hi i have one query image and 20 dataset images and i want to find out the precision and recall graph but i am not getting the correct results pls help!!!

clc 
clear all

I=imread('1.jpg');                    % to read the image
I_read=imresize(I,[256 256]);
      % image resize
I=rgb2gray(I_);                      % rgb to gray conversion
%I=I_enlarge;
imshow(I);

Seq=cell(1,20);

for i=1:20

    I=imread(sprintf('%d.jpg',i));
     I=imresize(I,[256 256]);

     I=rgb2gray(I);
      Seq{i}=I;
end
for i = 1 : 20 % loop for calculating histogram intersections
    A=Seq{i};
    B=I;
    a = size(A,2); 
    b = size(B,2); 
    K = zeros(a, b);
    for j = 1:a
        Va = repmat(A(:,j),1,b);
        K(j,:) = 0.5*sum(Va + B - abs(Va - B));
    end  
end
num_images = 20;
sims=K
relevant_IDs = [1 2 3 4 5 6 7 8 9 10];
num_relevant_images = numel(relevant_IDs);
[sorted_sims, locs] = sort(sims, 'descend');

locations_final = arrayfun(@(x) find(locs == x, 1), relevant_IDs)
locations_sorted = sort(locations_final)
precision = (1:num_relevant_images) ./ locations_sorted;

recall = (1:num_relevant_images) / num_relevant_images;
disp(precision)
disp(recall)
plot(recall, precision, 'b.-');
xlabel('Recall');
ylabel('Precision');
title('Precision-Recall Graph - GEOGRAPHICAL IMAGE RETIREVAL');
axis([0 1 0 1.05]); %// Adjust axes for better viewing
grid;