public sealed class DiscreteChar : object, IDistribution<char>, ICloneable, HasPoint<char>, Diffable, SettableToUniform, CanGetLogProb<char>, SettableTo<DiscreteChar>, SettableToProduct<DiscreteChar>, SettableToProduct<DiscreteChar, DiscreteChar>, SettableToRatio<DiscreteChar>, SettableToRatio<DiscreteChar, DiscreteChar>, SettableToPower<DiscreteChar>, SettableToWeightedSumExact<DiscreteChar>, SettableToWeightedSum<DiscreteChar>, SettableToPartialUniform<DiscreteChar>, CanGetLogAverageOf<DiscreteChar>, CanGetLogAverageOfPower<DiscreteChar>, CanGetAverageLog<DiscreteChar>, CanGetMode<char>, Sampleable<char>, CanEnumerateSupport<char>

Remarks

This is an optimized version of an earlier version of this class. It doesn't use PiecewiseVector and GenericDiscreteBase<T, TThis>, tries to avoid non-inlineable calls at all costs, and assumes that the number of constant-probability character ranges is small (1-10).

Constructors

DiscreteChar()

Initializes a new instance of the DiscreteChar class by setting it to a uniform distribution.

Declaration

public DiscreteChar()

Fields

LetterCharacterRanges

Ranges of letters (for Letter()).

Declaration

public const string LetterCharacterRanges = null

Field Value

Type	Description
String

LowerCaseCharacterRanges

Ranges of lowercase characters (for Lower()).

Declaration

public const string LowerCaseCharacterRanges = null

Field Value

Type	Description
String

MixedCaseCharacterRanges

Ranges of mixed upper and lower case characters, which are merged for computational efficiency reasons.

Declaration

public const string MixedCaseCharacterRanges = null

Field Value

Type	Description
String

Remarks

In some Unicode ranges, upper and lower characters alternate which makes it very expensive to represent just lower or just upper characters using ranges. Instead, we use a loose approximation and allow characters in such ranges to be considered either lower or upper case.

This approximation means that upper and lower case character ranges are no longer mutually exclusive.

OnlyLowerCaseCharacterRanges

Ranges of only lowercase characters, excluding the mixed range.

Declaration

public const string OnlyLowerCaseCharacterRanges = null

Field Value

Type	Description
String

OnlyUpperCaseCharacterRanges

Ranges of only uppercase characters, excluding the mixed range

Declaration

public const string OnlyUpperCaseCharacterRanges = null

Field Value

Type	Description
String

UpperCaseCharacterRanges

Ranges of uppercase characters (for Upper()).

Declaration

public const string UpperCaseCharacterRanges = null

Field Value

Type	Description
String

Properties

IsDigit

Gets a value indicating whether this distribution equals the distribution created by Digit().

Declaration

public bool IsDigit { get; }

Property Value

Type	Description
Boolean

IsLetter

Gets a value indicating whether this distribution equals the distribution created by Letter().

Declaration

public bool IsLetter { get; }

Property Value

Type	Description
Boolean

IsLetterOrDigit

Gets a value indicating whether this distribution equals the distribution created by LetterOrDigit().

Declaration

public bool IsLetterOrDigit { get; }

Property Value

Type	Description
Boolean

IsLower

Gets a value indicating whether this distribution equals the distribution created by Lower().

Declaration

public bool IsLower { get; }

Property Value

Type	Description
Boolean

IsPointMass

Gets a value indicating whether this distribution represents a point mass.

Declaration

public bool IsPointMass { get; }

Property Value

Type	Description
Boolean

IsUpper

Gets a value indicating whether this distribution equals the distribution created by Upper().

Declaration

public bool IsUpper { get; }

Property Value

Type	Description
Boolean

IsWordChar

Gets a value indicating whether this distribution equals the distribution created by WordChar().

Declaration

public bool IsWordChar { get; }

Property Value

Type	Description
Boolean

Item[Char]

Gets the probability of a given character under this distribution.

Declaration

public double this[char value] { get; }

Parameters

Type	Name	Description
Char	value	The character.

Property Value

Type	Description
Double	The probability of the character under this distribution.

Point

Gets or sets the point mass represented by the distribution.

Declaration

public char Point { get; set; }

Property Value

Type	Description
Char

ProbabilityOutsideRanges

Gets the probability assigned to characters outside ranges returned by GetRanges().

Declaration

public double ProbabilityOutsideRanges { get; }

Property Value

Type	Description
Double

Methods

Any()

Creates a uniform distribution over all characters.

Declaration

public static DiscreteChar Any()

Returns

Type	Description
DiscreteChar	The created distribution.

AppendRegex(StringBuilder, Boolean)

Appends a regex expression that represents this character to the supplied string builder.

