[move] add standard math library #3172
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movekevin
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Aug 21, 2022
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| /// Return the average of two. | ||
| public fun average(a: u64, b: u64): u64 { | ||
| (a & b) + (a ^ b) / 2 |
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I wonder if we really need the gas optimization here vs just doing (a + b) / 2
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Especially as a ^ b can overflow
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I think a + b has the overflow risk other than the original solution.
let's do (a & b) + (a ^ b) >> 1 using bit ops for the whole expression.
wrwg
reviewed
Aug 21, 2022
| module aptos_std::math { | ||
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| /// Return the largest of two numbers. | ||
| public fun max(a: u64, b: u64): u64 { |
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What about u128? And even if you don't introduce now, perhaps call these here max_u64 et. al?
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Alternatively, we can also put this into the module name, as in math64::max et. al
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I love the way to split the file into the two
movekevin
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Aug 30, 2022
lightmark
reviewed
Sep 2, 2022
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| p = p * p; | ||
| if (e % 2 == 1) { | ||
| p = p * n; | ||
| p | ||
| } else { | ||
| p | ||
| } |
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Suggested change
| p = p * p; | |
| if (e % 2 == 1) { | |
| p = p * n; | |
| p | |
| } else { | |
| p | |
| } | |
| if (e % 2 == 1) { | |
| p * p * n | |
| } else { | |
| p * p | |
| } |
I wonder which saves more gas?
lightmark
requested changes
Sep 2, 2022
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Synced with @movekevin please fix the average function. Sorry for the inconvenience.
lightmark
approved these changes
Sep 2, 2022
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gonna land it for now. I'll fix it later. |
davidiw
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Description
Adds a math standard library. There are currently four functions; max, min, average, and pow. These will be helpful, especially for DeFi builders on Aptos Network to calculate something.
Test Plan
In the file
math.move.This change is