求黄金分割比小数点后无限位（大数据运算，Go+Java语言实现）

求黄金分割比小数点后无限位（Go+Java语言实现）

理论上给出的代码可以精确无限位，但事实上太精确的数据对人类是无效的。
下面的代码是否已经精确到了小数点后2000位精度未测试，但1000多位精度是正确的，只需要调整程序中的常量可以精确到你想要精确的位数。

这是运行时求得的2000位：（CSND不会自动换行）

0.6180339887498948482045868343656381177203091798057628621354486227052604628189024497072072041893911374847540880753868917521266338622235369317931800607667263544333890865959395829056383226613199282902678806752087668925017116962070322210432162695486262963136144381497587012203408058879544547492461856953648644492410443207713449470495658467885098743394422125448770664780915884607499887124007652170575179788341662562494075890697040002812104276217711177780531531714101170466659914669798731761356006708748071013179523689427521948435305678300228785699782977834784587822891109762500302696156170025046433824377648610283831268330372429267526311653392473167111211588186385133162038400522216579128667529465490681131715993432359734949850904094762132229810172610705961164562990981629055520852479035240602017279974717534277759277862561943208275051312181562855122248093947123414517022373580577278616008688382952304592647878017889921990270776903895321968198615143780314997411069260886742962267575605231727775203536139362107673893764556060605921658946675955190040055590895022953094231248235521221241544400647034056573479766397239494994658457887303962309037503399385621024236902513868041457799569812244574717803417312645322041639723213404444948730231541767689375210306873788034417009395440962795589867872320951242689355730970450959568440175551988192180206405290551893494759260073485228210108819464454422231889131929468962200230144377026992300780308526118075451928877050210968424936271359251876077788466583615023891349333312231053392321362431926372891067050339928226526355620902979864247275977256550861548754357482647181414512700060238901620777322449943530889990950168032811219432048196438767586331479857191139781539780747615077221175082694586393204565209896985556781410696837288405874610337810544439094368358358138113116899385557697548414914453415091295407005019477548616307542264172939468036731980586183391832859913039607201445595044977921207612478564591616083705949878600697018940988640076443617093341727091914336501371

代码作者：天之，转载此文请注明出处和原作者

package main

import (
	"fmt"
)

type myInt int32

const (
	SIZE    = 120  //数组长度  数据长度小于：120*9
	TIMES   = 5150 //ab交换次数
	PRESIZE = 2000 //数字的有效位数
)

/*
*代码作者：天之
*博客：http://blog.csdn.net/WAPWO?viewmode=contents
 */
func main() {
	a, b, tmp, res := make([]myInt, SIZE), make([]myInt, SIZE), make([]myInt, SIZE), make([]byte, PRESIZE)
	initAB(a, b)
	gab(a, b, tmp)
	//printBigNum(a)
	//printBigNum(b)
	bigNumDiv(a, b, tmp, res)
	fmt.Println(res)
}

/*复制整型数组*/
func cpyMyIntArr(d, s []myInt) {
	for i := 0; i < SIZE; i++ {
		d[i] = s[i]
	}
}

/*大数之和，a=a+b*/
func bigNumSum(a, b []myInt) {
	for i := 0; i < SIZE; i++ {
		count := a[i] + b[i]
		//因为已知a[i]和b[i]都是九位数内的
		if count > 1000000000 {
			a[i+1] += 1
			a[i] = count - 1000000000
		} else {
			a[i] = count
		}
	}
	//如果不存在a[i+1]，这时就溢出了，在输入时需要控制
}

/*十倍值，a=10*a*/
func bigNum10(a, tmp []myInt) {
	cpyMyIntArr(tmp, a)
	for i := 0; i < 9; i++ {
		bigNumSum(a, tmp)
	}
}

/*大数之差，a=a-b*/
func bigNumDif(a, b, tmp []myInt) int16 {
	cpyMyIntArr(tmp, a)
	for i := 0; i < SIZE; i++ {
		count := a[i] - b[i]
		if count < 0 {
			if i < SIZE-1 {
				a[i+1] -= 1
				a[i] = 1000000000 + count
			} else {
				cpyMyIntArr(a, tmp)
				return 0
			}

		} else {
			a[i] = count
		}

	}
	for i := SIZE - 1; i >= 0; i-- {
		if a[i] < 0 {
			cpyMyIntArr(a, tmp)
			return 0
		}
	}
	return 1
}

/*模拟除法运算res=b/a，进入运算时b<a*/
func bigNumDiv(a, b, tmp []myInt, res []byte) {
	var count byte
	for i := 0; i < PRESIZE; i++ {
		count = 0
		for bigNumDif(b, a, tmp) == 1 {
			count++
		}
		res[i] = count
		bigNum10(b, tmp)
	}
}

/*生成比例数，b/a --> a/(b+a)*/
func gab(a, b, tmp []myInt) {
	for i := 0; i < TIMES; i++ {
		cpyMyIntArr(tmp, a)
		bigNumSum(a, b)
		cpyMyIntArr(b, tmp)
	}
}

/*初始化ab数组*/
func initAB(a, b []myInt) {
	for i := 1; i < SIZE; i++ {
		a[i] = 0
		b[i] = 0
	}
	a[0] = 3
	b[0] = 2
}

/*打印大数据数组*/
func printBigNum(a []myInt) {
	for i := SIZE - 1; i >= 0; i-- {
		fmt.Printf("%10d", a[i])
	}
	fmt.Println()
}

import java.math.BigDecimal;
public class Demo {
	static int i=0;
	public static void main(String args[]){
		BigDecimal x=new BigDecimal(Double.parseDouble("0.5"));
		System.out.println(fun(1,x));
	}
	static BigDecimal fun(int times,BigDecimal n){
		//n'=1/(1+n)
		BigDecimal a=new BigDecimal(Double.parseDouble("1"));
		if(times>1000){
			n=a.add( n );
			return a.divide(n,300,BigDecimal.ROUND_HALF_UP);
		}else{
			n=a.add( n );
			return fun(times+1,a.divide(n,300,BigDecimal.ROUND_HALF_UP));
		}
	}
}

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