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The $5000 Compression Challenge (2001)

patrickcraig.co.uk

41–50 of 192 posts

Re: The $5000 Compression Challenge (2001)

#41

suppose the data were generated by a csprng with 256 bits of state. then in fact there are just slightly more than 256 bits of entropy there (prng state plus the length of the generated file). only, you'd have a snail's chance in hell of actually finding that seed

If he really wanted to make sure he kept the money, he could just use a hardware RNG. I don’t know how common they were in 2001 but you could probably even generate some practically unpredictable random numbers using radio noise.

Re: The $5000 Compression Challenge (2001)

#43
I didn’t quite get the method used to „compress“ the data from the article, maybe this rephrasing helps someone:

You basically split the file every time you encounter a specific character, and your compressor just combines all files it finds with the character you split by. If you split at every „X“ Char which might occur 1000 times in the file, the compressor only needs a small script which joins all files and puts an „X“ between them, which is less than 1000 bytes. The „trick“ is storing the location of the Xs you removed in the file sizes of the individual files.

Re: The $5000 Compression Challenge (2001)

#44
post #25
post #9

I wonder if it would have been possible to win the challenge legitimately? If a randomly-generated file happened to contain some redundancy through sheer chance, you could hand-craft a compressor to take advantage of it. This compressor would not work in general for random data, but it could work for this one particular case. It's a bet worth taking, because the payoff, 50:1 ($5,000 to $100), is pretty good. Play the…

Somewhere (discussed on HN) someone devised a "better-than-perfect" compressor. Most inputs get compressed (smaller than input), except for one input that does not. That one input is cryptographically impossible to find - or something along those lines. Unfortunately I can't find the article I'm describing here, maybe someone else can? It was a long time ago so I might be misrepresenting it slightly.

You could design the opposite, a system where ultra-rare files get compressed a lot but most don't compress.

But as stated, what you said is not possible. To compress by a single byte, only 1/256 files can be compressible, or you'd have multiple different inputs compressing down to the same output.

Re: The $5000 Compression Challenge (2001)

#45

Earlier quoted context omitted.

I have a fundamental problem with the Hutter prize stating that intelligence is related to compression & then sponsoring a prize for lossless compression. Intelligence is related to lossy compression. Lossless is mainly a mechanistic act.

Isn’t the intelligence shown by compressing lossless the scheme you use? Applying the algorithm is the easy part, the proof of intelligence is inventing the algorithm which compresses.

Hutter put up the prize as a way of getting people to approximate his AIXI algorithm, which he already considers to be the pinnacle of artificially intelligence. That's also why lossy compression isn't interesting. It'd be an approximation of an approximation and not particularly useful for hutter's purpose.

Re: The $5000 Compression Challenge (2001)

#46

The original email thread was from 2001, and it gets posted to HN periodically: https://news.ycombinator.com/from?site=patrickcraig.co.uk For another compression challenge that is still ongoing, try "500000€ Prize for Compressing Human Knowledge" (also known as "Hutter Prize"): http://prize.hutter1.net/ https://news.ycombinator.com/item?id=37502329 - Hutter Prize for compressing human knowledge (2023-09-13, 215 comme…

I have a fundamental problem with the Hutter prize stating that intelligence is related to compression & then sponsoring a prize for lossless compression. Intelligence is related to lossy compression. Lossless is mainly a mechanistic act.

Say we have some dataset composed of D bytes.

Next, say I find some predictive model of the data M, where M is composed of N bytes. Furthermore, let us say that the entropy of the dataset under the model is H bytes.

Then, if N + H It doesn't matter if the model is deterministic or probabilistic: a probabilistic model can be used to (losslessly) compress a dataset with entropy coding.

One more argument for compression being equivalent to intelligence: Across many fields of statistical machine learning, there are generalization bounds which have the form:

test error That is, we don't expect to do any worse on new (test) data, than the sum of the train error and the model complexity (smallest compressed size). Notice that if you interpret the train error as the entropy of the data (i.e. error under a cross entropy loss), then the models which satisfy the statistical generalization bound correspond to those which best compress the data. In other words: the model which produces the shortest description of the data is the one which is expected to generalize best.

Re: The $5000 Compression Challenge (2001)

#48

I would not have accepted multiple files nor scripting. Scripts offers up the entire contents of the linux operating system and this could allow you to use operating system files as partial data. To really test compression/decompression the rules need to be a lot tighter. The challenge was met and beat because the criteria was bad. It leaves open a number of dishonest approaches. The decompression program needs to be…

> Scripts offers up the entire contents of the linux operating system and this could allow you to use operating system files as partial data. I also thought about this, but when thinking more about the argument by the challenge creator, I understood that the data in the OS doesn’t help you. If you’re given a file with 100 bits, there are 2^100 possibilities. If you want to compress to 99 bits, there are only 2^99 pos…

My decompressor:

curl ftp://path/to/original.dat

Re: The $5000 Compression Challenge (2001)

#49
post #46

Earlier quoted context omitted.

I have a fundamental problem with the Hutter prize stating that intelligence is related to compression & then sponsoring a prize for lossless compression. Intelligence is related to lossy compression. Lossless is mainly a mechanistic act.

Say we have some dataset composed of D bytes. Next, say I find some predictive model of the data M, where M is composed of N bytes. Furthermore, let us say that the entropy of the dataset under the model is H bytes. Then, if N + H It doesn't matter if the model is deterministic or probabilistic: a probabilistic model can be used to (losslessly) compress a dataset with entropy coding. One more argument for compression…

This seems to assume that there is a tractable way to encode H efficiently, but this seems very difficult given a model that is focused on understanding the content. Ex: I can easily write a program that can do basic arithmetic, but given say a bitmap scan of elementary school math materials, such a program gives me no easy way to compress that; rather something generic like PNG (that does not know or understand the material) will far outperform.

Re: The $5000 Compression Challenge (2001)

#50

This guy clearly failed because he didn't actually do any compression, he just ab-used the filesystem to store parts of the data and then tried to argue that metadata was not data... But FYI someone else actually managed to compress that exact same data: https://jasp.net/tjnn/2018/1.xhtml

He clearly failed at doing any actual compression, but he did not fail at the challenge. He satisfied every single condition.

He obviously knows that. He knows exactly what compression is and that his solution is not it. He showed (successfully) that meeting the challenge as it was worded did not require compression, which the setter of the challenge didn't realize.

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