mirror of
https://github.com/0glabs/0g-chain.git
synced 2024-11-14 03:55:19 +00:00
82 lines
2.2 KiB
Go
82 lines
2.2 KiB
Go
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package keeper
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import (
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"sort"
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sdk "github.com/cosmos/cosmos-sdk/types"
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)
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// splitIntIntoWeightedBuckets divides an initial +ve integer among several buckets in proportion to the buckets' weights
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// It uses the largest remainder method: https://en.wikipedia.org/wiki/Largest_remainder_method
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// See also: https://stackoverflow.com/questions/13483430/how-to-make-rounded-percentages-add-up-to-100
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// note - copied from auction, tests are located there.
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func splitIntIntoWeightedBuckets(amount sdk.Int, buckets []sdk.Int) []sdk.Int {
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// Limit input to +ve numbers as algorithm hasn't been scoped to work with -ve numbers.
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if amount.IsNegative() {
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panic("negative amount")
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}
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if len(buckets) < 1 {
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panic("no buckets")
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}
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for _, bucket := range buckets {
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if bucket.IsNegative() {
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panic("negative bucket")
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}
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}
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// 1) Split the amount by weights, recording whole number part and remainder
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totalWeights := totalInts(buckets...)
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if !totalWeights.IsPositive() {
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panic("total weights must sum to > 0")
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}
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quotients := make([]quoRem, len(buckets))
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for i := range buckets {
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// amount * ( weight/total_weight )
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q := amount.Mul(buckets[i]).Quo(totalWeights)
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r := amount.Mul(buckets[i]).Mod(totalWeights)
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quotients[i] = quoRem{index: i, quo: q, rem: r}
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}
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// 2) Calculate total left over from remainders, and apportion it to buckets with the highest remainder (to minimize error)
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// sort by decreasing remainder order
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sort.Slice(quotients, func(i, j int) bool {
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return quotients[i].rem.GT(quotients[j].rem)
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})
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// calculate total left over from remainders
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allocated := sdk.ZeroInt()
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for _, qr := range quotients {
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allocated = allocated.Add(qr.quo)
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}
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leftToAllocate := amount.Sub(allocated)
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// apportion according to largest remainder
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results := make([]sdk.Int, len(quotients))
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for _, qr := range quotients {
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results[qr.index] = qr.quo
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if !leftToAllocate.IsZero() {
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results[qr.index] = results[qr.index].Add(sdk.OneInt())
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leftToAllocate = leftToAllocate.Sub(sdk.OneInt())
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}
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}
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return results
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}
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type quoRem struct {
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index int
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quo sdk.Int
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rem sdk.Int
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}
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// totalInts adds together sdk.Ints
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func totalInts(is ...sdk.Int) sdk.Int {
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total := sdk.ZeroInt()
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for _, i := range is {
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total = total.Add(i)
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}
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return total
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}
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