77 lines
1.4 KiB
Go
77 lines
1.4 KiB
Go
package stats
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import (
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"math/rand"
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"sort"
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)
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// Sample returns sample from input with replacement or without
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func Sample(input Float64Data, takenum int, replacement bool) ([]float64, error) {
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if input.Len() == 0 {
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return nil, EmptyInputErr
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}
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length := input.Len()
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if replacement {
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result := Float64Data{}
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rand.Seed(unixnano())
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// In every step, randomly take the num for
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for i := 0; i < takenum; i++ {
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idx := rand.Intn(length)
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result = append(result, input[idx])
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}
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return result, nil
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} else if !replacement && takenum <= length {
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rand.Seed(unixnano())
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// Get permutation of number of indexies
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perm := rand.Perm(length)
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result := Float64Data{}
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// Get element of input by permutated index
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for _, idx := range perm[0:takenum] {
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result = append(result, input[idx])
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}
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return result, nil
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}
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return nil, BoundsErr
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}
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// StableSample like stable sort, it returns samples from input while keeps the order of original data.
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func StableSample(input Float64Data, takenum int) ([]float64, error) {
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if input.Len() == 0 {
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return nil, EmptyInputErr
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}
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length := input.Len()
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if takenum <= length {
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rand.Seed(unixnano())
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perm := rand.Perm(length)
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perm = perm[0:takenum]
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// Sort perm before applying
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sort.Ints(perm)
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result := Float64Data{}
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for _, idx := range perm {
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result = append(result, input[idx])
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}
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return result, nil
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}
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return nil, BoundsErr
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}
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