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4 billion if statements (2023)

andreasjhkarlsson.github.io

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Re: 4 billion if statements (2023)

#91

Post by xnorswap »

This is time efficient* but rather wasteful of space.

The best way to save space is to use a Bloom Filter.

If we capture all the even numbers, that would sadly only give us "Definitely not Even" or "Maybe Even".

But for just the cost of doubling our space, we can use two Bloom filters!

So we can construct one bloom filter capturing even numbers, and another bloom filter capturing odd numbers.

Now we have "Definitely not Even" and "Maybe Even" but also "Definitely not Odd" and "Maybe Odd".

In this manner, we can use the "evens" filter to find the odd numbers and the "odds" filter to find the even numbers.

Having done this, we'll be left with just a handful of unlucky numbers that are recorded as both "Maybe even" and "Maybe odd". These will surely be few enough in number that we can special case these in our if/else block.

The filters as a first-pass will save gigabytes of memory!

Re: 4 billion if statements (2023)

#92

Post by tkapin »

opticfluorine wrote: post #49
ZeroConcerns wrote: post #15

Ah, yes, exactly the pointless diversion I needed for my lunch break. For science: generating a C# switch statement for similar purposes took 7 minutes on similar-ish hardware, but the resulting 99.2GB file could not be opened or compiled ('Stream is too long'), which was slightly disappointing. Optimization efforts included increasing the internal buffer size of the StreamWriter used to create the source code: this…

I wonder if you could generate it via a Roslyn incremental source generator instead of as a file to bypass this limit. I'm guessing not, but it does sound like fun.

You can totally use source generators for that.

Re: 4 billion if statements (2023)

#94

Post by LPisGood »

travisgriggs wrote: post #89

I see this is 2023… the article refs GPT even then. Can’t believe it’s already that much time gone by, still seems like “last years big news” I was gonna comment “this is what I really like to see on HN”. Then I saw the date and was sad that we’re having to dip into the history box to find fun/interesting articles more often of late it seems. Anyone else interested in a temporary moratorium on all things LLM? We coul…

> Then I saw the date and was sad that we’re having to dip into the history box to find fun/interesting articles more often of late it seems

We don’t _have_ to. You could start a blog and display the indomitable human spirit.

Re: 4 billion if statements (2023)

#95

Post by virgilp »

travisgriggs wrote: post #89

I see this is 2023… the article refs GPT even then. Can’t believe it’s already that much time gone by, still seems like “last years big news” I was gonna comment “this is what I really like to see on HN”. Then I saw the date and was sad that we’re having to dip into the history box to find fun/interesting articles more often of late it seems. Anyone else interested in a temporary moratorium on all things LLM? We coul…

Definitely not a visionary. This is how you do it in 2025: https://imgur.com/rWiP90P

Re: 4 billion if statements (2023)

#96

Post by IncreasePosts »

majkinetor wrote: post #72
blauditore wrote: post #66

This could be obviously done with much less code: Just add "if"s for all even number, and at the end just return "odd" if none of the evens matched. 50% less code! Or even simpler: If it's 0, return "even". If not, do a recursive call to n-1, if that equals "even", return "odd", otherwise return "even". But the best way is probably to just use a library. Yes, 500MB of additional dependencies, but then it's a one-line…

But then, even numbers will have the worst possible performance.

Good point. Have two programs - one checking every even number and returning odd of not even. And then have a program checking every odd number and returning even if not. Then, a simple program to dispatch to either program randomly, so you end up in the long term with good performance for each.

Re: 4 billion if statements (2023)

#97

Post by DeathArrow »

klaff wrote: post #78
DeathArrow wrote: post #65

I would also like to praise the visionary genius Ross van der Gussom, without whom this wonderful achievement in software engineering would not have been possible!

Is he the one married to the singer, Adele Dazeem?

No, this one is the creator of the mighty programming language Mython.

Re: 4 billion if statements (2023)

#98

Post by nixpulvis »

xnorswap wrote: post #91

This is time efficient* but rather wasteful of space. The best way to save space is to use a Bloom Filter. If we capture all the even numbers, that would sadly only give us "Definitely not Even" or "Maybe Even". But for just the cost of doubling our space, we can use two Bloom filters! So we can construct one bloom filter capturing even numbers, and another bloom filter capturing odd numbers. Now we have "Definitely…

How is this time efficient at all? It takes upwards of 40 seconds to compute on large 32bit values.

It's a joke post with some interesting bits and details.

Re: 4 billion if statements (2023)

#99

Post by thedougd »

I took an ASIC design class in college, unfortunately with a heavy course load that didn't allow me to focus on it. For our final project we were given a numbered dictionary and asked to design a chip that would accept the characters on a 7 bit interface (ASCII), one character per clock cycle and output the dictionary number on an output interface but I can't remember how wide. We were graded on the size of the resulting ASIC and how many clock cycles it took from the last character in to the number on the output.

I started designing my modules, a ROM, a register with a ROM pointer, etc, etc, writing the Verilog and working out the clock sync between modules. Then I got 'lazy' and wrote a trie tree like implementation in Java, and have it spit out the whole tree in Verilog. It worked and just one clock cycle after the last letter my number would output. Fastest in the class! Also the most number of gates in the class. Surprised I got a 90 grade given I didn't use any of the advanced ASIC design the class taught. The TA didn't know what the hell they were looking at.

Re: 4 billion if statements (2023)

#100

Post by wiz21c »

classified wrote: post #57
wiz21c wrote: post #8

Gemini took 4 seconds to answer this prompt: "Here is a number 4200020010101. Think deeply about it and tell me if it is not or or not even." So if you're concerned with privacy issues, you can run the assembly version proposed in the article locally and be well within the same order of performance. Let's thank the author of the article for providing a decent alternative to Google. ah, but the license is not that goo…

> if it is not or or not even Did you want to test the LLM's grammatical comprehension?

When I'm tired my typing goes bad. I obvioulsy meant: "is that number even odd ?" :-)
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