can I apply a for loop inside the function so that I can make my program short?

Question

SAHIL SAHOO 2022-7-31

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1771485-can-i-apply-a-for-loop-inside-the-function-so-that-i-can-make-my-program-short

编辑： Torsten 2022-8-3

ti = 0;
tf = 10E-6;
tspan = [ti tf];
a = 0.6;
n = 0.05;
tc = 10E-9;
r = 1.5;
F = 10;
 
f = @(t,y) [  
                  (-1/(2*tc)).*(1 - r/(1+ (y(1)^2)./F)).*y(1) + (n/(2*tc)).*((cos(y(6))).*y(2)) ;
                  (-1/(2*tc)).*(1 - r/(1+ (y(2)^2)./F)).*y(2) + (n/(2*tc)).*((cos(y(7))).*y(3) + (cos(y(6))).*y(1));
                  (-1/(2*tc)).*(1 - r/(1+ (y(3)^2)./F)).*y(3) + (n/(2*tc)).*((cos(y(8))).*y(4) + (cos(y(7))).*y(2));
                  (-1/(2*tc)).*(1 - r/(1+ (y(4)^2)./F)).*y(4) + (n/(2*tc)).*((cos(y(10))).*y(5) + (cos(y(8))).*y(8));
                  (-1/(2*tc)).*(1 - r/(1+ (y(5)^2)./F)).*y(5) + (n/(2*tc)).*((cos(y(9))).*y(4));
               
                
                  (a./(2*tc)).*(  r/(1 + (y(2)^2)./F) - r/(1 + (y(1)^2)./F) ) + (n/(2*tc)).*(((y(3)./y(2)).*sin(y(7))) - (y(2)./y(1) + y(1)./y(2) ).*sin(y(6)) );
                  (a./(2*tc)).*(  r/(1 + (y(3)^2)./F) - r/(1 + (y(2)^2)./F) ) + (n/(2*tc)).*(((y(4)./y(3)).*sin(y(8))) - (y(3)./y(2) + y(2)./y(3) ).*sin(y(7)) + (y(1)./y(2)).*sin(y(6)));
                   (a./(2*tc)).*(  r/(1 + (y(4)^2)./F) - r/(1 + (y(3)^2)./F) ) + (n/(2*tc)).*(((y(5)./y(4)).*sin(y(8))) - (y(4)./y(3) + y(3)./y(4) ).*sin(y(8)) + (y(2)./y(3)).*sin(y(6)));
                   (a./(2*tc)).*(  r/(1 + (y(5)^2)./F) - r/(1 + (y(4)^2)./F) ) + (n/(2*tc)).*(((y(3)./y(4)).*sin(y(8))) - (y(5)./y(4) + y(4)./y(5) ).*sin(y(9)));
                      (a./(2*tc)).*(  - r/(1 + (y(5)^2)./F) ) + (n/(2*tc)).*((y(4)./y(5)).*sin(y(9)));
               ];   

can I apply here the "for loop" inside where the function define. so the program will get short.

I wrote 10 equation in this, what if I want 20 equation ? can I apply for loop in this or any method.

    [time,Y] = ode45(f,tspan,[1;1;1;1;1;1;1;1;1;1].*10E-6);
plot(time,Y(:,6))
hold on
plot(time,Y(:,7))
plot(time,Y(:,8))
plot(time,Y(:,9))
hold off

4 个评论
显示 2更早的评论隐藏 2更早的评论

per isakson 2022-8-3

Now I think I understand your question.

Are there typos in your anonymous function? This looks suspect.

e.g. "y(8)" in three rows.

Does your anonymous function agree with the equations in your comment?

Torsten 2022-8-3

编辑：Torsten 2022-8-3

For more details (especially how A_0, phi_0, A_N+1 and phi_N+1 are defined), see

https://de.mathworks.com/matlabcentral/answers/1771405-there-are-two-coupled-differential-equation-i-try-to-solve-that-differential-for-the-i-1-to-5-b?s_tid=prof_contriblnk

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Answer 1

Torsten 2022-8-3

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1771485-can-i-apply-a-for-loop-inside-the-function-so-that-i-can-make-my-program-short#answer_1020565

编辑：Torsten 2022-8-3

在 MATLAB Online 中打开

N = 5;
ti = 0;
tf = 10E-6;
tspan = [ti tf];
[time,Y] = ode45(@(t,y)f(t,y,N),tspan,[1;1;1;1;1;1;1;1;1;1].*10E-6);
function dy = f(t,y,N)
  a = 0.6;
  n = 0.05;
  tc = 10E-9;
  r = 1.5;
  F = 10;
  A = y(1:N);
  phi = y(N+1:2*N);
  dA = zeros(N,1);
  dphi = zeros(N,1);
  dA(1) = ...;
  dphi(1) = ...;
  for i = 2:N-1
    dA(i) = ...;
    dphi(i) = ...;
  end
  dA(N) = ...;
  dphi(N) = ...;
  dy = [dA;dphi];
end