Declaration

public void AppendRegex(StringBuilder stringBuilder, bool useFriendlySymbols = false)

Parameters

Type	Name	Description
StringBuilder	stringBuilder	The string builder to append to
Boolean	useFriendlySymbols	Whether to use friendly symbols."

AppendToString(StringBuilder)

Appends the ToString() for this distribution to the supplied string builder.

Declaration

public void AppendToString(StringBuilder stringBuilder)

Parameters

Type	Name	Description
StringBuilder	stringBuilder	The string builder to append to

Clone()

Creates a copy of this distribution.

Declaration

public DiscreteChar Clone()

Returns

Type	Description
DiscreteChar	The created copy.

Complement()

Creates a distribution which is uniform over all characters that have zero probability under this distribution i.e. that are not 'in' this distribution.

Declaration

public DiscreteChar Complement()

Returns

Type	Description
DiscreteChar	The created distribution.

Remarks

This is useful for defining characters that are not in a particular distribution e.g. not a letter or not a word character.

Create(Double, IEnumerable<DiscreteChar.CharRange>)

Creates a distribution given a list of constant probability character ranges and the probability of characters outside those ranges.

Declaration

public static DiscreteChar Create(double probabilityOutsideRanges, IEnumerable<DiscreteChar.CharRange> ranges)

Parameters

Type	Name	Description
Double	probabilityOutsideRanges	The probability of characters outside the given ranges.
IEnumerable<DiscreteChar.CharRange>	ranges	The constant-probability character ranges.

Returns

Type	Description
DiscreteChar	The created distribution.

Remarks

The probabilities do not need to be normalized. The character ranges do not need to be sorted.

Digit()

Creates a uniform distribution over digits '0'..'9'.

Declaration

public static DiscreteChar Digit()

Returns

Type	Description
DiscreteChar	The created distribution.

EnumerateSupport()

Enumerates over the support of the distribution instance.

Declaration

public IEnumerable<char> EnumerateSupport()

Returns

Type	Description
IEnumerable<Char>	The character values with non-zero mass.

Equals(Object)

Checks if obj equals to this distribution (i.e. represents the same distribution over characters).

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
Object	obj	The object to compare this distribution with.

Returns

Type	Description
Boolean	true if this distribution is equal to `obj`, false otherwise.

FromVector(PiecewiseVector)

Creates a point character from a vector of (unnormalized) character probabilities.

Declaration

public static DiscreteChar FromVector(PiecewiseVector vector)

Parameters

Type	Name	Description
PiecewiseVector	vector	The vector of unnormalized probabilities.

Returns

Type	Description
DiscreteChar	The created distribution.

FromVector(Vector)

Creates a point character from a vector of (unnormalized) character probabilities.

Declaration

public static DiscreteChar FromVector(Vector vector)

Parameters

Type	Name	Description
Vector	vector	The vector of unnormalized probabilities.

Returns

Type	Description
DiscreteChar	The created distribution.

GetAverageLog(DiscreteChar)

Computes the expected logarithm of a given distribution under this distribution.

Declaration

public double GetAverageLog(DiscreteChar distribution)

Parameters

Type	Name	Description
DiscreteChar	distribution	The distribution to take the logarithm of.

Returns

Type	Description
Double	`sum_x this.Evaluate(x)*Math.Log(distribution.Evaluate(x))`

Remarks

This is also known as the cross entropy.

GetHashCode()

Gets the hash code of this distribution.

Declaration

public override int GetHashCode()

Returns

Type	Description
Int32	The hash code.

GetImpliedCharClasses(DiscreteChar.CharClasses)

Declaration

public static DiscreteChar.CharClasses GetImpliedCharClasses(DiscreteChar.CharClasses charClass)

Parameters

Type	Name	Description
DiscreteChar.CharClasses	charClass

Returns

Type	Description
DiscreteChar.CharClasses

GetLogAverageOf(DiscreteChar)

Returns the logarithm of the probability that the current distribution would draw the same sample as a given one.

Declaration

public double GetLogAverageOf(DiscreteChar distribution)

Parameters

Type	Name	Description
DiscreteChar	distribution	The given distribution.

Returns

Type	Description
Double	The logarithm of the probability that distributions would draw the same sample.

GetLogAverageOfPower(DiscreteChar, Double)

Computes the log-integral of one distribution times another raised to a power.

Declaration

public double GetLogAverageOfPower(DiscreteChar distribution, double power)

Parameters

Type	Name	Description
DiscreteChar	distribution	The other distribution
Double	power	The power.

Returns

Type	Description
Double	`Math.Log(sum_x this.Evaluate(x) * Math.Pow(distribution.Evaluate(x), power))`

Remarks

This is not the same as GetLogAverageOf(distribution^power) because it includes the normalization constant of that.

