具体的报错提示如下：

Local minimum possible.

lsqcurvefit stopped because the final change in the sum of squares relative to

its initial value is less than the default value of the function tolerance.

<stopping criteria details>

我的代码如下：

t=[1790:10:2000]';

x=[3.9,5.3,7.2,9.6,12.9,17.1,23.2,31.4,38.6,50.2,62.9,76.0,92.0,106.5,123.2,131.7,150.7,179.3,204.0,226.5,251.4,281.4]';

fun=@(cs,td)cs(1)./(1+(cs(1)/3.9-1)*exp(-cs(2)*(td-1790)));

cs=lsqcurvefit(fun,rand(2,1),t,x,zeros(2,1));