程序命令如下，但总是出错，请高手指教，是哪里出了错误，附件为命令的txt格式，谢谢！

>> f=@(a,x) (1/((2*pi)^0.5*a(1)*x))*exp(-1/2*(log(x)-a(2))^2/a(1)^2);
x=1:0.5:19;
y=[3.155 8.621 11.777 9.170 17.110 18.813 22.961 24.887 25.331 22.961 20.739 18.517 15.702 12.888 10.666 9.184 7.999 6.814 6.370 5.481 5.185 5.037...
4.740 4.148 4.000 3.851 3.881 3.881 3.807 3.985 3.881 3.614 3.244 3.526 2.977 3.348 3.348];
a0=[4.4013 7.4999];
a=lsqcurvefit(f,a0,x,y);
??? Error using ==> mldivide
Matrix dimensions must agree.
Error in ==> @(a,x)(1/((2*pi)^0.5*a(1)*x))*exp(-1/2*(log(x)-a(2))^2/a(1)^2)

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.