Hi Deen,
The updated code:
……
for i1 = r:numel(t)
t2 = ts*i1;
…….
err = 1;
i2 = 0;
while err > 0.03
i2 = i2 + 1;
fz = z0 - Znonlin(i1-1);
Fa(i1) = ts*fz.sin(pp1(t2)).exp(n1(t2));
FFa(i1) = FFa(i1-1)+Fa(i1);
Fb(i1) = ts*fz.cos(pp1(t2)).exp(n1(t2));
FFb(i1) = FFb(i1-1)+Fb(i1);
d1 = exp(-n1*t2).*sin(pp1*t2);
d2 = exp(-n1*t2).*cos(pp1*t2);
u(i2) = pp2*(FFb(i1).(Bo.*d1) - FFa(i1).(Bo.*d2));
Znonlin(i1)= zlin_a(1,i1) + u(i2);
if i2 != 1
u_new = u(i2);
u_old = u(i2-1);
u_dif = u_new- u_old;
err = u_dif/ u_new;
end
Znonlin(i1)
End
As you are incrementing i2 at the beginning of the while loop, you have to initialize the value of i2 to 0. And since there is no error for the first element, we consider that condition and not calculate the error for u(1).
