hi , i'm trying to solve an ode , my program works but it makes 1 hours... and o don't understand why
Here is my fonction to define my ode :
function dy=f_mixte(t,y)
global Q b K n E sg0 epoint C1 C2 D1 D2
f=abs(y(1)-y(3)-y(4))-Q*(1-exp(-b*y(2)))-sg0;
if f<0
dy(2)=0;
else
dy(2)=(f/K).^n;
end
dy(5)=sign(y(1)-y(3)-y(4));
dy(1)=E*(epoint-dy(5));
dy(3)=C1*dy(5)-D1*y(3)*dy(2);
dy(4)=C2*dy(5)-D2*y(4)*dy(2);
dy=dy';
end
And here my main function :
global Q b K n E sg0 epoint C1 C2 D1 D2 sigma0
b=5;
Q=-150 ;
E=140000;
sigma0=200;
K=800;
n=6;
epoint=0.001;
sg0=200;
C1=300000;
C2=25000;
D1=2000;
D2=200;
[T,a]=ode45('f_mixte',[0 10],[0 0 0 0 0])
thanks for your help :)
[Merged information from duplicate Question]
hi !
I would like to improve my program, i'm want it be faster and make better virtual mode memory management :
global Q b K n E sg0 epoint C1 C2 D1 D2
b=5;
Q=-150 ;
E=140000;
sigma0=200;
K=800;
n=6;
epoint=0.001;
C1=300000;
C2=25000;
D1=2000;
D2=200;
sg0=200;
[t,y]=ode45('f_mixte',[0 10],[0 0 0 0 0]);
sigma1=y(:,1);
ep1=y(:,5);
e1=ep1+sigma1/E;
tic
hold on
for w = 0:100
Ti=10;
Tf=30;
L=length(y);
epoint=-epoint;
[t,y]=ode45('f_mixte',[Ti Tf],[y(L,:)]);
Ti=Tf;
Tf=Ti+20;
sigma2=y(:,1);
ep2=y(:,5);
e2=ep2+sigma2/E;
L=length(y);
plot(e1,sigma1,e2,sigma2)
end
hold off
toc
and my main function
function dy=f_mixte(t,y)
global Q b K n E sg0 epoint C1 C2 D1 D2
R=Q*(1-exp(-b*y(2)));
f=abs(y(1)-y(3)-y(4))-R-sg0;
if f<0
dy(2)=0;
else
dy(2)=(f/K)^n;
end
dy(5)=sign(y(1)-y(3)-y(4))*dy(2);
dy(1)=E*(epoint-dy(5));
dy(3)=C1*dy(5)-D1*y(3)*dy(2);
dy(4)=C2*dy(5)-D2*y(4)*dy(2);
dy=dy';
end
