clear all; close all;
load linefit.dat
x=linefit(:,1);
y=linefit(:,2);
plot(x,y,'O:')

xp=0:0.1:7;
clin=polyfit(x,y,1);
yp=polyval(clin,xp);
clin2=polyfit(x,y,2);
yp2=polyval(clin2,xp);

figure(2), plot(x,y,'O', ...
    xp,yp,'m',xp,yp2,'g')

n=length(x)-1;
clinn=polyfit(x,y,n);
ypn=polyval(clinn,xp);
figure(3), plot(x,y,'O',xp,ypn,'m')

yint=interp1(x,y,xp);
yspline=spline(x,y,xp);
figure(4), plot(x,y,'O',...
    xp,yint,'m',xp,yspline,'k')

load gaussfit.dat
x2=gaussfit(:,1)
y2=gaussfit(:,2)
figure(5), plot(x2,y2,'O:')

xga=-3:0.1:3;
coeff=fmins('gafit',[1 1]);
a=coeff(1); b=coeff(2)
yga=a*exp(-b*xga.^2);
figure(6), plot(x2,y2,'O',xga,yga,'m')