56 lines
1.6 KiB
C#
56 lines
1.6 KiB
C#
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namespace Environment.Utilities
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{
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using System.Linq;
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using UnityEngine;
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public class WeightedDistribution
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{
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// Could add a seed to random if ever needed
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readonly float[] cumulativeProbabilities;
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/// <summary>
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/// Class for sampling elements that have weights.
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/// </summary>
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public WeightedDistribution(float[] weights)
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{
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if (weights == null || weights.Length == 0)
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{
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Debug.LogError("Cannot create WeightedDistribution with a null or empty input!");
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}
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var sum = weights.Sum();
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this.cumulativeProbabilities = new float[weights.Length];
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var cumulativeProbability = 0f;
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for (var i = 0; i < weights.Length; i++)
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{
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cumulativeProbability += weights[i] / sum;
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this.cumulativeProbabilities[i] = cumulativeProbability;
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}
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}
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/// <summary>
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/// Samples the weighted distribution.
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/// </summary>
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public int Sample()
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{
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if (this.cumulativeProbabilities.Length == 1)
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{
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return 0;
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}
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var random = Random.value;
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for (var i = 0; i < this.cumulativeProbabilities.Length; i++)
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{
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if(random <= this.cumulativeProbabilities[i])
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{
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return i;
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}
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}
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Debug.LogWarning("Undefined behaviour! Defaulting to last element.");
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return this.cumulativeProbabilities.Length - 1;
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}
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}
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}
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