istio.io/istio@v0.0.0-20240520182934-d79c90f27776/pkg/test/loadbalancersim/timeseries/data.go (about)

     1  //  Copyright Istio Authors
     2  //
     3  //  Licensed under the Apache License, Version 2.0 (the "License");
     4  //  you may not use this file except in compliance with the License.
     5  //  You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  //  Unless required by applicable law or agreed to in writing, software
    10  //  distributed under the License is distributed on an "AS IS" BASIS,
    11  //  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  //  See the License for the specific language governing permissions and
    13  //  limitations under the License.
    14  
    15  package timeseries
    16  
    17  import (
    18  	"math"
    19  	"sort"
    20  )
    21  
    22  var (
    23  	negativeInfinity = math.Inf(-1)
    24  	infinity         = math.Inf(1)
    25  	nan              = math.NaN()
    26  )
    27  
    28  type Data []float64
    29  
    30  func (d Data) Min() float64 {
    31  	return d.sorted().min()
    32  }
    33  
    34  func (d Data) Max() float64 {
    35  	return d.sorted().max()
    36  }
    37  
    38  func (d Data) Median() float64 {
    39  	return d.Quantile(0.5)
    40  }
    41  
    42  func (d Data) Mean() float64 {
    43  	total := float64(0)
    44  	for _, v := range d {
    45  		total += v
    46  	}
    47  	return total / float64(len(d))
    48  }
    49  
    50  func (d Data) Quantile(phi float64) float64 {
    51  	return d.sorted().quantile(phi)
    52  }
    53  
    54  func (d Data) Quantiles(phis ...float64) []float64 {
    55  	return d.sorted().quantiles(phis...)
    56  }
    57  
    58  func (d Data) Copy() Data {
    59  	out := make(Data, 0, len(d))
    60  	out = append(out, d...)
    61  	return out
    62  }
    63  
    64  func (d Data) sorted() sorted {
    65  	out := make(sorted, 0, len(d))
    66  	out = append(out, d...)
    67  
    68  	sort.Float64s(out)
    69  	return out
    70  }
    71  
    72  type sorted []float64
    73  
    74  func (s sorted) min() float64 {
    75  	if len(s) == 0 {
    76  		return negativeInfinity
    77  	}
    78  
    79  	return s[0]
    80  }
    81  
    82  func (s sorted) max() float64 {
    83  	if len(s) == 0 {
    84  		return infinity
    85  	}
    86  
    87  	return s[len(s)-1]
    88  }
    89  
    90  func (s sorted) quantile(phi float64) float64 {
    91  	if len(s) == 0 || math.IsNaN(phi) {
    92  		return nan
    93  	}
    94  	if phi <= 0 {
    95  		return s.min()
    96  	}
    97  	if phi >= 1 {
    98  		return s.max()
    99  	}
   100  	idx := uint(phi*float64(len(s)-1) + 0.5)
   101  	if idx >= uint(len(s)) {
   102  		idx = uint(len(s) - 1)
   103  	}
   104  	return s[idx]
   105  }
   106  
   107  func (s sorted) quantiles(phis ...float64) []float64 {
   108  	out := make([]float64, 0, len(phis))
   109  	for _, phi := range phis {
   110  		out = append(out, s.quantile(phi))
   111  	}
   112  	return out
   113  }