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: eval.m
    path of file: ./repos/face_verification_experiment/code/+evaluation/+roc
    
    the code of the file until where you have to start completion: %  Copyright (c) 2014, Karen Simonyan
%  All rights reserved.
%  This code is made availabl
    
function [res, extra] = eval(config, scores, gt)
    
    [~,~,info] = vl_roc(gt, scores);
    
    % the accuracy at the ROC operating point where the error rates are equal (as in [Guillaumin et al., ICCV '09])
    res = (1 - info.eer) * 100;
    extra = info;
end