Somewhere in your code you defined a fitness function which assumes that inputs j and k are integers
function fitness = Ft(x,j,k,t)
%Some computations
fitness = ...;
end
Now you want to define a fitness value for j and k not being integers by weighting the values of Ft in the rectangle surrounding the point (j,k):
function fitness = interFt(Ft, x, j, k, t)
% Find the floor and ceiling for j and k
j_floor = floor(j);
j_ceil = ceil(j);
k_floor = floor(k);
k_ceil = ceil(k);
% Calculate probabilities based on the distance from the actual values
p_j_floor = j_ceil - j;
p_j_ceil = j - j_floor;
p_k_floor = k_ceil - k;
p_k_ceil = k - k_floor;
% Calculate the weighted fitness for each combination
fitness = 0;
fitness = fitness + p_j_floor * p_k_floor * Ft(x, j_floor, k_floor, t);
fitness = fitness + p_j_floor * p_k_ceil * Ft(x, j_floor, k_ceil, t);
fitness = fitness + p_j_ceil * p_k_floor * Ft(x, j_ceil, k_floor, t);
fitness = fitness + p_j_ceil * p_k_ceil * Ft(x, j_ceil, k_ceil, t);
end
And now you want the fitness value at some arbitrary point (xp,jp,kp,tp):
fitness = interFt(@Ft,xp,jp,kp,tp)
That's all.
You don't need
fitness = interFt(@(x,j,k,t) Ft(x,j,k,t),xp,jp,kp,tp)
if your fitness function Ft should be called with the usual order of the input arguments (and this is the case in function interFt because Ft is always called as Ft(xp,some j, some k, tp)).
The only question that remains is:
Why do you overwrite state1 again and again in your 4-fold loop?
