# issue in solving set of ode's

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Bathala Teja on 22 Sep 2021
Here i gave my script with dummy R, G, L, g matrices(because of confidentiality).
Here iam forming the matrices G, L and g interms of theta and extracting these variable matrices to solve set of odes. In that iam substituting 26th solution(y(26)) in place of theta. I attached photo better look into that.
I want to know whether the steps from "commonvars" are correct or not.
syms phi theta
a = 2*phi+5;
b = diff(a);
R = rand(27, 27);
Gi = b*cos(theta)*rand(25, 25);
G = [Gi zeros(25, 2);
zeros(2, 27)]
Li = sin(theta+5)*rand(25, 25);
L = [Li zeros(25, 2);
zeros(2, 25) [1 0; 0 1]]
g = (sin(theta)+cos(theta+2))*rand(25, 25)
commonvars = unique([symvar(G), symvar(L), symvar(g)]); %probably just theta
Gfun = matlabFunction(G, 'vars', commonvars);
Lfun = matlabFunction(L, 'vars', commonvars);
gfun = matlabFunction(g, 'vars', commonvars);
tspan = [0 1];
myfun = @(t,y)scriptname(t, y, R, Gfun, Lfun, gfun);
y0 = zeros(27, 1);
[t, y] = ode45(myfun, tspan, y0);
h = figure;
% plot
for i=1:25
plot(t,y(:, i));
end
function dydt = scriptname(t, y, R, Gfun, Lfun, gfun)
f = 60; % frequency
Wr = 2*pi*f; % Angular velocity of rotor
inertia = 0.05;
% evaluation of g (numerical) with theta = y(27)
gn = gfun(y(27))
for i=1:25
I(i,1)=y(i);
end
Te = 1/2*I'*gn*I
V=[sqrt(2)*400/sqrt(3)*cos(Wr*t);
sqrt(2)*400/sqrt(3)*cos(Wr*t+2.*pi/3.);
sqrt(2)*400/sqrt(3)*cos(Wr*t-2.*pi/3.);
zeros(Nr+1, 1);
0;
Te/inertia;
y(26)];
% evaluation of G and L (numerical) with theta = y(27)
Gn = Gfun(y(27))
Ln = Lfun(y(27))
dydt = Ln\(V-R*y-y(26)*Gn*y)
end
Actually the code was running fine and giving waveforms also but not as expected.
I want to make sure whether steps for ode calculation are correct or not.

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