MATLAB: Findpeaks in for loop; find maximum’s corresponding x value

Question

Hi, I want to find in each loop for L, the maximum value of SP and corresponding p value. That means, I want the results to be two vectors of length numel(L).

I know that findpeaks could help to identify the maximum and its location, but i always got the error message "In an assignment A(:) = B, the number of elements in A and B must be the same. Error in optimalp(j) = prange(locs);"

Could anyone help me to fix this? Or is there any other methods to output the maximum of SP and corresponding p values? Because i want to use the vectors to plot the graph later.

THANKS!!!

L = 0.01:0.01:1;
p = 0:0.01:1; 
optimalp = zeros(1,numel(L));
maximum = zeros(1,numel(L));
SP = zeros(1,numel(p));
for j = 1:numel(L)
      for i = 1:numel(p)
          if Lambda(j) >= mu
              if p(i) < R-c^2/(mu*phi)
                  SP(i) = p(i)*(mu-c/(R-p(i)));
              else
                  SP(i) = p(i)*(mu-sqrt(mu*phi/(R-p(i))));
              end        
          else
              SP(i) = p(i)*L(j);
          end
      end
      [pks,locs]=findpeaks(SP);
      optimalp(j) = p(locs);
  end

Answer 1

findpeaks returns all the peaks it finds by default. if you just want the largest one you can change your call to:

[~, lochighest] = findpeaks(SP, 'SortStr', 'descend', 'NPeaks', 1);
optimal(j) = p(lochighest);