close all;
t= [ 11.9270   15.7330  20.9000  60.0360 
  13.7500   13.5700  20.5990  98.2420
  13.3890   13.2690  20.9200  40.3280
  14.1800   13.5000  20.8700  88.7380
  12.7180   13.3990  20.9600  44.3140
  14.2700   13.2990  20.8800  96.3290
  11.9570   13.3890  22.1920  89.1880
  12.5480   13.5900  20.6290  81.3870];
t1=mean(t(1:8)),t2=mean(t(9:16)),t3=mean(t(17:24)),t4=mean(t(25:32)),
w=[2 3 4 6 8 12 16];w0=[2 4 8 16];
p0=[t4 t3 t2 t1];
p=[t4 (t3+t4)/2 t3 (t3+t2)/2 t2 (t2+t1)/2 t1];
plot(w0,p0,'r*');hold on;

% x=w;y=p;
% [a,s]=polyfit(x,y,4);a
% i=0.5:0.1:18;
% %p1=a(1)*i.^3+a(2)*i.^2+a(3)*i+a(4);
% p1=a(1)*i.^4+a(2)*i.^3+a(3)*i.^2+a(4)*i+a(5);
% plot(i,p1,'LineWidth',1.8)


x=[2 4 8 16];y=p0;
a0=[-1 1 -1];
options=optimset('fminsearch');
options.TolX=0.005;
options.Display='off';
a=fminsearch(@logg,a0,options,x,y);
a
i=1:0.1:3;
p1=-a(1).*log(a(2).*i)./i+a(3);
% plot(i,p1)
plot(i,p1,'LineWidth',1.8);
axis([1 32 0 max(p1)])