mirror of
https://github.com/autc04/Retro68.git
synced 2024-09-10 03:54:48 +00:00
37 lines
803 B
Go
37 lines
803 B
Go
// Copyright 2015 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// +build ignore
|
|
|
|
package runtime_test
|
|
|
|
import (
|
|
"math"
|
|
"runtime"
|
|
"testing"
|
|
)
|
|
|
|
func TestFastLog2(t *testing.T) {
|
|
// Compute the euclidean distance between math.Log2 and the FastLog2
|
|
// implementation over the range of interest for heap sampling.
|
|
const randomBitCount = 26
|
|
var e float64
|
|
|
|
inc := 1
|
|
if testing.Short() {
|
|
// Check 1K total values, down from 64M.
|
|
inc = 1 << 16
|
|
}
|
|
for i := 1; i < 1<<randomBitCount; i += inc {
|
|
l, fl := math.Log2(float64(i)), runtime.Fastlog2(float64(i))
|
|
d := l - fl
|
|
e += d * d
|
|
}
|
|
e = math.Sqrt(e)
|
|
|
|
if e > 1.0 {
|
|
t.Fatalf("imprecision on fastlog2 implementation, want <=1.0, got %f", e)
|
|
}
|
|
}
|