Dividing a number into random unequal parts [closed]

Question

So I am trying to make a script that will randomly split a value of 4 into 12 different variables. I can't think of a good way to do this properly. I thought about randomizing numbers so that they are close to 0.33 (1/12 of 4) but that would often lead to the last few numbers being underprioritized. Anyone tried anything like this before or have any great ideas for how to make this as random and evenly uneven as possible?

Answer 1

Generate 12 random numbers from your favourite random number generator, call them r1..r12.

Add them all up, call the sum sum.

Your first random fraction of 4 is (r1/sum)*4. The rest should be obvious.

Answer 2

Generate any random number greater than 1 and after rescale to required sum.

Example:

• Required sum: 4
• Random Numbers: 1 2 3 4 5 6 7 8 9 10 11 12
• Sum = 78
• Rescaled numbers:

1 rescaled to (1*4) / 78

2 rescaled to (2*4) / 78

...

12 rescaled to (12*4) / 78

Answer 3

The following algorithm provides uniformly distributed partitions, assuming that it is possible to generate uniformly distributed random numbers over a continuous range (or, at least, over a discrete range with sufficiently many possible values that the odds of duplication are negligible).

To produce a partition of t into k values:

• Generate k-1 uniformly distributed values in the range [0, t].

• Sort them, and add 0 at the beginning and t at the end.

• Use the adjacent differences as the partition.