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: tracker.m
    path of file: ./repos/siamese-fc/tracking
    
    the code of the file until where you have to start completion: % -------------------------------------------------------------------------------------------------
function bboxes = tracker(varargin)
%TRACKER
%   is the main function that performs the tracking loop
%   Default parameters are overwritten by VARARGIN
%
%   Luca Bertinetto, Jack Valmadre, Joao F. Henriques, 2016
% -------------------------------------------------------------------------------------------------
    % These are the default hyper-params for SiamFC-3S
    % The ones for SiamFC (5 scales) are in params-5s.txt
    p.numScale = 3;
    p.scaleStep = 1.0375;
    p.scalePenalty = 0.9745;
    p.scaleLR = 0.59; % damping factor for scale update
    p.responseUp = 16; % upsampling the small 17x17 response helps with the accuracy
    p.windowing = 'cosine'; % to penalize large displacements
    p.wInfluence = 0.176; % windowing influence (in convex sum)
    p.net = '2016-08-17.net.mat';
    %% execution, visualization, benchmark
    p.video = 'vot15_bag';
    p.visualization = false;
    p.gpus = 1;
    p.bbox_output = false;
    p.fout = -1;
    %% Params from the network architecture, have to be consistent with the training
    p.exemplarSize = 127;  % input z size
    p.instanceSize = 255;  % input x size (search region)
    p.scoreSize = 17;
    p.totalStride = 8;
    p.contextAmount = 0.5; % context amount for the exemplar
    p.subMean = false;
    %% SiamFC prefix and ids
    p.prefix_z = 'a_'; % used to ident
    
function bboxes = tracker(varargin)
%TRACKER
%   is the main function that performs the tracking loop
%   Default parameters are overwritten by VARARGIN
%
%   Luca Bertinetto, Jack Valmadre, Joao F. Henriques, 2016
% -------------------------------------------------------------------------------------------------
    % These are the default hyper-params for SiamFC-3S
    % The ones for SiamFC (5 scales) are in params-5s.txt
    p.numScale = 3;
    p.scaleStep = 1.0375;
    p.scalePenalty = 0.9745;
    p.scaleLR = 0.59; % damping factor for scale update
    p.responseUp = 16; % upsampling the small 17x17 response helps with the accuracy
    p.windowing = 'cosine'; % to penalize large displacements
    p.wInfluence = 0.176; % windowing influence (in convex sum)
    p.net = '2016-08-17.net.mat';
    %% execution, visualization, benchmark
    p.video = 'vot15_bag';
    p.visualization = false;
    p.gpus = 1;
    p.bbox_output = false;
    p.fout = -1;
    %% Params from the network architecture, have to be consistent with the training
    p.exemplarSize = 127;  % input z size
    p.instanceSize = 255;  % input x size (search region)
    p.scoreSize = 17;
    p.totalStride = 8;
    p.contextAmount = 0.5; % context amount for the exemplar
    p.subMean = false;
    %% SiamFC prefix and ids
    p.prefix_z = 'a_'; % used to identify the layers of the exemplar
    p.prefix_x = 'b_'; % used to identify the layers of the instance
    p.prefix_join = 'xcorr';
    p.prefix_adj = 'adjust';
    p.id_feat_z = 'a_feat';
    p.id_score = 'score';
    % Overwrite default parameters with varargin
    p = vl_argparse(p, varargin);
% -------------------------------------------------------------------------------------------------

    % Get environment-specific default paths.
    p = env_paths_tracking(p);
    % Load ImageNet Video statistics
    if exist(p.stats_path,'file')
        stats = load(p.stats_path);
    else
        warning('No stats found at %s', p.stats_path);
        stats = [];
    end