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LSODE Failure!
From: |
ben |
Subject: |
LSODE Failure! |
Date: |
Wed, 7 Jan 2015 02:28:45 -0800 (PST) |
Hi!!
I have a big problem with an sistem of four ODE. The problem is the two last
ODE, i don't have no idea why they failure...
This is the code:
function funcio=f(x,t)
%Constantes:
G=6.67384*10^-11;
Mt=5.9722*10^24;
Ml=7.349*10^22;
m=100;
d=384400000;
w=2.66*10^-6;
funcio=zeros(4,1);
funcio(1)=x(3)/m;
funcio(2)=x(4)/m*x(1)*x(1);
funcio(3)=(x(4)*x(4)/m*x(1)*x(1)*x(1))-(G*Mt*m/x(1)*x(1))-(G*Ml*m*(x(1)-d*cos(x(2)-w*t)))/(sqrt(x(1)*x(1)+d*d-2*x(1)*d*cos(x(2)-w*t)))^3
;
funcio(4)=-G*Ml*m*x(1)*d*sin(x(2)-w*t)/(sqrt(x(1)*x(1)+d*d-2*x(1)*d*cos(x(2)-w*t)))^3
;
endfunction
%Vector de condiciones iniciales, tiempo y funcion 'lsode':
m=100;
R=6371000;
fi0=41.61;
v0=11000;
theta0=23.6;
x0=[R,fi0,m*v0*cos(theta0-fi0),m*R*v0*sin(theta0-fi0)];
t=[0:50:9000];
y=lsode('f',x0,t);
%Plot de la trayectoria:
polar(y(:,2),y(:,1))
When i delete the funcio(3), and funcio(4), the program does't advise me,
but when i run the full code the warning apears.
error: lsode: repeated convergence failures (t = 5.57884e-018; perhaps bad J
acobian supplied or wrong choice of integration method or tolerances)
>>>
I don't know how to solve the problem, may could be because the las two
ODE's ara depending whit time?
Thank.
Ben
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