| ▲ | adzm 6 hours ago |
| It is worth noting that as the length of data increases it becomes extremely unlikely that the index and length of the sequence within pi would actually be smaller than the data. |
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| ▲ | Aloisius 6 hours ago | parent | next [-] |
| That seems easy enough to solve. Simply record the index and length in pi of the index and length in pi. |
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| ▲ | jastr 3 hours ago | parent | prev | next [-] |
| Back in college, I thought I could compress my phone number by telling people its index in pi, but my 7 digit phone number is at an 8 digit index. I didn’t have the compute to find my 10 digit number with the area code. |
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| ▲ | mondrian 5 hours ago | parent | prev | next [-] |
| The index of your 20 line file is <20TB number> |
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| ▲ | russfink 4 hours ago | parent [-] | | Unless, in turn, you locate the index itself in pi at a much smaller index. And so on... Find k candidate indices for your data, then locate each of them. If the smallest one is a significantly smaller index space, repeat. | | |
| ▲ | akoboldfrying 3 hours ago | parent [-] | | Can't tell if you're in on the joke or not, but for anyone who is genuinely wondering whether this might work: Consider that there are at most 256 different indexes that could be represented by a 1-byte index value, but if you're trying to store 9 bits of data, there are already 512 different possible things it could be that each need to be represented by a different index value, otherwise you won't be able to tell them apart. Those pigeons aren't gonna fit. |
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| ▲ | 12_throw_away 6 hours ago | parent | prev | next [-] |
| yes I believe that's the joke |
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| ▲ | liamYC 4 hours ago | parent | prev | next [-] |
| Point taken about the index potentially being really long. Why would the length be longer than the data? Don’t you need to find the right sequence? |
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| ▲ | gowld 2 hours ago | parent [-] | | For a given length of data, considering all possible data of that length, it's impossible for the median length to be shorter than the data length. There aren't enough strings of that length that early in the data. |
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| ▲ | hatthew 4 hours ago | parent | prev [-] |
| TFA addresses this > Now, we all know that it can take a while to find a long sequence of digits in π, so for practical reasons, we should break the files up into smaller chunks that can be more readily found. > In this implementation, to maximise performance, we consider each individual byte of the file separately, and look it up in π. |
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| ▲ | ithkuil 3 hours ago | parent [-] | | Why stop at bytes? Let's split it in individual bits and then look up the bits in pi! But Pi's binary expansion is not very practical for this purpose, since it's 11.0010... OTOH. e is 10.1011... Let's stick to fractional digits (the ones right of the binary point) at index 0 we have 1 and at index 1 we have 0. So, to encode a stream of bytes so that each bit is encoded as the index of that bit in the e, all you need to do is to xor it with 0xFF | | |
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