j = 1;
for i=-10:0.001:10
    if((i>=0)&&(i<=1))
        y(j) = sqrt(i);
    else
        y(j) = 0;
    end
    j = j + 1;
end
i=-10:0.001:10;
y_conv = ifft(y.*y);
plot(i,y_conv);