RR0/rr0.org

/**
 * Created by alammar on 12/23/16.
 */

// Zip it like python - https://stackoverflow.com/questions/4856717/javascript-equivalent-of-pythons-zip-function
function zip(arrays) {
  return arrays[0].map(function (_, i) {
    return arrays.map(function (array) {
      return array[i]
    })
  });
}

// Makes an element be drawn on top of other elements
// https://stackoverflow.com/questions/17786618/how-to-use-z-index-in-svg-elements
d3.selection.prototype.moveUp = function () {
  return this.each(function () {
    this.parentNode.appendChild(this);
  });
};

// Add commas to a big number fo readibility
// https://stackoverflow.com/questions/2901102/how-to-print-a-number-with-commas-as-thousands-separators-in-javascript
function numberWithCommas(x) {
  return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, " ");
}

// Calculate standard deviation of an array
// Needed for feature normalization
// https://derickbailey.com/2014/09/21/calculating-standard-deviation-with-array-map-and-array-reduce-in-javascript/
function standardDeviation(values) {
  var avg = average(values);
  var squareDiffs = values.map(function (value) {
    var diff = value - avg
    var sqrDiff = diff * diff
    return sqrDiff
  });
  var avgSquareDiff = average(squareDiffs);
  var stdDev = Math.sqrt(avgSquareDiff);
  return stdDev;
}

function average(data) {
  var sum = data.reduce(function (sum, value) {
    return sum + value;
  }, 0);
  var avg = sum / data.length;
  return avg;
}

// From https://cwestblog.com/2012/11/12/javascript-degree-and-radian-conversion/
// Converts from degrees to radians.
Math.radians = function (degrees) {
  return degrees * Math.PI / 180;
};

// Converts from radians to degrees.
Math.degrees = function (radians) {
  return radians * 180 / Math.PI;
};


roundPrecision = function (number, precision) {
  precision = Math.floor(precision);
  var factor = Math.pow(10, precision);
  var tempNumber = number * factor;
  var roundedTempNumber = Math.round(tempNumber);
  return roundedTempNumber / factor;
};

softmax = function (input) {

  if (!(input instanceof Array))
    throw(TypeError("Input passed into softmax() is not an array. softmax() expects an array. Input: " + input, "nnVizUtils.js"));

  var output = [], expSum = 0;

  // Calculate the sum of exp's
  for (var i = 0; i < input.length; i++) {
    if (!(typeof (input[i]) == "number")) {
      throw(TypeError("An element in the array passed to softmax() is not a number. softmax() expects an array of numbers. Input: " + input[i], "nnVizUtils.js"));
    }
    expSum = expSum + Math.exp(input[i]);
  }

  for (var j = 0; j < input.length; j++)
    output[j] = Math.exp(input[j]) / expSum;

  return output;
};


numberFormatter = function (value, digit_limit) {

  // default to 4 digits if not set
  digit_limit = digit_limit || 4;

  //If abs(value) has more than 6 digits, we'll show it as exp
  digits = Math.floor(Math.log10(Math.abs(value)) + 1);

  // Deals with numbers above 99999 and below -99999
  if (digits > digit_limit) {
    return value.toExponential(1);
  }

  // Deals with abs(numbers) between 99999 and 1
  if ((value > 1) || (value < -1)) {
    return roundPrecision(value, digit_limit - digits);
  }

  //Deals with decimals with less than digit_limit significant digits
  if (digits > -digit_limit) {
    return roundPrecision(value, digit_limit);
  }

  if (value == 0)
    return 0;
  return value.toExponential(1);

};