Merge branch 'feat/bigint-sqrt'

oraidex · Nov 29, 2023 · ef318e7 · ef318e7
2 parents 0767b2d + 2a50511
commit ef318e7
Showing 1 changed file with 30 additions and 0 deletions.
diff --git a/packages/oraidex-common/src/bigdecimal.ts b/packages/oraidex-common/src/bigdecimal.ts
@@ -116,6 +116,36 @@ export class BigDecimal {
     return this;
   }
 
+  static rootNth(value: DecimalLike, k = 2n) {
+    const big = new BigDecimal(value);
+
+    // re-calculate bigInt
+    const bigValue = big.bigInt * 10n ** BigInt(big._decimals);
+    if (bigValue < 0n) {
+      throw "negative number is not supported";
+    }
+
+    let o = 0n;
+    let x = bigValue;
+    let limit = 100;
+
+    while (x ** k !== k && x !== o && --limit) {
+      o = x;
+      x = ((k - 1n) * x + bigValue / x ** (k - 1n)) / k;
+    }
+
+    big.bigInt = x;
+    return big;
+  }
+
+  static sqrt(value: DecimalLike) {
+    return BigDecimal.rootNth(value);
+  }
+
+  sqrt() {
+    return BigDecimal.rootNth(this);
+  }
+
   add(other: DecimalLike) {
     return this.clone().iadd(other);
   }