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| package main | |
| import "fmt" | |
| import "math" | |
| func FastInvSqrt(x float32) float32 { | |
| xhalf := float32(0.5) * x | |
| i := math.Float32bits(x) | |
| i = 0x5f3759df - i>>1 | |
| x = math.Float32frombits(i) | |
| x = x * (1.5 - (xhalf * x * x)) | |
| return x | |
| } | |
| func main() { | |
| fmt.Printf("inv sqrt: %f\n", FastInvSqrt(4)) | |
| } |
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Ha. Turns out the implementations of math.Float32bits and math.Float32frombits use the unsafe package (source). Still, this version is more readable.