graphics_toolkit("gnuplot")
dados=load("temperatura.dat");
nx=size(dados,1);
x=dados(1:nx,2); j=1;
dx=x(2:nx,j)-x(1:nx-1,j);
figure, plot(x(1:96,1),"or-","markerfacecolor","r","linewidth",2)
grid on
title(["X   (Nx = " num2str(nx) ")"])
axis([0 96])
xmed(j)=mean(x(:,j))
xvar(j)=var(x(:,j))
x0=x;
x0(:,j)=x(:,j)-xmed(j);
nr=24*60,r=zeros(nr+1,length(j));
for i=0:nr 
r(i+1,j)=sum(x0(1:nx-i,j).*x0(i+1:nx,j))./xvar(j)/(nx-i-1); 
end
figure, plot([0:nr],r(:,1),"r-","markerfacecolor","r","linewidth",2)
title(["Func. autocorr. r   (Nx = " num2str(nx) ")"])
axis([0 nr])
dxmed(j)=mean(dx(:,j))
dxvar(j)=var(dx(:,j))
dx0=dx;
dx0(:,j)=dx(:,j)-dxmed(j);
nr=24*60,r=zeros(nr+1,length(j));
for i=0:nr 
dr(i+1,j)=sum(dx0(1:nx-1-i,j).*dx0(i+1:nx-1,j))./dxvar(j)/(nx-1-i-1); 
end
figure, plot([0:nr],dr(:,1),"r-","markerfacecolor","r","linewidth",2)
title(["Func. autocorr. de dx   (Nx = " num2str(nx) ,")"])
axis([0 nr])