distributions.js

// created by greg reimer ("gregreimer" at gmail) http://obadger.com/

function createHistogram(rFunc) {
	var arr = [];
	var size = 30;
	for (var i=0; i<size; i++){
		arr[i] = 0;
	}
	for (var i=0; i<1000000; i++){
		arr[Math.floor(rFunc() * size)]++;
	}
	var max = Math.max.apply(Math, arr);
	var factor = 50 / Math.max(1,max);
	var hist = arr.map(function(n){
		n = Math.ceil(n * factor);
		var result = '';
		for (var i=0; i<n; i++){
			result += '#';
		}
		return result;
	});
	hist.forEach(function(s){
		console.log(s);
	});
}

console.log('\n------------------\nsimple random number');
createHistogram(function(){
	return Math.random()
});

console.log('\n------------------\naverage of two random numbers');
createHistogram(function(){
	return (Math.random() + Math.random()) / 2;
});

console.log('\n------------------\naverage of three random numbers');
createHistogram(function(){
	return (Math.random() + Math.random() + Math.random()) / 3;
});

console.log('\n------------------\naverage of four random numbers');
createHistogram(function(){
	return (Math.random() + Math.random() + Math.random() + Math.random()) / 4;
});

console.log('\n------------------\nproduct of two random numbers');
createHistogram(function(){
	return Math.random() * Math.random()
});

console.log('\n------------------\nproduct of three random numbers');
createHistogram(function(){
	return Math.random() * Math.random() * Math.random()
});

console.log('\n------------------\nsquare of a random number');
createHistogram(function(){
	return Math.pow(Math.random(), 2)
});

console.log('\n------------------\ncube of a random number');
createHistogram(function(){
	return Math.pow(Math.random(), 3)
});

console.log('\n------------------\nchoose the higher of two random numbers');
createHistogram(function(){
	return Math.max(Math.random(), Math.random())
});

console.log('\n------------------\nchoose the higher of three random numbers');
createHistogram(function(){
	return Math.max(Math.random(), Math.random(), Math.random())
});

console.log('\n------------------\nchoose the higher of four random numbers');
createHistogram(function(){
	return Math.max(Math.random(), Math.random(), Math.random(), Math.random())
});

console.log('\n------------------\nsquare root of a random number');
createHistogram(function(){
	return Math.sqrt(Math.random())
});

console.log('\n------------------\ncube root of a random number');
createHistogram(function(){
	return Math.pow(Math.random(),1/3)
});

console.log('\n------------------\n1.4th root of a random number');
createHistogram(function(){
	return Math.pow(Math.random(),1/1.4)
});

console.log('\n------------------\nsquare root of the product of two random numbers');
createHistogram(function(){
	return Math.sqrt(Math.random()*Math.random())
});

console.log('\n------------------\nfifth root of the product of five random numbers');
createHistogram(function(){
	return Math.pow(Math.random()*Math.random()*Math.random()*Math.random()*Math.random(), 1/5)
});