Prepare 1.5.0 release

node_modules/add/index.js

@@ -0,0 +1,177 @@
+(function (root, factory) {
+  "use strict";
+
+  // AMD
+  if (typeof define === 'function' && define.amd) {
+    define([], factory);
+  }
+  // CommonJS
+  else if (typeof exports === 'object') {
+    module.exports = factory();
+  }
+  // Browser
+  else {
+    root.add = factory();
+  }
+})(this, function () {
+  "use strict";
+
+  // The minimum machine rounding error
+  var Epsilon = Math.pow(2, -53)
+    , EpsilonReciprocal = (1 / Epsilon)
+      /// The smallest positive number that can be represented
+    , Eta = Math.pow(2, -1074)
+      // limitB is a constant used in the transform function
+    , limitB = 0.5 * EpsilonReciprocal * Eta
+
+  /**
+  * S. M. RUMP, T. OGITA AND S. OISHI
+  * http://www.ti3.tu-harburg.de/paper/rump/RuOgOi07I.pdf
+  */
+
+  // Page 8
+  // x is result, y is error
+  // third is so the array is allocated for 4 spaces
+  // it speeds up transform
+  function fastTwoSum(a, b) {
+    var x = a + b
+      , q = x - a
+      , y = b - q
+
+    return [x, y, null]
+  }
+
+  // Page 12
+  // p = q + p'
+  // sigma is a power of 2 greater than or equal to |p|
+  function extractScalar(sigma, p) {
+    var q = (sigma + p) - sigma
+      , pPrime = p - q
+
+    return [q, pPrime]
+  }
+
+  // Page 12
+  function extractVector(sigma, p) {
+    var tau = 0.0
+      , extracted
+      , i = 0
+      , ii = p.length
+      , pPrime = new Array(ii)
+
+    for(; i<ii; ++i) {
+      extracted = extractScalar(sigma, p[i])
+      pPrime[i] = extracted[1]
+      tau += extracted[0]
+    }
+
+    return [tau, pPrime]
+  }
+
+  // Finds the immediate power of 2 that is larger than p
+  //// in a fast way
+  function nextPowerTwo (p) {
+    var q = EpsilonReciprocal * p
+      , L = Math.abs((q + p) - q)
+
+    if(L === 0)
+      return Math.abs(p)
+
+    return L
+  }
+
+  // Helper, gets the maximum of the absolute values of an array
+  function maxAbs(arr) {
+    var i = 0
+      , ii = arr.length
+      , best = -1
+
+    for(; i<ii; ++i) {
+      if(Math.abs(arr[i]) > best) {
+        best = arr[i]
+      }
+    }
+
+    return best
+  }
+
+  function transform (p) {
+    var mu = maxAbs(p)
+      , M
+      , sigmaPrime
+      , tPrime
+      , t
+      , tau
+      , sigma
+      , extracted
+      , res
+
+        // Not part of the original paper, here for optimization
+      , temp
+      , bigPow
+      , limitA
+      , twoToTheM
+
+    if(mu === 0) {
+      return [0, 0, p, 0]
+    }
+
+    M = nextPowerTwo(p.length + 2)
+    twoToTheM = Math.pow(2, M)
+    bigPow = 2 * twoToTheM // equiv to Math.pow(2, 2 * M), faster
+    sigmaPrime = twoToTheM * nextPowerTwo(mu)
+    tPrime = 0
+
+    do {
+      t = tPrime
+      sigma = sigmaPrime
+      extracted = extractVector(sigma, p)
+      tau = extracted[0]
+      tPrime = t + tau
+      p = extracted[1]
+
+      if(tPrime === 0) {
+        return transform(p)
+      }
+
+      temp = Epsilon * sigma
+      sigmaPrime = twoToTheM * temp
+      limitA = bigPow * temp
+    }
+    while( Math.abs(tPrime) < limitA && sigma > limitB )
+
+    // res already allocated for 4
+    res = fastTwoSum(t, tau)
+    res[2] = p
+
+    return res
+  }
+
+  function dumbSum(p) {
+    var i, ii, sum = 0.0
+    for(i=0, ii=p.length; i<ii; ++i) {
+      sum += p[i]
+    }
+    return sum
+  }
+
+  function accSum(p) {
+
+    // Zero length array, or all values are zeros
+    if(p.length === 0 || maxAbs(p) === 0) {
+      return 0
+    }
+
+    var tfmd = transform(p)
+
+    return tfmd[0] + (tfmd[1] +dumbSum(tfmd[2]))
+  }
+
+
+  // exports
+  accSum.dumbSum = dumbSum;
+  accSum.fastTwoSum = fastTwoSum;
+  accSum.nextPowerTwo = nextPowerTwo;
+  return accSum;
+});
+