59 lines
1.1 KiB
Go
59 lines
1.1 KiB
Go
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package main
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import (
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"fmt"
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"math"
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)
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const PRECISION = 0.000000001
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const maxRunLoop = 100
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func DichotomyEquation(a float64, b float64, f func(input float64) float64) (float64, int) {
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mid := (a + b) / 2.0
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count := 0
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for ; (b - a) > PRECISION; {
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if f(a)*f(mid) < 0.0 {
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b = mid
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} else {
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a = mid
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}
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mid = (a + b) / 2.0
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count++
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}
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return mid, count
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}
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func target(x float64) float64 {
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return (2.0*x*x + 3.2*x - 1.8)
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}
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func CalcDerivative(f func(input float64) float64, x float64) float64 {
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return (f(x+0.000005) - f(x-0.000005)) / 0.00001
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}
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func NewtonRaphson(f func(input float64) float64, x0 float64) (float64, int) {
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var x float64 = math.MaxInt64
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var count int = 0
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for count < maxRunLoop {
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x1 := x0 - f(x0)/CalcDerivative(f, x0)
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if (math.Abs(x1-x0) < PRECISION) {
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x = x1
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break
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}
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x0 = x1
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count++
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}
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return x, count
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}
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func main() {
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fmt.Println("Use DichotomyEquation method")
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mid, times := DichotomyEquation(-8.0, 8.0, target)
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fmt.Printf("values is %f, run %d times", mid, times)
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fmt.Println("Use Newton Raphson method")
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mid1, times1 := NewtonRaphson(target, -8.0)
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fmt.Printf("values is %f, run %d times", mid1, times1)
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}
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