Corrected pow. Bump version to 0.1.5.

Author: quentinadam

Decimal.test.ts

@@ -385,29 +385,40 @@ Deno.test('mod', () => {
 
 Deno.test('pow', () => {
   const vectors: ({ a: Decimal; b: number } & ({ success: true; output: Decimal } | { success: false }))[] = [
+    { a: Decimal.from(2), b: 3, success: true, output: Decimal.from(8) },
+    { a: Decimal.from(2), b: 2, success: true, output: Decimal.from(4) },
     { a: Decimal.from(2), b: 1, success: true, output: Decimal.from(2) },
     { a: Decimal.from(2), b: 0, success: true, output: Decimal.from(1) },
     { a: Decimal.from(2), b: 2, success: true, output: Decimal.from(4) },
     { a: Decimal.from(2), b: -1, success: true, output: Decimal.from(0.5) },
     { a: Decimal.from(2), b: -2, success: true, output: Decimal.from(0.25) },
+    { a: Decimal.from(2), b: -3, success: true, output: Decimal.from(0.125) },
+    { a: Decimal.from(0.2), b: 3, success: true, output: Decimal.from(0.008) },
+    { a: Decimal.from(0.2), b: 2, success: true, output: Decimal.from(0.04) },
     { a: Decimal.from(0.2), b: 1, success: true, output: Decimal.from(0.2) },
     { a: Decimal.from(0.2), b: 0, success: true, output: Decimal.from(1) },
     { a: Decimal.from(0.2), b: 2, success: true, output: Decimal.from(0.04) },
     { a: Decimal.from(0.2), b: -1, success: true, output: Decimal.from(5) },
     { a: Decimal.from(0.2), b: -2, success: true, output: Decimal.from(25) },
+    { a: Decimal.from(0.2), b: -3, success: true, output: Decimal.from(125) },
+    { a: Decimal.from(3), b: 3, success: true, output: Decimal.from(27) },
+    { a: Decimal.from(3), b: 2, success: true, output: Decimal.from(9) },
     { a: Decimal.from(3), b: 1, success: true, output: Decimal.from(3) },
     { a: Decimal.from(3), b: 0, success: true, output: Decimal.from(1) },
-    { a: Decimal.from(3), b: 2, success: true, output: Decimal.from(9) },
     { a: Decimal.from(3), b: -1, success: false },
     { a: Decimal.from(3), b: -2, success: false },
+    { a: Decimal.from(3), b: -3, success: false },
   ];
   for (const vector of vectors) {
     const { a, b } = vector;
     if (vector.success) {
       const output = vector.output;
       const vectors = [{ a, b, output }, { a: a.neg(), b, output: b % 2 == 0 ? output : output.neg() }];
       for (const { a, b, output } of vectors) {
-        assert(a.pow(b).eq(output));
+        assert(
+          a.pow(b).eq(output),
+          `a: ${a.toString()}, b: ${b}, output: ${output.toString()}, result: ${a.pow(b).toString()}`,
+        );
       }
     } else {
       assert(wrap(() => a.pow(b)) instanceof Error);
@@ -576,3 +587,19 @@ Deno.test('lte0', () => {
     assert(input.lte0() === output);
   }
 });
+
+Deno.test('e', () => {
+  const vectors = [
+    { input: Decimal.from(12.3), exponent: 3, output: Decimal.from(12300) },
+    { input: Decimal.from(12.3), exponent: 2, output: Decimal.from(1230) },
+    { input: Decimal.from(12.3), exponent: 1, output: Decimal.from(123) },
+    { input: Decimal.from(12.3), exponent: 0, output: Decimal.from(12.3) },
+    { input: Decimal.from(12.3), exponent: -1, output: Decimal.from(1.23) },
+    { input: Decimal.from(12.3), exponent: -2, output: Decimal.from(0.123) },
+    { input: Decimal.from(12.3), exponent: -3, output: Decimal.from(0.0123) },
+  ];
+  for (const { input, exponent, output } of vectors) {
+    assert(input.e(exponent).eq(output));
+    assert(input.neg().e(exponent).eq(output.neg()));
+  }
+});

Decimal.ts

@@ -155,7 +155,7 @@ export default class Decimal {
    * @param exponent The integer exponent to raise 10 to.
    * @returns A new Decimal instance representing the result.
    */
-  e(exponent: bigint | number): Decimal {
+  e(exponent: number): Decimal {
     return this.mul(new Decimal(10n).pow(exponent));
   }
 
@@ -386,19 +386,16 @@ export default class Decimal {
    * @param value The integer exponent to raise to.
    * @returns A new Decimal instance representing the result of the exponentiation.
    */
-  pow(value: bigint | number): Decimal {
-    if (typeof value === 'number') {
-      assert(Number.isInteger(value), `Exponent must be an integer, got ${value}`);
-      value = BigInt(value);
-    }
-    if (value === 0n) {
+  pow(value: number): Decimal {
+    assert(Number.isInteger(value), `Exponent must be an integer, got ${value}`);
+    if (value === 0) {
       return Decimal.one;
-    } else if (value === 1n) {
+    } else if (value === 1) {
       return this;
-    } else if (value < 0n) {
+    } else if (value < 0) {
       return this.inv().pow(-value);
     } else {
-      return new Decimal(this.mantissa ** value, this.exponent * 2);
+      return new Decimal(this.mantissa ** BigInt(value), this.exponent * value);
     }
   }
 

deno.json

@@ -1,6 +1,6 @@
 {
   "name": "@quentinadam/decimal",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "exports": "./Decimal.ts",
   "imports": {
     "@quentinadam/assert": "jsr:@quentinadam/assert@^0.1.6"