/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

//-----------------------------------------------------------------------------
var BUGNUMBER = 363040;
var summary = 'Array.prototype.reduce application in continued fraction';
var actual = '';
var expect = '';


//-----------------------------------------------------------------------------
test();
//-----------------------------------------------------------------------------

function test()
{
  printBugNumber(BUGNUMBER);
  printStatus (summary);
 

// Print x as a continued fraction in compact abbreviated notation and return
// the convergent [n, d] such that x - (n / d) <= epsilon.
  function contfrac(x, epsilon) {
    let i = Math.floor(x);
    let a = [i];
    x = x - i;
    let maxerr = x;
    while (maxerr > epsilon) {
      x = 1 / x;
      i = Math.floor(x);
      a.push(i);
      x = x - i;
      maxerr = x * maxerr / i;
    }
    print(a);
    return a.reduceRight(function (x, y) {return [x[0] * y + x[1], x[0]];}, [1, 0]);
  }

  if (!Array.prototype.reduceRight)
  {
    print('Test skipped. Array.prototype.reduceRight not implemented');
  }
  else
  {
// Show contfrac in action on some interesting numbers.
    for (num of [Math.PI, Math.sqrt(2), 1 / (Math.sqrt(Math.E) - 1)]) {
      print('Continued fractions for', num);
      for (eps of [1e-2, 1e-3, 1e-5, 1e-7, 1e-10]) {
        let frac = contfrac(num, eps);
        let est = frac[0] / frac[1];
        let err = num - est;
        print(frac, est, err);
      }
      print();
    }
  }

  reportCompare(expect, actual, summary);
}
