94 lines
2.1 KiB
Go
94 lines
2.1 KiB
Go
// Copyright 2017 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package distribution
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import (
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"sync"
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"testing"
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)
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func TestDistribution(t *testing.T) {
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// These tests come from examples in https://en.wikipedia.org/wiki/Percentile#The_nearest-rank_method
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tests := []struct {
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// values in distribution
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vals []int
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// percentiles and expected percentile values
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pp []float64
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vv []int
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}{
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{
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vals: []int{15, 20, 35, 40, 50},
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pp: []float64{0.05, 0.3, 0.4, 0.5, 1},
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vv: []int{15, 20, 20, 35, 50},
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},
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{
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vals: []int{3, 6, 7, 8, 8, 10, 13, 15, 16, 20},
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pp: []float64{0.25, 0.5, 0.75, 1},
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vv: []int{7, 8, 15, 20},
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},
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{
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vals: []int{3, 6, 7, 8, 8, 9, 10, 13, 15, 16, 20},
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pp: []float64{0.25, 0.5, 0.75, 1},
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vv: []int{7, 9, 15, 20},
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},
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}
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maxVal := 0
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for _, tst := range tests {
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for _, v := range tst.vals {
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if maxVal < v {
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maxVal = v
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}
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}
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}
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for _, tst := range tests {
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d := New(maxVal + 1)
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for _, v := range tst.vals {
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d.Record(v)
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}
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for i, p := range tst.pp {
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got, want := d.Percentile(p), tst.vv[i]
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if got != want {
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t.Errorf("d=%v, d.Percentile(%f)=%d, want %d", d, p, got, want)
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}
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}
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}
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}
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func TestRace(t *testing.T) {
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const N int = 1e3
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const parallel = 2
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d := New(N)
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var wg sync.WaitGroup
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wg.Add(parallel)
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for i := 0; i < parallel; i++ {
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go func() {
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for i := 0; i < N; i++ {
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d.Record(i)
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}
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wg.Done()
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}()
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}
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for i := 0; i < N; i++ {
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if p := d.Percentile(0.5); p > N {
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t.Fatalf("d.Percentile(0.5)=%d, expected to be at most %d", p, N)
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}
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}
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}
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