非线性最小二乘拟合问题
请问非线性最小二乘拟合编程,我好像求就是求不出来，请各位高手帮忙function y=myfun(abc,t)
y=abc(1)/(1+abc(2)*exp(-abc(3)*t))^(1/abc(4));
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%主程序如下
t=;
y=;
=lsqcurvefit('zhidao_aacceedd123',ones(1,4),t,y);
L=A(1)
u=A(2)
b=A(3)
fi=A(4)
%%%%%%%%%%%%%%%%%%
运行后，显示如下：
??? Error using ==> optim\private\lsqncommon
User supplied function failed with the following error:
Attempted to access abc(3); index out of bounds because numel(abc)=2.
Error in ==> lsqcurvefit at 149
= ...
Error in ==> Untitled2 at 3
=lsqcurvefit('myfun',ones(1,2),t,y);
%%%%%%%%%
不知道什么意思，还请各位高手帮忙看看啊 运行后怎么不是LZ显示的提示？
我电脑上提示是：
??? Error using ==> mpower
Matrix must be square.
Error in ==> myfun at 2
y=x(1)/(1+x(2)*exp(x(3)*xdata))^x(4);
Error in ==> lsqcurvefit at 209
initVals.F = feval(funfcn_x_xdata{3},xCurrent,XDATA,varargin{:});
Caused by:
Failure in initial user-supplied objective function evaluation. LSQCURVEFIT
cannot continue.
原因是 ^运算引起的，若矩阵A^B，A必须是方阵，这个例子不涉及到上面的情况，我把fun都改成点运算，结果如下：
xdata=;
ydata=;
x0=ones(4,1);
= lsqcurvefit(@myfun,x0,xdata,ydata)
Maximum number of function evaluations exceeded;
increase options.MaxFunEvals
x =
2.4575
0.0073
0.5028
36.6275
resnorm =
0.5454
M文件如下：
function y=myfun(x,xdata)
y=x(1)./(1+x(2).*exp(x(3).*xdata)).^x(4);
页:
[1]