# Looping of more than one first order equations in in function file that can be updated for different value variable parameter

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Rajni kant kumar on 4 Apr 2021
Answered: darova on 6 Apr 2021
I want to feed component of vector C (1by20) one by for each loop of system first orde differential equation in order to numerically integrating the whole (320by1) equations simultaneously. i am not able to loop it currectly kindly help me.
function [f]=Loop_stiffness_nonlin12(t,y,C,w,phia,phid,E1,lmda1,m0,e,N)
%% sinusoidal force
% W=2*N*pi/60;
%
% p1=m0*e*(W)^2*sin(W*t);
%
% p1=p1/10;
f= zeros(320,1);
for j=1:16:305
f(j)=y(1+j);
f(1+j)= -w(1)^2*y(j)-lmda1*y(1+j)-C(1,i)*phid(1)*(phid(1)*y(j)-y(2+j))^3;
f(4+j)=y(5+j);
f(5+j)= -w(2)^2*y(4+j)-lmda1*y(5+j)-C(1,i)*phid(2)*((phid(1)*y(j)+phid(2)*y(4+j))-y(2+j))^3;
f(6+j)=y(7+j);
f(7+j)= -w(3)^2*y(6+j)-lmda1*y(7+j)-C(1,i)*phid(3)*((phid(1)*y(j)+phid(2)*y(4+j);
f(8+j)=y(9+j);
f(9+j)= -w(4)^2*y(8+j)-lmda1*y(9+j)-C(1,i)*phid(4)*((phid(1)*y(j);
f(10+j)=y(11+j);
f(11+j)= -w(5)^2*y(10+j)-lmda1*y(11+j)-C(1,i)*phid(5)*((phid(1)*y(j)+phid(2)*y(4+j));
f(2+j)= y(3+j);
f(3+j)= (C(1,i)/E1)*((phid(1)*y(j)+phid(2)*y(4+j)+phid(3)*y(6+j)+phid(4)*y(8+j)+phid(5)*y(10+j))-y(2+j))^3+(lmda1/E1)*((phid(1)*y(1+j)+phid(2)*y(5+j)
end
end
end

darova on 6 Apr 2021
See this example
f = @(t,x,a) [x(2); x(1)-a*sin(x(1))];
a = rand(10,1); % parameter
cmap = jet(10);
for i = 1:length(a)
[t,x] = ode45(f,[0 2],[1 1],[],a(i));
line(t,x(:,1),'color',cmap(i,:))
end