当尝试安装syms W1
syms W2
format long
format compact
data = xlsread('sample8.xlsx'); % two columns of data
xdata = data(:,1);
ydata = data(:,2);
Area = 133; % area of surface mm^2
Force = ydata; %mN
L = 1 - (xdata ./ 100); %Lambda
Lambda_inverse = L.^-1;
F = blkdiag(L.^-1, L.^-1, L.^2);
FT = F.';
B = F*FT;
I1 = trace(B);
fun = @(W,xdata) -Area.*( (W(1).* exp( (W(2)) .* (I1 - 3)) ) .* (L.^2 .* L.^-1) );
%starting guess
Wguess = [5,5];
[W,fminres] = lsqcurvefit(fun,Wguess,xdata,ydata)
软件包时，我在RStudio中收到此消息：
有想法吗？
非常感谢。
shotext