%l1_s分别是不同实验条件下的数据，下面的函数为极大既然函数的负值，先用fmincon求解，运行出错了。

function [l1_s,l2_s,l3_s,l4_s,l5_s,l6_s] = readandevaluate(filename)

global l1_s l2_s l3_s l4_s l5_s l6_s;

filename = 'li_s.xlsx';

l1_s = xlsread(filename,'A:A');

l2_s = xlsread(filename,'B:B');

l3_s = xlsread(filename,'C:C');

l4_s = xlsread(filename,'D

');

l5_s = xlsread(filename,'E:E');

l6_s = xlsread(filename,'F:F');

end

function f = fmin4mle(x)

global l1_s l2_s l3_s l4_s l5_s l6_s;

f = -(x(5)*l1_s.^(x(5)-1)*exp(-x(5)*(x(1)+x(2)/80+x(3)/20+x(4)*log(20)))*exp(-l1_s.^x(5)*exp(-x(5)*(x(1)+x(2)/80+x(3)/80+x(4)*log(20)))))...

*(x(5)*l2_s.^(x(5)-1)*exp(-x(5)*(x(1)+x(2)/80+x(3)/60+x(4)*log(20)))*exp(-l2_s.^x(5)*exp(-x(5)*(x(1)+x(2)/80+x(3)/80+x(4)*log(60)))))...

*(x(5)*l3_s.^(x(5)-1)*exp(-x(5)*(x(1)+x(2)/80+x(3)/40+x(4)*log(20)))*exp(-l3_s.^x(5)*exp(-x(5)*(x(1)+x(2)/55+x(3)/80+x(4)*log(40)))))...

*(x(5)*l4_s.^(x(5)-1)*exp(-x(5)*(x(1)+x(2)/95+x(3)/20+x(4)*log(20)))*exp(-l4_s.^x(5)*exp(-x(5)*(x(1)+x(2)/55+x(3)/95+x(4)*log(20)))))...

*(x(5)*l5_s.^(x(5)-1)*exp(-x(5)*(x(1)+x(2)/95+x(3)/60+x(4)*log(20)))*exp(-l5_s.^x(5)*exp(-x(5)*(x(1)+x(2)/70+x(3)/95+x(4)*log(60)))))...

*(x(5)*l6_s.^(x(5)-1)*exp(-x(5)*(x(1)+x(2)/95+x(3)/40+x(4)*log(20)))*exp(-l6_s.^x(5)*exp(-x(5)*(x(1)+x(2)/70+x(3)/95+x(4)*log(40)))));

end

A = [0 0 0 0 -1];

b = [0];

x0 = [10,10,10,10,10];

[x,fval] = fmincon(@readandevaluate,x0,A,b)

提示错误如下：

错误使用 fmincon (line 637)

User supplied objective function must return a scalar value.