During calculations , a constant is obtained instead of a function

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Dmitry
Dmitry 2022-12-28
评论： Torsten 2022-12-28
I have a complex function that depends on 'd' and 'n' F(n,d) I need to sum a series over 'n' and plot F(d).
I know that after summing by 'n' I should get a function F(d) which is rapidly oscillating and decaying. But after summing, I get a constant that does not depend on d.
My cod:
%% initial conditions
global t k0 h_bar ksi m E;
Ef = 2.77*10^3;
Kb = physconst('boltzmann'); % 1.38*10^(-23)
D = 5:5.1:50;
m = 9.1093837*10^(-31);
Tc = 1.2;
t = 1;
ksi = 10^(-9);
d = D./ksi;
E = Ef/(pi*Kb*Tc);
h_bar = (1.0545726*10^(-34));
k0 = (ksi/h_bar)*sqrt(2.*m.*pi.*Kb.*Tc);
C_2 = 0;
for n = 0:49
C_2 = C_2 + (1/(2.*n+1)).*k0.*real(sqrt(E+1i.*(2.*n+1))-((1+1i)./sqrt(2)).*sqrt(2.*n+1)); % константа
end
%% calculation
F = f_calc(d);
plot(d,F,'o');
%% F(d)
function F = f_calc(d)
global t k0 h_bar ksi m;
F = 0;
for n = 0:49
F = F + 1/(2*n+1).*imag(f_lg(n,t)+1i*d.*k0.*((f_p1(n)-f_p2(n))./2)+1i*f_arg_1(n,d)-1i*f_arg_2(n,d));
end
F = -(1./d).*F;
plot(d,F,'o');
end
function p1 = f_p1(n)
global t;
p1 = ((1+1i)./sqrt(2)).*sqrt(t.*(2.*n+1));
end
function p2 = f_p2(n)
global t E;
p2 = sqrt(E+1i.*t.*(2.*n+1));
end
function n_lg = f_lg(n,d)
global t k0;
arg_of_lg = (1+exp(-1i*d*k0.*f_p1(n)))/(1+exp(-1i*d*k0.*f_p2(n)));
n_lg = log(abs(arg_of_lg));
end
function arg_1 = f_arg_1(n,d)
global t k0;
arg_1 = angle(1+exp(-1i*d*k0.*f_p1(n)));
end
function arg_2 = f_arg_2(n,d)
global t k0;
arg_2 = angle(1+exp(-1i*d*k0.*f_p2(n)));
end
  1 个评论
Torsten
Torsten 2022-12-28
But after summing, I get a constant that does not depend on d.
You get a vector of values that depends on d. But the difference between its elements is very small compared to their absolute value (1e11).

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