Performance comparison between two big integer implementations in Dart

gistfile1.dart

/**
 * Results for the Dart VM (v1.7.2)
 * Duration for bignum's BigInteger: 59s
 * Duration for rational's BigInt: 197s
 *
 * Results for dart2js in Chrome (v39.0.2171.62)
 * Duration for bignum's BigInteger: 77s
 * Duration for rational's BigInt: 474s
 */

library bigint_test;

import "package:bignum/bignum.dart";
import "package:rational/bigint.dart";

void bignumTest() {
  BigInteger o = BigInteger.ONE;
  BigInteger f = o;
  BigInteger i = BigInteger.TWO;
  BigInteger l = new BigInteger("99999");
  Stopwatch timer = new Stopwatch()..start();
  while(i < l) {
    f = f * i;
    i = i + o;
  }
  timer.stop();
  print("Duration for bignum's BigInteger: ${timer.elapsed.inSeconds}s");
}

void rationalTest() {
  BigInt o = new BigInt.fromJsInt(1);
  BigInt f = o;
  BigInt i = new BigInt.fromJsInt(2);
  BigInt l = new BigInt.fromJsInt(99999);
  Stopwatch timer = new Stopwatch()..start();
  while(i < l) {
    f = f * i;
    i = i + o;
  }
  timer.stop();
  print("Duration for rational's BigInt: ${timer.elapsed.inSeconds}s");
}

void main() {
  bignumTest();
  rationalTest();
}

Consider using https://github.com/dart-lang/benchmark_harness ?

Have you considered benchmarking the VM's built-in big integer implementation? It would be a fun comparison and it's an area that has improved quite a lot lately (1.9.0-dev.0.0 has lots of optimizations).