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- // Copyright 2020 gorse Project Authors
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
- package base
- import (
- "testing"
- "github.com/chewxy/math32"
- mapset "github.com/deckarep/golang-set/v2"
- "github.com/stretchr/testify/assert"
- "github.com/thoas/go-funk"
- )
- const randomEpsilon = 0.1
- func TestRandomGenerator_MakeNormalMatrix(t *testing.T) {
- rng := NewRandomGenerator(0)
- vec := rng.NormalMatrix(1, 1000, 1, 2)[0]
- assert.False(t, math32.Abs(mean(vec)-1) > randomEpsilon)
- assert.False(t, math32.Abs(stdDev(vec)-2) > randomEpsilon)
- }
- func TestRandomGenerator_MakeUniformMatrix(t *testing.T) {
- rng := NewRandomGenerator(0)
- vec := rng.UniformMatrix(1, 1000, 1, 2)[0]
- assert.False(t, funk.MinFloat32(vec) < 1)
- assert.False(t, funk.MaxFloat32(vec) > 2)
- }
- func TestRandomGenerator_Sample(t *testing.T) {
- excludeSet := mapset.NewSet(0, 1, 2, 3, 4)
- rng := NewRandomGenerator(0)
- for i := 1; i <= 10; i++ {
- sampled := rng.Sample(0, 10, i, excludeSet)
- for j := range sampled {
- assert.False(t, excludeSet.Contains(sampled[j]))
- }
- }
- }
- func TestRandomGenerator_SampleInt32(t *testing.T) {
- excludeSet := mapset.NewSet[int32](0, 1, 2, 3, 4)
- rng := NewRandomGenerator(0)
- for i := 1; i <= 10; i++ {
- sampled := rng.SampleInt32(0, 10, i, excludeSet)
- for j := range sampled {
- assert.False(t, excludeSet.Contains(sampled[j]))
- }
- }
- }
- // mean of a slice of 32-bit floats.
- func mean(x []float32) float32 {
- return funk.SumFloat32(x) / float32(len(x))
- }
- // stdDev returns the sample standard deviation.
- func stdDev(x []float32) float32 {
- _, variance := meanVariance(x)
- return math32.Sqrt(variance)
- }
- // meanVariance computes the sample mean and unbiased variance, where the mean and variance are
- //
- // \sum_i w_i * x_i / (sum_i w_i)
- // \sum_i w_i (x_i - mean)^2 / (sum_i w_i - 1)
- //
- // respectively.
- // If weights is nil then all of the weights are 1. If weights is not nil, then
- // len(x) must equal len(weights).
- // When weights sum to 1 or less, a biased variance estimator should be used.
- func meanVariance(x []float32) (m, variance float32) {
- // This uses the corrected two-pass algorithm (1.7), from "Algorithms for computing
- // the sample variance: Analysis and recommendations" by Chan, Tony F., Gene H. Golub,
- // and Randall J. LeVeque.
- // note that this will panic if the slice lengths do not match
- m = mean(x)
- var (
- ss float32
- compensation float32
- )
- for _, v := range x {
- d := v - m
- ss += d * d
- compensation += d
- }
- variance = (ss - compensation*compensation/float32(len(x))) / float32(len(x)-1)
- return
- }
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