function [fitresult, gof] = createFit(x, y)

[xData, yData] = prepareCurveData( x, y );

% Set up fittype and options.
ft = fittype( 'a-b*exp(x)', 'independent', 'x', 'dependent', 'y' );
opts = fitoptions( 'Method', 'NonlinearLeastSquares' );
opts.Display = 'off';
% opts.StartPoint = [0.867276403277854 0.0574539084707549];

% Fit model to data.
[fitresult, gof] = fit( xData, yData, ft, opts );

% Create a figure for the plots.
figure( 'Name', 'untitled fit 1' );

% Plot fit with data.
subplot( 2, 1, 1 );
h = plot( fitresult, xData, yData );
legend( h, 'y vs. x', 'untitled fit 1', 'Location', 'NorthEast' );
% Label axes
xlabel x
ylabel y
grid on

% Plot residuals.
subplot( 2, 1, 2 );
h = plot( fitresult, xData, yData, 'residuals' );
legend( h, 'untitled fit 1 - residuals', 'Zero Line', 'Location', 'NorthEast' );
% Label axes
xlabel x
ylabel y
grid on

2楼: Originally posted by 独孤神宇 at 2015-07-15 19:48:46
用cftool工具箱 拟合就是了 界面操作 简单快捷