Hi, I've just started using Octave and I'd like to use it to solve and plot a system of differential equations, but I keep getting the same error which I don't understand. What have I done wrong in my code?(adsbygoogle = window.adsbygoogle || []).push({});

Outline:

Initial conditions

x1 = 1

x2 = 1.27 x 10^-6

x3 = 0

t = 0 - 140 days

Equations

dx1 = -0.5*x(1)*x(2)

dx2 = 0.5*x(1)*x(2) - 0.25*x(3)

dx3 = 0.25*x(2)

Code:

%function

function xdot = m (x, t)

xdot = zeros (3,1);

xdot(1) = -0.5*x(1)*x(2);

xdot(2) = 0.5*x(1)*x(2) - 0.25*x(3);

xdot(3) = 0.25*x(2);

endfunction

%initial conditions

x0 = [1;1.27e-06;0];

t = linspace (0,140);

%solve

y = lsode ("m",x0,t)

%plot

plot (y,t)

the error I get says

lsode: repeated convergence failures

Thanks!!

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# Octave differential equations

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