As we know, there is at least one kind of such machines: the humankind.

]]>The algorithm can be coded in MATLAB as follows. Any irrational number can be used as the seed (the irrational unit length *ir* in this program). For example, I tried (*sqrt(2)*exp(1)* in MATLAB). You may make it in your own flavor.

中秋快乐！

%If the ratio of the periods of two periodic lattice is irrational, %they will never superimpose each other after the first point. Thus, %the decimal part of a 1D periodic lattice with the unit length of an %irrational number will not repeat as we probe unidirectionally along %the lattice. From another perspective, if we fold such a 1D lattice %into a 1D box of length 1, the lattice point will fill up the box %except for those rational fraction points. This can be used to %create pseudo random numbers between 0 and 1. %Initially, we get the decimal part of an irrational number as the first %number in the random series, use its last digit (semi-random due to the %roundoff error) to jump to the next lattice point. %Here we use pi as the irrational period of the lattice. We can use %other irrational number function [] = RandomFraction(p,n,ir) %p: the precision of the output numbers %n: the number of iteration %ir: the irrational unit length, e.g. pi, exp(1), sqrt(2), etc. r = 0; %Vector of advancing c = 0; %Jumping number for i = 1 : n r = r + (c + 1) * ir; %Use c+1 to avoid stopping at c=0 x = r - floor(r); %Get decimal part s = sprintf('%.*f',p,x) %Show decimal part and transfer to string c = sscanf(s(p + 2),'%d'); %Get the last digit of decimal part end

Here I simply test the seed at different iterations.

Well, my old computer starts to complain. Although double precision allows more than iterations, I would not push that hard.