zlacker

[return to "For algorithms, a little memory outweighs a lot of time"]
1. whatev+ti[view] [source] 2025-05-21 21:31:16
>>makira+(OP)
Lookup tables with precalculated things for the win!

In fact I don’t think we would need processors anymore if we were centrally storing all of the operations ever done in our processors.

Now fast retrieval is another problem for another thread.

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2. crmd+Jz[view] [source] 2025-05-22 00:23:09
>>whatev+ti
Reminds me of when I started working on storage systems as a young man and once suggested pre-computing every 4KB block once and just using pointers to the correct block as data is written, until someone pointed out that the number of unique 4KB blocks (2^32768) far exceeds the number of atoms in the universe.
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3. jodrel+DJ[view] [source] 2025-05-22 02:22:43
>>crmd+Jz
Reminds me of when I imagined brute-forcing every possible small picture as simply 256 shades of gray for each pixel x (640 x 480 = 307200 pixels) = 78 million possible pictures.

Actually I don't have any intuition for why that's wrong, except that if we catenate the rows into one long row then the picture can be considered as a number 307200 digits long in base 256, and then I see that it could represent 256^307200 possible different values. Which is a lot: https://www.wolframalpha.com/input?i=256%5E307200

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4. danwil+zj1[view] [source] 2025-05-22 09:40:29
>>jodrel+DJ
Yeah I had a similar thought back in the 90s and made a program to iterate through all possible images at a fairly low res, I left it running while I was at school and got home after many hours to find it had hardly got past the first row of pixels! This was a huge eye-opener about how big a possibility-space digital images really exist in!
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5. mystif+td2[view] [source] 2025-05-22 16:47:01
>>danwil+zj1
I has the same idea when I first learned about programming as a teenager. I wonder how many young programmers have had this exact same train of thought?
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