зеркало из https://github.com/CryptoPro/go.git
36 строки
736 B
Go
36 строки
736 B
Go
// run
|
|
|
|
// 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.
|
|
|
|
// This test computes the precision of the compiler's internal multiprecision floats.
|
|
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"math"
|
|
"runtime"
|
|
)
|
|
|
|
const ulp = (1.0 + (2.0 / 3.0)) - (5.0 / 3.0)
|
|
|
|
func main() {
|
|
// adjust precision depending on compiler
|
|
var prec float64
|
|
switch runtime.Compiler {
|
|
case "gc":
|
|
prec = math.Inf(1) // exact precision using rational arithmetic
|
|
case "gccgo":
|
|
prec = 256
|
|
default:
|
|
// unknown compiler
|
|
return
|
|
}
|
|
p := 1 - math.Log(math.Abs(ulp))/math.Log(2)
|
|
if math.Abs(p-prec) > 1e-10 {
|
|
fmt.Printf("BUG: got %g; want %g\n", p, prec)
|
|
}
|
|
}
|