Unable to perform assignment because the indices on the left side are not compatible with the size of the right side

When I run this code I get the above warning. Can someone see what I am doing wrong?

%% Optimizer (SPSA method)
n = 100;
theta = hourly_rating;
thetamin = hourly_rating ./ hourly_rating;
thetamax = hourly_rating .* 1.1;
alpha = 0.602 ;
gamma = 0.101 ;
a = 0.75;
c = 0.1;
A = 100;
p = numel(theta);

for k=0:n-1
    
    ak=a/(k+1+A)^alpha;
    ck=c/(k+1)^gamma;
    delta=2*round(rand(p,1))-1; %Fixme: How to determine delta
    
    for j=1:size(ws,2)
        current_year = strcat('y_',num2str((start_year +j)));
    
        for i=1:size(year.(current_year),1)
            thetaplus(i,j) = theta(i,j) + ck*delta;
            thetaminus(i,j) = theta(i,j) - ck*delta;
        end
    end
    
    yplus=objective_func(thetaplus,ws,app,input,start_year,year,eprice);
    yminus=objective_func(thetaminus,ws,app,input,start_year,year,eprice);
    ghat=(yplus-yminus)./(2*ck*delta);
    
    for j=1:size(ws,2)
        current_year = strcat('y_',num2str((start_year +j)));
    
        for i=1:size(year.(current_year),1)
            theta(i,j) = theta(i,j) - ak*ghat;
        end
    end
    
%     theta=min(theta,thetamax); %Fixme: where to implement this?
%     theta=max(theta,thetamin); %Fixme: idem?
    
end

[Srivardhan Gadila]

@Sietse van den Elzen, can you provide details on which line you are getting the error, values of variables like hourly_rating, ws etc and the code of the function objective_func