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: rankest.m
    path of file: ./repos/imtsl/libs/tensorlab
    
    the code of the file until where you have to start completion: function [R,L_lb,L_cpd] = rankest(T,options)
%RANKEST Estimate rank.
%   rankest(T) plots an L-curve of number of rank-one terms in a canonical
%   polyadic decomposition. The x-axis corresponds to the number of
%   rank-one terms, and the y-axis corresponds to the relative error of the
%   CPD in that many rank-one terms. Additionally, the corner R of the
%   resulting L-curve is estimated.
%
%   R = rankest(T) doe
    
function Lcurve(update)
    if R(r) <= 1, return; end
    style = {'Marker','+','MarkerSize',2.5};
    if ~update
        semilogy(R(opt),relerr(opt),'rs','LineStyle','none'); hold on;
    end
    semilogy(R(1:length(relerr)),relerr,'r',style{:}); hold on;
    semilogy(1:length(lb),lb,style{:});
    semilogy([1 R(r)],options.MinRelErr*[1 1],'k:');
    text(1,options.MinRelErr,'MinRelErr','VerticalAlignment','Top');
    hold off;
    ylim([min(options.MinRelErr/(10^0.5),min(relerr(1:r))) lb(1)]);
    xlim([1 R(r)]);
    ylabel('frob(cpdres(T,U))/frob(T)'); xlabel('R');
    xt = get(gca,'XTick'); set(gca,'XTick',xt(mod(xt,1) == 0));
    if update
        if ~isempty(lb)
            legend