I saw this project on github https://github.com/philipl/pifs, where they are trying to compress files in the pi number after the decimal. I guess this makes sense because apparently every finite sequence of digits exist in the never ending decimal numbers of pi. But I am trying to understand 1 step of their process.
So firstly from what I understand, if you want to compress a file, that is really represented in a sequence of numbers like say 471947...2846 (somehow gotten from base 16). Then, they assume that sequence is somewhere in pi.
They somehow then look up where the sequence starts in pi. This is the step I don't understand how they do. But they use a formula called Bailey–Borwein–Plouffe formula to do it.
So the compression is really two numbers $<A,B>$, where A is the index of the start number of pi, and B is the length needed.
To uncompress, its just a for loop, loop through every index from A, and repeat B times, and use that formula, to get the pi digit value, then convert it back to binary, and you have the original file again.
But it's that first step to find that initial start index using the formula I don't understand how that's done. Surely they don't brute force and try every combination in a linear fashion.
Does anyone know?