simple financial rate function in javascript

守給你的承諾、 提交于 2019-12-04 14:47:53

问题


I'm looking for a simple javascript financial RATE function, and I found this one. But it seems too difficult to understand. I want to simplify this function, and I need your help. If anyone has a simplest function, please answer. (It's a excel RATE function equivalent.)

var rate = function(nper, pmt, pv, fv, type, guess) {
  if (guess == null) guess = 0.01;
  if (fv == null) fv = 0;
  if (type == null) type = 0;

  var FINANCIAL_MAX_ITERATIONS = 128;//Bet accuracy with 128
  var FINANCIAL_PRECISION = 0.0000001;//1.0e-8

  var y, y0, y1, x0, x1 = 0, f = 0, i = 0;
  var rate = guess;
  if (Math.abs(rate) < FINANCIAL_PRECISION) {
     y = pv * (1 + nper * rate) + pmt * (1 + rate * type) * nper + fv;
  } else {
     f = Math.exp(nper * Math.log(1 + rate));
     y = pv * f + pmt * (1 / rate + type) * (f - 1) + fv;
  }
  y0 = pv + pmt * nper + fv;
  y1 = pv * f + pmt * (1 / rate + type) * (f - 1) + fv;

  // find root by Newton secant method
  i = x0 = 0.0;
  x1 = rate;
  while ((Math.abs(y0 - y1) > FINANCIAL_PRECISION) && (i < FINANCIAL_MAX_ITERATIONS)) {
     rate = (y1 * x0 - y0 * x1) / (y1 - y0);
     x0 = x1;
     x1 = rate;

     if (Math.abs(rate) < FINANCIAL_PRECISION) {
        y = pv * (1 + nper * rate) + pmt * (1 + rate * type) * nper + fv;
     } else {
        f = Math.exp(nper * Math.log(1 + rate));
        y = pv * f + pmt * (1 / rate + type) * (f - 1) + fv;
     }

     y0 = y1;
     y1 = y;
     ++i;
  }
  return rate;}

Thanks!


回答1:


The math is too complicated for me to understand, but this might be easier for you to read. Some of the variables have been renamed to make more sense, and it's formatted to be easier on your eyes

function rate(paymentsPerYear, paymentAmount, presentValue, futureValue, dueEndOrBeginning, interest)
{
    //If interest, futureValue, dueEndorBeginning was not set, set now
    if (interest == null)
        interest = 0.01;

    if (futureValue == null)
        futureValue = 0;

    if (dueEndOrBeginning == null)
        dueEndOrBeginning = 0;

    var FINANCIAL_MAX_ITERATIONS = 128;//Bet accuracy with 128
    var FINANCIAL_PRECISION = 0.0000001;//1.0e-8

    var y, y0, y1, x0, x1 = 0, f = 0, i = 0;
    var rate = interest;
    if (Math.abs(rate) < FINANCIAL_PRECISION)
    {
        y = presentValue * (1 + paymentsPerYear * rate) + paymentAmount * (1 + rate * dueEndOrBeginning) * paymentsPerYear + futureValue;
    }
    else
    {
        f = Math.exp(paymentsPerYear * Math.log(1 + rate));
        y = presentValue * f + paymentAmount * (1 / rate + dueEndOrBeginning) * (f - 1) + futureValue;
    }
    y0 = presentValue + paymentAmount * paymentsPerYear + futureValue;
    y1 = presentValue * f + paymentAmount * (1 / rate + dueEndOrBeginning) * (f - 1) + futureValue;

    // find root by Newton secant method
    i = x0 = 0.0;
    x1 = rate;
    while ((Math.abs(y0 - y1) > FINANCIAL_PRECISION)
        && (i < FINANCIAL_MAX_ITERATIONS))
    {
        rate = (y1 * x0 - y0 * x1) / (y1 - y0);
        x0 = x1;
        x1 = rate;

        if (Math.abs(rate) < FINANCIAL_PRECISION)
        {
            y = presentValue * (1 + paymentsPerYear * rate) + paymentAmount * (1 + rate * dueEndOrBeginning) * paymentsPerYear + futureValue;
        }
        else
        {
            f = Math.exp(paymentsPerYear * Math.log(1 + rate));
            y = presentValue * f + paymentAmount * (1 / rate + dueEndOrBeginning) * (f - 1) + futureValue;
        }

        y0 = y1;
        y1 = y;
        ++i;
    }
    return rate;
}


来源:https://stackoverflow.com/questions/12064793/simple-financial-rate-function-in-javascript

易学教程内所有资源均来自网络或用户发布的内容,如有违反法律规定的内容欢迎反馈
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!