Nov. 2018
e = [0.03 0.035]; k = [3 3]; a = [0.05 0.05];
n = 500000;
u = zeros(n, 2);
v = zeros(n, 2);
t = zeros(n, 1);
% Initial conditions:
u(1, :) = 0.6;
v(1, :) = 0.0;
t(1) = 0;
dt = 0.00001;
% Forward Euler Method, for soluing the ODE
for i = 1:n - 1
t(i+1) = t(i) + dt;
u(i+1, :) = u(i, :) + dt * ((1 ./ e) .* ...
((k .* u(i, :) .* (u(i, :) - a) .* (1 - u(i, :))) - v(i, :)));
v(i+1, :) = v(i, :) + dt * (u(i, :) - v(i, :));
end
figure;
plot(t, u)
All you have to do is to define u and v as matrices instead of vectors and to change \ and * to the elementwise operations .\ and .* . Then acces the subvectors as u(i, :) instead of u(i).

Weitere Antworten (0)

Kategorien

Mehr zu Loops and Conditional Statements finden Sie in Help Center und File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by