Scala BigDecimal 如何显示更多小数？

发布于 2024-12-26 08:02:10 字数 1129 浏览 5 评论 0原文

首先，我知道有一个关于 1 除以 3 的类似主题。但是，我的代码完全不同，我不知道如何将那里给出的信息应用到我的情况。我将不胜感激任何和所有的帮助。

我在 Scala 中制作了一个 Pi 计算器，并在代码末尾打印了结果。但是，我想要更多的小数位数，但我不知道如何实现这一点。我当前的输出是：

Expected decimals: 34
3.141592653589793238462643383279500

这是代码：

package theBrain
object Calculator 
{
def main(args: Array[String]) 
{

var i = 100
var j = 100
var lastValueOnFirstLine = j+i
var array = new Array [BigDecimal] (0)

var counter = i-1

for (d <- j to lastValueOnFirstLine by 1)
{
  var almostPi = BigDecimal(0)
  var pi = BigDecimal(0)

  for (b <- 0 to d by 1)
  {
      var partialAnswer = (if (b%2 != 0) {-1} else {1} )/((BigDecimal(2)*BigDecimal(b))+BigDecimal(1))
      almostPi = partialAnswer + almostPi

  }
  pi = 4*almostPi
 array = array:+pi
}

for (z <- counter to 0 by -1){
var array2 = new Array [BigDecimal] (0)
var length = array.length -2
for (a <- 0 to length by 1){

var result = (array(a)+array(a+1))/2
array2 = array2:+result
}
array = array2
counter -= 1
}

for (element <- array) {
println("Expected decimals: " + element.precision)
println(element)
}

}
}

原文

First of all, I am aware that there is a similar topic regarding the division of 1 by 3. However, my code is quite different and I don't know how to apply the information given there to my situation. I would appreciate any and all help.

I made a Pi calculator in Scala and at the end of the code I print the result. However, I want to have a much larger number of decimals and I don't know how to achieve that. My current output is :

Expected decimals: 34
3.141592653589793238462643383279500

Here's the code:

package theBrain
object Calculator 
{
def main(args: Array[String]) 
{

var i = 100
var j = 100
var lastValueOnFirstLine = j+i
var array = new Array [BigDecimal] (0)

var counter = i-1

for (d <- j to lastValueOnFirstLine by 1)
{
  var almostPi = BigDecimal(0)
  var pi = BigDecimal(0)

  for (b <- 0 to d by 1)
  {
      var partialAnswer = (if (b%2 != 0) {-1} else {1} )/((BigDecimal(2)*BigDecimal(b))+BigDecimal(1))
      almostPi = partialAnswer + almostPi

  }
  pi = 4*almostPi
 array = array:+pi
}

for (z <- counter to 0 by -1){
var array2 = new Array [BigDecimal] (0)
var length = array.length -2
for (a <- 0 to length by 1){

var result = (array(a)+array(a+1))/2
array2 = array2:+result
}
array = array2
counter -= 1
}

for (element <- array) {
println("Expected decimals: " + element.precision)
println(element)
}

}
}

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

故人的歌 2025-01-02 08:02:10

创建 BigDecimal 实例时，您必须提供不同的 java.math.MathContext。请注意，这会影响计算的精度，而不仅仅是输出中打印的小数位数。这与单纯的数字格式化有很大不同。

scala> BigDecimal(1) / 3
res0: scala.math.BigDecimal = 0.3333333333333333333333333333333333

scala> res0.precision
res1: Int = 34

scala> BigDecimal(1, new java.math.MathContext(50)) / 3
res2: scala.math.BigDecimal = 0.33333333333333333333333333333333333333333333333333

scala> res2.precision
res3: Int = 50

You have to supply a different java.math.MathContext when you create your instances of BigDecimal. Note that this effects the precision of the calculation, not only how many decimals are printed on output. This is quite different from the mere formatting of numbers.

scala> BigDecimal(1) / 3
res0: scala.math.BigDecimal = 0.3333333333333333333333333333333333

scala> res0.precision
res1: Int = 34

scala> BigDecimal(1, new java.math.MathContext(50)) / 3
res2: scala.math.BigDecimal = 0.33333333333333333333333333333333333333333333333333

scala> res2.precision
res3: Int = 50

回复收藏 0 原文

~没有更多了~