%function [testPerf,rankmat,rank] = nnclassFn(train,test,trainClass,answer)
%
%Reads in training examples, test examples, class labels of training
%examples, and correct class of test examples. Data are in columns of train
%and test, and labels are column vectors.
% 
%Note: You will need to create label vectors. TrainClass is a column 
%vector of integers indicating the identity of the training examples. 
%e.g. for faces of 3 people with two views each, TrainClass = [1 1 2 2 3 3 ]';
%Answer contains the correct labels of the test images, which enables
%us to compute percent correct.  
%
%Gets matrix of normalized dot products. Outputs nearest neighbor
%classification of test examples and percent correct.
%rankmat gives the top 30 matches for each test image.  rank is a vector
%containing the percent of times the correct match is in the top N matches.


function [testPerf,rankmat,rank] = nnclassFn(train,test,trainClass,answer);

numTest = size(test,2);
numTrain = size(train,2);

%Get distances to training examples
%dists = eucDist(test,train); %Outputs a Ntest x Ntrain matrix of Euc dist
dists=-1 * cosFn(test,train);%Outputs a Ntest x Ntrain matrix of cosines

%sort the rows of dists to find the nearest training example:
[Sdist,nearest] = sort(dists'); %cols of Sdist are distances in ascend order
        %1st row of nearest is index of 1st closest training example

%Create vector with nearest example, and vector with class label.
Nnbr = nearest(1,:);            %First row of nearest contains NN
%Nnbr = nearest(2,:);
testClass = trainClass(Nnbr);

correct = find( (testClass - answer == 0));
testPerf = size(correct,1) / size(answer,1)
if(size(correct,2)>size(correct,1))
        testPerf = size(correct,2) / size(answer,2)
        'check vector orientation'
end

%get rank = %correct in top N:
cumtestPerf=0;
for i = 1:3
        rankmat(:,i) = trainClass(nearest(i,:)');
        correcti = find( (rankmat(:,i) - answer == 0));
        cumtestPerf = cumtestPerf + size(correcti,1) / size(answer,1);
        rank(i) = cumtestPerf;
end

%For FERET test, want probeID (answer), then rank, then matched ID no.,
%then FA flag, then "matching score".  This will be a matrix with: 
%probe  rank    match                           FAflag          matching score
%i      1       trainClass(nearest(i,:))        Sdist(:,i)>4.7  1./Sdist(:,i)
%i      2       OR rankmat(i,:)'
%i      3
%i      4