You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: recall_precision.m
    path of file: ./repos/hashing-baseline-for-image-retrieval/Method-SELVE
    
    the code of the file until where you have to start completion: function [recall, precision, rate] = recall_precision(Wtrue, Dhat,  max_hamm)
%
% Input:
%    Wtrue = true neighbors [Ntest * Ndataset], can be a full matrix NxN
%    Dhat  = estimated distances
%
% Output:
%
%                  exp. # of good pairs inside hamming ball of radius <= (n-1)

    
function [recall, precision, rate] = recall_precision(Wtrue, Dhat,  max_hamm)
%
% Input:
%    Wtrue = true neighbors [Ntest * Ndataset], can be a full matrix NxN
%    Dhat  = estimated distances
%
% Output:
%
%                  exp. # of good pairs inside hamming ball of radius <= (n-1)
%  precision(n) = --------------------------------------------------------------
%                  exp. # of total pairs inside hamming ball of radius <= (n-1)
%
%               exp. # of good pairs inside hamming ball of radius <= (n-1)
%  recall(n) = --------------------------------------------------------------
%                          exp. # of total good pairs 

if(nargin < 3)
    max_hamm = max(Dhat(:));
end