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/*
Copyright (c) 2004-2006, The Dojo Foundation
All Rights Reserved.
Licensed under the Academic Free License version 2.1 or above OR the
modified BSD license. For more information on Dojo licensing, see:
http://dojotoolkit.org/community/licensing.shtml
*/
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;
};