Creating 3D Plot using Surf

Hello,

I am trying to create a plot in 3D using "surf" command with specific conditions. I would like to plot "g" depending on two variables, the value of "gamma" and "f" with speicfic value of "n". The 1D array of gamma is defined as follows, and also I need to see the result (the value of "g") only when n=3. I have tried to modify my program in several ways such as using "if" statement, but they do not work. Basically, the following code produces a plot for all possible values of "n" (from 1 to 5), but what I need to obtain is "g" that depends on "gamma" and "f" when "n=3". Would you hellp me to design the program code fulfilling the two conditions?

format long e

n=1:1:5;
m=1:1:10;
alpha=0.01;
A=zeros(length(n),length(m));
B=zeros(length(n),length(m));
f=zeros(length(n),length(m));
g=zeros(length(n),length(m));
gamma=zeros(length(m));


for i=1:1:length(n)
    for j=1:1:length(m)  
        gamma(j)=10^(j-1);          
        A(i,j)=i.^2/j.^3;
        B(i,j)=A(i,j)./(alpha+i);         
        f(i,j)=B(i,j)./(A(i,j)+i);
        g(i,j)=A(i,j)./j;              
        %fprintf('%d %.10e %.10e %.10e\n',i,gamma(j),f(i,j),g(i,j)); 
    end
    %fprintf('\n');
end

for i=1:1:length(n)
    for j=1:1:length(m)        
        [X,Y]=meshgrid(1:length(n),1:length(m)); 
        if(i==3) <===== % Does not work!
            surf(Y,f',g'); <===== % How can I incorporate "gamma" rather than "Y"? 
            xlabel('gamma');
            ylabel('f');
            zlabel('g');  
        end
    end
end

Answer 1

[KALYAN ACHARJYA]

format long e
n=1:1:5;
m=1:1:10;
alpha=0.01;
A=zeros(length(n),length(m));
B=zeros(length(n),length(m));
f=zeros(length(n),length(m));
g=zeros(length(n),length(m));
gamma=zeros(length(m));
for i=1:1:length(n)
    for j=1:1:length(m)  
        gamma(j)=10^(j-1);          
        A(i,j)=i.^2/j.^3;
        B(i,j)=A(i,j)./(alpha+i);         
        f(i,j)=B(i,j)./(A(i,j)+i);
        g(i,j)=A(i,j)./j;              
        %fprintf('%d %.10e %.10e %.10e\n',i,gamma(j),f(i,j),g(i,j)); 
    end
    %fprintf('\n');
end
for i=1:1:length(n)
    for j=1:1:length(m)        
        [X,Y]=meshgrid(1:length(n),1:length(m)); 
        if i==3
            surf(Y',f,g); 
            xlabel('gamma');
            ylabel('f');
            zlabel('g');  
        end
    end
end

Answer 2

[Star Strider]

One possibility is to preallocate ‘gamma’ as a vector, since it appears to be such in the rest of your code:

gamma = zeros(size(m));

then create it as a matrix in your surf call:

surf((ones(5,1)*gamma)',f',g')

If you want ‘gamma’ to be a matrix of different row elements, you will need to assign it as such, since at present, you are assigning it as a vector. My version of your surf call simply creates it as a matrix of identical rows.