% [discr, trueSolution] =  schemeFactory(m)
%     where trueSolution should be a timeSnapshot of the true solution a time T
% T is the end time
% m are grid size parameters.
% N are number of timesteps to use for each gird size
% timeOpt are options for the timeStepper
function e = calculateErrors(schemeFactory, T, m, N, errorFun, timeOpt)
    assertType(schemeFactory, 'function_handle');
    assertNumberOfArguments(schemeFactory, 1);
    assertScalar(T);
    assert(length(m) == length(N), 'Vectors m and N must have the same length');
    assertType(errorFun, 'function_handle');
    assertNumberOfArguments(errorFun, 2);
    default_arg('timeOpt');

    e = [];
    for i = 1:length(m)
        done = timeTask('m = %3d ', m(i));

        [discr, trueSolution] = schemeFactory(m(i));

        timeOpt.k = T/N(i);
        ts = discr.getTimestepper(timeOpt);
        ts.stepTo(N(i), true);
        approxSolution = discr.getTimeSnapshot(ts);

        e(i) = errorFun(trueSolution, approxSolution);

        fprintf('e = %.4e', e(i))
        done()
    end
    fprintf('\n')
end


%% Example error function
% u_true = grid.evalOn(dr.grid, @(x,y)trueSolution(T,x,y));
% err = u_true-u_false;
% e(i) = norm(err)/norm(u_true);
% % e(i) = sqrt(err'*d.H*d.J*err/(u_true'*d.H*d.J*u_true));