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feat: add wallis product

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Hatter Jiang
2025-07-18 21:26:09 +08:00
parent 9e2d186449
commit 612ae3098b
2 changed files with 33 additions and 6 deletions
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3
README.md
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@@ -1,9 +1,10 @@
# math
| Class | Comments | MuBoard Link |
|--------------------------|--------------------|-----------------------------------------------------------------------------------------------------------------------------|
|-------------------------|--------------------|-----------------------------------------------------------------------------------------------------------------------------|
| ChineseRemainderTheorem | 中国剩余定理 | [chinese-remainder-theorem](https://hatter.ink/static/resource/muboard/?id=chinese-remainder-theorem&version=latest&full=1) |
| EulerTheorem | 欧拉定理 | [euler-theorem](https://hatter.ink/static/resource/muboard/?id=euler-theorem&version=latest&full=1) |
| ModularInv | 求乘法逆元【扩展欧几里得法】 | - |
| Sqrt10 | 求 $\sqrt{10}$【连分数】 | [resolve-sqrt-10](https://hatter.ink/static/resource/muboard/?id=resolve-sqrt-10&version=latest&full=1) |
| WallisProduct | 沃里斯乘积 | [wallis-product](https://hatter.ink/static/resource/muboard/?id=wallis-product&version=latest&full=1) |

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src/main/java/me/hatter/math/WallisProduct.java Normal file
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package me.hatter.math;
import java.math.BigDecimal;
import java.math.RoundingMode;
public class WallisProduct {
public static void main(String[] args) {
// 3.1415925750499739534746260502048989270653181072075621931977986489848855062212872415726332946132240849
System.out.println(pi());
}
public static BigDecimal pi() {
BigDecimal p = BigDecimal.valueOf(2);
for (long i = 1; i < 10000000; i++) {
BigDecimal doubleI = BigDecimal.valueOf(i * 2);
p = p.multiply(
doubleI.divide(doubleI.subtract(BigDecimal.ONE), 100, RoundingMode.FLOOR)
).multiply(
doubleI.divide(doubleI.add(BigDecimal.ONE), 100, RoundingMode.FLOOR)
);
p = p.divide(BigDecimal.ONE, 100, RoundingMode.FLOOR);
}
return p;
}
}