Which approach is useful here to get a plot?

I have this function with two input parameters

I'm used to graphing functions with a single parameter.

But how can you get an output with two parameters?

How will it be passed to the function if I create two arrays

for each input parameter? I'd want to have input in the

range [0,1]. Is there another example?

Answer 1

[KSSV]

Check and then use. I have quickly typed it without much thought.

n1 = linspace(0,1) ;
n2 = linspace(0,1) ;

n = cat(3,n1,n2) ;

% First summation 
T1 = zeros(size(n1)) ;
for i = 1:2
    T1 = T1 + -1/2*n(:,:,i)+1/4*n(:,:,i).^4 ;
end
% Second summation 
for i = 1:2
    T2 = n(:,:,i).^2 ; 
    for j = 1:2
        if j ~= i 
            T2 = T2.*n(:,:,j).^2 ;
        end
    end
end

iwant = T1+T2 ;

[Trim Dim]

I am not sure about the output of your code but

the expected output is like that

[KSSV]

Perfect..

n1 = linspace(0,1) ;
n2 = linspace(0,1) ;

[n1,n2] = meshgrid(n1,n2) ; 

n = cat(3,n1,n2) ;

% First summation 
T1 = zeros(size(n1)) ;
for i = 1:2
    T1 = T1 + -1/2*n(:,:,i)+1/4*n(:,:,i).^4 ;
end
% Second summation 
for i = 1:2
    T2 = n(:,:,i).^2 ; 
    for j = 1:2
        if j ~= i 
            T2 = T2.*n(:,:,j).^2 ;
        end
    end
end

iwant = T1+T2 ;
surf(n1,n2,iwant)

[Trim Dim]

Although the output is very similar but in the expected output

(as in my attachment) there is a bump in the center

and the edges show minima at n1=1 and n1=0 and also at

n2=1 and n2=0.