Weighted dice roll

[cookieclickerer33]

I need a way to make a weighted dice roll

Basically generate a random 0 or 1 based on 2 values whatever is higher has a greater chance of getting picked but not guaranteed

[pajamaclaws21]

In this example, the 0 has a 60% chance to be picked, whereas the 1 has a 40% chance to be picked. However, either number could be chosen.

Here is another example:

Again, the 0 has a 60% chance to be chosen (while the 1 has a 40% chance), but in this example, it is a lot easier to tweak the odds - just change the 6 and the 4 to whatever values you want.

[cookieclickerer33]

That’s helpful but is there a way to make it into a custom block that works a bit more logical
I need it for the ai system that uses probability to calculate between 2 actions

[pajamaclaws21]

I don't know what you mean by "more logical", but it is quite easy to put the solution I provided into a custom block.

[cookieclickerer33]

Yea that makes a bit more sense, what I meant by logical is turning it into a percentage

So like < ()% chance of true> and then using the 2 values to work out what the chance of true should be

[pajamaclaws21]

So something like this?

Then there is a (percent) chance of reporting true.

[cookieclickerer33]

Yea that works! Thank you!

[cookieclickerer33]

I also made my own version that a is a bit more lightweight but idk if it’s correct

[shadowmeowmeow32]

hmmm i think its kinda identical in a way but cant really tell one sec also did you need me for anything cookieclickerer?

[pajamaclaws21]

No, I think that works. Definitely a lot more lightweight.

[cookieclickerer33]

Not right now, but maybe you should work on chapter 2

[cookieclickerer33]

Now I need a way to calculate the chance to do the other thing from just the first chance

[qw23]

Here’s a more general solution, working for any number of possible outcomes (values) and corresponding weights (not necessarily adding up to 1):

[qw23]

Update: more efficient implementations of CUMULATIVE are included in topic: How do I implement a simple JavaScript function in Snap!, from post #3 onwards.