How can I plot the functions in my code according to theta?

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Burak 2013-4-9

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/71337-how-can-i-plot-the-functions-in-my-code-according-to-theta

Here is my code.

clear all
format long
tic
N_cut=20;
eps0=(10^-9)/(36*pi);
mu0=4*pi*10^-7;
epsr1=1.;
epsr2=2.;
mur1=1.;
mur2=1.;
eps1=epsr1*eps0;
eps2=epsr2*eps0;
mu1=mur1*mu0;
mu2=mur2*mu0;
freq=299.7925*10^6;
omeg=2*pi*freq;
k=omeg*sqrt(eps1*mu1);
lambda=2*pi/k;
phi=45;
R=1.1;
for n=1:N_cut
      bes_kur1(n)=sqrt(pi.*k.*R./2).*besselj(n+0.5,k.*R);
      han_kur1(n)=sqrt(pi.*k.*R./2).*besselh(n+0.5,2,k.*R);
      bes_kur_der1(n)=-n.*sqrt(pi.*k./(2.*R)).*besselj(n+0.5,k.*R)+k.*sqrt(pi.*k.*R./2).*besselj(n-0.5,k.*R);
      han_kur_der1(n)=-n.*sqrt(pi.*k./(2.*R)).*besselh(n+0.5,2,k.*R)+k.*sqrt(pi.*k.*R/2).*besselh(n-0.5,2,k.*R);
      han_kur_dd(n)=sqrt(pi.*k.*R./2).*besselh(n+2.5,2,k.*R)-sqrt(pi./(2.*k.*R)).*(2.*n+3).*besselh(n+1.5,2,k.*R)+sqrt(pi./(2.*(k.*R).^3)).*...
              n.*(n+1).*besselh(n+0.5,2,k.*R);
       a(n)=(1i.^(-n)).*(2.*n+1)./(n.*(n+1));
       b(n)=(-a(n)).*bes_kur_der1(n)./han_kur_der1(n);
       c(n)=(-a(n)).*bes_kur1(n)./han_kur1(n);
          L1=legendre(n,cosd(theta));
          L11=legendre(n-1,cosd(theta));
          L2(n)=L1(2);
          if n==1
          L3(n)=0.;
          else
          L3(n)=L11(2);
          end
      L2_der(n)=(-(n+1).*L3(n)+n.*cosd(theta)).*L2(n)/sind(theta);
      E_r=((-1i.*cosd(phi).*b(n).*L3(n).*(han_kur_dd(n)+han_kur1(n))));
      E_theta=(cosd(phi)./(k.*R)).*((1i)*b(n)*han_kur_der1(n).*sin(theta).*L2_der(n)-c(n).*han_kur1(n)*(L3(n)./sin(theta)));
      E_phi=(sin(phi))./(k.*R).*(((1i).*b(n).*han_kur_der1(n).*(L3(n)./(sin(theta))))-(c(n).*han_kur1(n).*sin(theta)).*L2_der(n));
end
F_Er=sum(E_r);
F_Etheta=sum(E_theta);
F_Ephi=sum(E_phi);
figure
plot(theta,abs(F_Er)),grid on
hold
figure
plot(theta,abs(F_Etheta)),grid on
hold
figure
plot(theta,abs(F_Ephi)),grid on
hold

3 个评论
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Burak 2013-4-9

yes exactly I want that , F_Er,F_Etheta , F_Ephi has to be function of theta.

Walter Roberson 2013-4-9

Hmmm, okay, but are you going to be doing anything with the formulas afterwards that you need them to be in function form? Or do you just need to be able to plot, in which case you could possibly proceed with numeric theta?

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采纳的回答

Walter Roberson 2013-4-9

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/71337-how-can-i-plot-the-functions-in-my-code-according-to-theta#answer_81662

在 MATLAB Online 中打开

At the beginning of the code, put in

syms theta

then before you go to plot, you need to choose specific theta to plot for, such as by

Thetas = linspace(0, 2*pi, 100);
val_F_Er = double( subs(F_er, theta, Thetas) );
val_F_Etheta = double( subs(F_Etheta, theta, Thetas) );
val_F_Ephi = double( subs(F_Ephi, theta, Thetas) );
figure
plot(Thetas, abs(val_F_Er));
figure
plot(Thetas, abs(val_F_Etheta));
figure
plot(Thetas, abs(val_F_Ephi));