PLOT surface using 3 vectors of same length (NEED HELP!!!)

please i have managed to make 3 vectors but i want to plot a 3D surface. what am i surposed to do?

b=0;
for i = -200:1:200  
    for j = -90:0.45:90
        b=1+b;   
        lambda(b) = i;
        beta(b) = j;   
        lambdai =(((lambda(b)+(0.08*beta(b))))*((beta(b)^3)+1))/((beta(b)^3)+1-(0.035*(lambda(b)+(0.08*beta(b)))));   
        pwrcoff = 0.5109*((116/lambdai)-(0.4*beta(b))-5)*exp(-21/lambdai);   
        P(b) = 0.5*1.2754*12469*63*55^2*pwrcoff;
    end
end

Answer 1

[Star Strider]

The code produces vectors, so I would simply reshape them, using the number of unique elements in ‘i’ to determine one of the dimensions —

b=0;
 for i = -200:1:200  
   for j = -90:0.45:90
    b=1+b;   
    lambda(b) = i;
    beta(b) = j;   
    lambdai =(((lambda(b)+(0.08*beta(b))))*((beta(b)^3)+1))/((beta(b)^3)+1-(0.035*(lambda(b)+(0.08*beta(b)))));   
    pwrcoff = 0.5109*((116/lambdai)-(0.4*beta(b))-5)*exp(-21/lambdai);   
    P(b) = 0.5*1.2754*12469*63*55^2*pwrcoff;
   end
 end
 
%  lambda
%  beta
%  P
 
RowSize = numel(-200:1:200);
  
 lambdam = reshape(lambda, RowSize,[]);
 betam = reshape(beta, RowSize, []);
 Pm = reshape(P, RowSize,[]);
 Pm = Pm .* ((Pm >= -50) & (Pm <= +5));
 
 figure
 surf(lambdam, betam, Pm, 'EdgeColor','none')
 grid on
 xlabel('\lambda')
 ylabel('\beta')
 zlabel('P')

.

Answer 2

[Bjorn Gustavsson]

You can use multiple indices in the variables you create. For example if you do things like this:

b=0;
for i = -200:1:200  
    for j = -90:0.45:90
        b=1+b;   
        lambda(i,j) = i;
    end
end

You will create 2-D arrays, that you can then use with for example pcolor.

HTH