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/* |
Copyright (c) 2004-2006, The Dojo Foundation |
All Rights Reserved. |
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Licensed under the Academic Free License version 2.1 or above OR the |
modified BSD license. For more information on Dojo licensing, see: |
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http://dojotoolkit.org/community/licensing.shtml |
*/ |
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dojo.provide("dojo.math"); |
dojo.math.degToRad = function (x) { |
return (x * Math.PI) / 180; |
}; |
dojo.math.radToDeg = function (x) { |
return (x * 180) / Math.PI; |
}; |
dojo.math.factorial = function (n) { |
if (n < 1) { |
return 0; |
} |
var retVal = 1; |
for (var i = 1; i <= n; i++) { |
retVal *= i; |
} |
return retVal; |
}; |
dojo.math.permutations = function (n, k) { |
if (n == 0 || k == 0) { |
return 1; |
} |
return (dojo.math.factorial(n) / dojo.math.factorial(n - k)); |
}; |
dojo.math.combinations = function (n, r) { |
if (n == 0 || r == 0) { |
return 1; |
} |
return (dojo.math.factorial(n) / (dojo.math.factorial(n - r) * dojo.math.factorial(r))); |
}; |
dojo.math.bernstein = function (t, n, i) { |
return (dojo.math.combinations(n, i) * Math.pow(t, i) * Math.pow(1 - t, n - i)); |
}; |
dojo.math.gaussianRandom = function () { |
var k = 2; |
do { |
var i = 2 * Math.random() - 1; |
var j = 2 * Math.random() - 1; |
k = i * i + j * j; |
} while (k >= 1); |
k = Math.sqrt((-2 * Math.log(k)) / k); |
return i * k; |
}; |
dojo.math.mean = function () { |
var array = dojo.lang.isArray(arguments[0]) ? arguments[0] : arguments; |
var mean = 0; |
for (var i = 0; i < array.length; i++) { |
mean += array[i]; |
} |
return mean / array.length; |
}; |
dojo.math.round = function (number, places) { |
if (!places) { |
var shift = 1; |
} else { |
var shift = Math.pow(10, places); |
} |
return Math.round(number * shift) / shift; |
}; |
dojo.math.sd = dojo.math.standardDeviation = function () { |
var array = dojo.lang.isArray(arguments[0]) ? arguments[0] : arguments; |
return Math.sqrt(dojo.math.variance(array)); |
}; |
dojo.math.variance = function () { |
var array = dojo.lang.isArray(arguments[0]) ? arguments[0] : arguments; |
var mean = 0, squares = 0; |
for (var i = 0; i < array.length; i++) { |
mean += array[i]; |
squares += Math.pow(array[i], 2); |
} |
return (squares / array.length) - Math.pow(mean / array.length, 2); |
}; |
dojo.math.range = function (a, b, step) { |
if (arguments.length < 2) { |
b = a; |
a = 0; |
} |
if (arguments.length < 3) { |
step = 1; |
} |
var range = []; |
if (step > 0) { |
for (var i = a; i < b; i += step) { |
range.push(i); |
} |
} else { |
if (step < 0) { |
for (var i = a; i > b; i += step) { |
range.push(i); |
} |
} else { |
throw new Error("dojo.math.range: step must be non-zero"); |
} |
} |
return range; |
}; |
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