Question

say i generated a set of random numbers and put them into an array, (pre-sorted for simplicity) i’ll use javascript to show the math:

var vals = new Array(0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,...,10000);

then in a loop, i created a random number to serve as an index:

for(i=0;i<10000;i++){
    var random_index = Math.floor(Math.random() * 10000);
    var result = vals[random_index];
}

if you looked at this output on any kind of graph, the results (with enough iterations through that loop, will look pretty random and balanced)

what I want, is for the results of each access to favor smaller numbers, which incidentally here is array elements with a lower index.

for a visual example, imagine you’re trying to plot on a map where the fragments of a firework fell. most of those fragments would fall randomly within a vicinity but have a heavier concentration towards the middle. that’s a bit of an over-complicated example since it’s taking another dimension into account and uses physics to achieve the result, but it’s the same principal.

what operation should i perform on the random_index variable to make it ‘favor’ smaller numbers?

Answer 1

There are any number of things you can do.

For instance:

Math.floor(Math.sqrt(Math.random() * 10000^2));

The real question is, what kind of distribution do you want?