surrealpatch/util/math/quartile.go

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// Copyright © 2016 Abcum Ltd
//
// 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 math
import "math"
func Quartile(vals []float64) (float64, float64, float64) {
if len(vals) == 0 {
return math.NaN(), math.NaN(), math.NaN()
}
l := len(vals)
switch {
case l%2 == 0:
c1 := l / 2
c2 := l / 2
sort := Sort(vals)
return Median(sort[:c1]), Median(sort), Median(sort[c2:])
default:
c1 := (l - 1) / 2
c2 := c1 + 1
sort := Sort(vals)
return Median(sort[:c1]), Median(sort), Median(sort[c2:])
}
}
func InterQuartileRange(vals []float64) float64 {
if len(vals) == 0 {
return math.NaN()
}
q1, _, q3 := Quartile(vals)
return q3 - q1
}