Files
DayZ-Epoch/SQF/dayz_code/compile/fn_buildWeightedArray.sqf
2021-05-05 12:17:26 +06:00

56 lines
1.9 KiB
Plaintext

scriptName "Functions\arrays\fn_selectRandomWeighted.sqf";
/*
File: fn_selectRandomWeighted.sqf
Author: Joris-Jan van 't Land
Description:
Function to select a random item from an array, taking into account item weights.
The weights should be Numbers between 0 and 1, with a maximum precision of hundreds.
Parameter(s):
_this select 0: source Array (Array of Any Value)
_this select 1: weights (Array of Number)
Returns:
Any Value selected item
TODO:
[*] Algorithm is inefficient?
*/
private["_weights","_weighted","_weight"];
// _array = _this select 0;
_weights = _this select 1;
/*
//Parameter validation.
if ((typeName _array) != (typeName [])) exitWith {debugLog "Log: [selectRandomWeighted] Array (0) must be an Array!"; nil};
if ((typeName _weights) != (typeName [])) exitWith {debugLog "Log: [selectRandomWeighted] Weights (1) must be an Array!"; nil};
if ((count _array) > (count _weights)) exitWith {debugLog "Log: [selectRandomWeighted] There must be at least as many elements in Weights (1) as there are in Array (0)!"; nil};
*/
//Created weighted array of indices.
_weighted = [];
for "_i" from 0 to ((count _weights) - 1) do
{
_weight = _weights select _i;
//Ensure the weight is a Number.
//If it's not, set weight to 0 to exclude it.
if ((typeName _weight) != (typeName 0)) then {diag_log "Log: [selectRandomWeighted] Weights should be Numbers; weight set to 0!"; _weight = 0};
//The weight should be a Number between 0 and 1.
if (_weight < 0) then {diag_log "Log: [selectRandomWeighted] Weights should be more than or equal to 0; weight set to 0!"; _weight = 0};
//if (_weight > 1) then {debugLog "Log: [selectRandomWeighted] Weights should be less than or equal to 1; weight set to 1!"; _weight = 1};
//Normalize the weight for a precision of hundreds.
_weight = round(_weight * 100);
for "_k" from 0 to (_weight - 1) do
{
_weighted set [(count _weighted), _i];
};
};
_weighted