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Added GetRandomEntry and GetRandomWeightedEntry to SingleRandom

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Ell 2023-08-07 19:00:34 +02:00
parent 2c7ffee427
commit 7e64b8a990
3 changed files with 66 additions and 21 deletions
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1
CHANGELOG.md
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@ -17,6 +17,7 @@ Jump to version:
Additions
- Added GraphicsExtensions.WithRenderTargets, a multi-target version of WithRenderTarget
- Added Zero, One, Linear and Clamp to Easings
- Added GetRandomEntry and GetRandomWeightedEntry to SingleRandom
Fixes
- Fixed TextInput not working correctly when using surrogate pairs

50
MLEM/Extensions/RandomExtensions.cs
View file

@ -16,8 +16,7 @@ namespace MLEM.Extensions {
/// <typeparam name="T">The entries' type</typeparam>
/// <returns>A random entry</returns>
public static T GetRandomEntry<T>(this Random random, ICollection<T> entries) {
// ElementAt internally optimizes for IList access so we don't have to here
return entries.ElementAt(random.Next(entries.Count));
return RandomExtensions.GetRandomEntry(entries, random.NextSingle());
}
/// <summary>
@ -31,28 +30,12 @@ namespace MLEM.Extensions {
/// <returns>A random entry, based on the entries' weight</returns>
/// <exception cref="IndexOutOfRangeException">If the weight function returns different weights for the same entry</exception>
public static T GetRandomWeightedEntry<T>(this Random random, ICollection<T> entries, Func<T, int> weightFunc) {
var totalWeight = entries.Sum(weightFunc);
var goalWeight = random.Next(totalWeight);
var currWeight = 0;
foreach (var entry in entries) {
currWeight += weightFunc(entry);
if (currWeight > goalWeight)
return entry;
}
throw new IndexOutOfRangeException();
return RandomExtensions.GetRandomWeightedEntry(entries, weightFunc, random.NextSingle());
}
/// <inheritdoc cref="GetRandomWeightedEntry{T}(System.Random,System.Collections.Generic.ICollection{T},System.Func{T,int})"/>
public static T GetRandomWeightedEntry<T>(this Random random, ICollection<T> entries, Func<T, float> weightFunc) {
var totalWeight = entries.Sum(weightFunc);
var goalWeight = random.NextDouble() * totalWeight;
var currWeight = 0F;
foreach (var entry in entries) {
currWeight += weightFunc(entry);
if (currWeight > goalWeight)
return entry;
}
throw new IndexOutOfRangeException();
return RandomExtensions.GetRandomWeightedEntry(entries, weightFunc, random.NextSingle());
}
/// <summary>
@ -87,5 +70,32 @@ namespace MLEM.Extensions {
}
#endif
internal static T GetRandomEntry<T>(ICollection<T> entries, float randomValue) {
// ElementAt internally optimizes for IList access so we don't have to here
return entries.ElementAt((int) (randomValue * entries.Count));
}
internal static T GetRandomWeightedEntry<T>(ICollection<T> entries, Func<T, int> weightFunc, float randomValue) {
var goalWeight = randomValue * entries.Sum(weightFunc);
var currWeight = 0;
foreach (var entry in entries) {
currWeight += weightFunc(entry);
if (currWeight > goalWeight)
return entry;
}
throw new IndexOutOfRangeException();
}
internal static T GetRandomWeightedEntry<T>(ICollection<T> entries, Func<T, float> weightFunc, float randomValue) {
var goalWeight = randomValue * entries.Sum(weightFunc);
var currWeight = 0F;
foreach (var entry in entries) {
currWeight += weightFunc(entry);
if (currWeight > goalWeight)
return entry;
}
throw new IndexOutOfRangeException();
}
}
}

36
MLEM/Misc/SingleRandom.cs
View file

@ -1,4 +1,8 @@
namespace MLEM.Misc {
using System;
using System.Collections.Generic;
using MLEM.Extensions;
namespace MLEM.Misc {
/// <summary>
/// The SingleRandom class allows generating single, one-off pseudorandom numbers based on a seed or a <see cref="SeedSource"/>.
/// The types of numbers that can be generated are <see cref="int"/> and <see cref="float"/>, both of which can be generated with specific minimum and maximum values if desired.
@ -138,5 +142,35 @@
return (maxValue - minValue) * SingleRandom.Single(source) + minValue;
}
/// <summary>
/// Gets a random entry from the given collection with uniform chance.
/// </summary>
/// <param name="entries">The entries to choose from</param>
/// <param name="source">The <see cref="SeedSource"/> to use.</param>
/// <typeparam name="T">The entries' type</typeparam>
/// <returns>A random entry</returns>
public static T GetRandomEntry<T>(ICollection<T> entries, SeedSource source) {
return RandomExtensions.GetRandomEntry(entries, SingleRandom.Single(source));
}
/// <summary>
/// Returns a random entry from the given collection based on the specified weight function.
/// A higher weight for an entry increases its likeliness of being picked.
/// </summary>
/// <param name="entries">The entries to choose from</param>
/// <param name="weightFunc">A function that applies weight to each entry</param>
/// <param name="source">The <see cref="SeedSource"/> to use.</param>
/// <typeparam name="T">The entries' type</typeparam>
/// <returns>A random entry, based on the entries' weight</returns>
/// <exception cref="IndexOutOfRangeException">If the weight function returns different weights for the same entry</exception>
public static T GetRandomWeightedEntry<T>(ICollection<T> entries, Func<T, int> weightFunc, SeedSource source) {
return RandomExtensions.GetRandomWeightedEntry(entries, weightFunc, SingleRandom.Single(source));
}
/// <inheritdoc cref="GetRandomWeightedEntry{T}(System.Collections.Generic.ICollection{T},System.Func{T,int},MLEM.Misc.SeedSource)"/>
public static T GetRandomWeightedEntry<T>(ICollection<T> entries, Func<T, float> weightFunc, SeedSource source) {
return RandomExtensions.GetRandomWeightedEntry(entries, weightFunc, SingleRandom.Single(source));
}
}
}