Having problem plotting with surfc function

phi21 = linspace(-Tn,Tn,ns);
phi31 = linspace(-Tn,Tn,ns);
Tn=100;
ns=30;
P1=0;
alpha = 0;
beta = 0;
gama = 0;
[phi_21,phi_31] = meshgrid(phi21,phi31);
  n=0;
  for n=1:(2*n-1):21
      P1(n)=(k12.*cos(alpha*pi*n/360).*cos(beta*pi*n/360).*sin(phi_21*pi*n/180))+(k13.*cos(alpha*pi*n/360).*cos(gama*pi*n/360).*sin(phi_31*pi*n/180))
      P1=P1+P1(n);
end
surfc(phi_21,phi_31,P1); colorbar;

I would like to surfc plot of equation P1 with respect to phi_21 and phi_31 upto 21st harmonic where n=1,3,5,7... this shows a dimension error like this "The surface Z must contain more than one row or column". Could anyone please help me with this?

[KSSV]

P1 should me a matrix.

[Mukul]

How can I modify the code then?

Answer 1

[Image Analyst]

You need to define Tn, ns, k12, and k13. Then get rid of the for loop.

% Guess at values.
Tn = .5;
ns = 100;
k12=4;
k13 = 3;

phi21 = linspace(-Tn,Tn,ns);
phi31 = linspace(-Tn,Tn,ns);
Tn=100;
ns=30;
P1=0;
alpha = 0;
beta = 0;
gama = 0;
[phi_21, phi_31] = meshgrid(phi21, phi31);
n = phi_21;
P1=(k12.*cos(alpha*pi*n/360).*cos(beta*pi*n/360).*sin(phi_21*pi*n/180))+...
  (k13.*cos(alpha*pi*n/360).*cos(gama*pi*n/360).*sin(phi_31*pi*n/180));
surfc(phi_21,phi_31,P1, 'EdgeColor', 'none'); 
colorbar;
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);

[Mukul]

Thanks for your effort. However, I couldn't understand why n=phi_21 ( this is angle and has defined earlier in the code). n is the harmonic number and should be 1.3.5.7....21. so I used the for loop in my code.

    % n = phi_21;

Could you please advise on it?

[Image Analyst]

Perhaps you should explain in words more precisely what you want. How many surfaces do you want to generate?

[Mukul]

I would like to generate one surface plot for the equation below P equation

   P1(n)=(k12.*cos(alpha*pi*n/360).*cos(beta*pi*n/360).*sin(phi_21*pi*n/180))+(k13.*cos(alpha*pi*n/360).*cos(gama*pi*n/360).*sin(phi_31*pi*n/180))

where the value of n should change such that n=1.3.5.7.9.11......21. So I will get P1(1), P1(3), P1(5), P1(7), P1(9).....P1(21) Now P=P1(1)+P1(3)+P1(5)+P1(7)+P1(9).....+P1(21) then I want to do surfc plot of P versus phi_12 and Phi_13

[Image Analyst]

What values do you have for k12 and k13?

Try this:

% Guess at values.
Tn=100;
ns=30;
k12=4;
k13 = 3;

phi21 = linspace(-Tn,Tn,ns);
phi31 = linspace(-Tn,Tn,ns);
Tn=100;
ns=30;
alpha = 0;
beta = 0;
gama = 0;
[phi_21, phi_31] = meshgrid(phi21, phi31);
P = zeros(size(phi_21));
for n = 1 : 21
  thisP=(k12.*cos(alpha*pi*n/360).*cos(beta*pi*n/360).*sin(phi_21*pi*n/180))+...
    (k13.*cos(alpha*pi*n/360).*cos(gama*pi*n/360).*sin(phi_31*pi*n/180));
  P = P + thisP;
  subplot(5, 5, n);
  surfc(phi_21,phi_31, thisP, 'EdgeColor', 'none');
  drawnow;
end
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);

% Plot the sum of all the P's
figure;
surfc(phi_21,phi_31,P, 'EdgeColor', 'none');
colorbar;
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);

[Mukul]

Much appreciated your effort.