GetLogProb(Char)

Gets the logarithm of the probability of a given character under this distribution.

Declaration

public double GetLogProb(char value)

Parameters

Type	Name	Description
Char	value	The character.

Returns

Type	Description
Double	true if this distribution is a uniform distribution over all possible characters, false otherwise.

GetMode()

Gets the mode of this distribution.

Declaration

public char GetMode()

Returns

Type	Description
Char	The mode.

GetProbs()

Gets a vector of character probabilities under this distribution.

Declaration

public PiecewiseVector GetProbs()

Returns

Type	Description
PiecewiseVector	A vector of character probabilities.

GetRanges()

Gets an array of character ranges with associated probabilities.

Declaration

public DiscreteChar.CharRange[] GetRanges()

Returns

Type	Description
DiscreteChar.CharRange[]	An array of character ranges with associated probabilities.

Remarks

See ProbabilityOutsideRanges for the probability of characters not covered by the returned ranges.

InRange(Char, Char)

Creates a uniform distribution over characters in a given range.

Declaration

public static DiscreteChar InRange(char start, char end)

Parameters

Type	Name	Description
Char	start	The start of the range (inclusive).
Char	end	The end of the range (inclusive).

Returns

Type	Description
DiscreteChar	The created distribution.

InRanges(IEnumerable<Char>)

Creates a distribution which is uniform over values in multiple ranges specified by pairs of start and end values. These pairs are specified as adjacent values in a sequence whose length must therefore be even.

Declaration

public static DiscreteChar InRanges(IEnumerable<char> startEndPairs)

Parameters

Type	Name	Description
IEnumerable<Char>	startEndPairs	The sequence of range starts and ends.

Returns

Type	Description
DiscreteChar	The created distribution.

InRanges(Char[])

Creates a distribution which is uniform over values in multiple ranges specified by pairs of start and end values. These pairs are specified as adjacent values in an array whose length must therefore be even.

Declaration

public static DiscreteChar InRanges(params char[] startEndPairs)

Parameters

Type	Name	Description
Char[]	startEndPairs	The array of range starts and ends.

Returns

Type	Description
DiscreteChar	The created distribution.

IsPartialUniform()

Checks whether the distribution is uniform over its support.

Declaration

public bool IsPartialUniform()

Returns

Type	Description
Boolean	true if the distribution is uniform over its support, false otherwise.

IsUniform()

Checks whether this distribution is a uniform distribution over all characters.

Declaration

public bool IsUniform()

Returns

Type	Description
Boolean	true if this distribution is a uniform distribution over all possible characters, false otherwise.

Letter()

Creates a uniform distribution over letters.

Declaration

public static DiscreteChar Letter()

Returns

Type	Description
DiscreteChar	The created distribution.

LetterOrDigit()

Creates a uniform distribution over letters and '0'..'9'.

Declaration

public static DiscreteChar LetterOrDigit()

Returns

Type	Description
DiscreteChar	The created distribution.

Lower()

Creates a uniform distribution over lowercase letters.

Declaration

public static DiscreteChar Lower()

Returns

Type	Description
DiscreteChar	The created distribution.

MaxDiff(Object)

Gets the maximum difference between the character probabilities under this distribution and a given one.

Declaration

public double MaxDiff(object distribution)

Parameters

Type	Name	Description
Object	distribution	The distribution to compute the maximum probability difference with.

Returns

Type	Description
Double	The computed maximum probability difference.

NonWordChar()

Creates a uniform distribution over all characters except (letter, digit and '_').

Declaration

public static DiscreteChar NonWordChar()

Returns

Type	Description
DiscreteChar	The created distribution.

OneOf(IEnumerable<Char>)

Creates a distribution which is uniform over the specified set of characters.

Declaration

public static DiscreteChar OneOf(IEnumerable<char> chars)

Parameters

Type	Name	Description
IEnumerable<Char>	chars	The characters.

Returns

Type	Description
DiscreteChar	The created distribution.

OneOf(Char[])

Creates a distribution which is uniform over the specified set of characters.

Declaration

public static DiscreteChar OneOf(params char[] chars)

Parameters

Type	Name	Description
Char[]	chars	The characters.

Returns

Type	Description
DiscreteChar	The created distribution.

PointMass(Char)

Creates a point mass character distribution.

Declaration

public static DiscreteChar PointMass(char point)

Parameters

Type	Name	Description
Char	point	The point.

Returns

Type	Description
DiscreteChar	The created distribution.

Read(Func<Int32>, Func<Double>)

Reads a discrete character.

Declaration

public static DiscreteChar Read(Func<int> readInt32, Func<double> readDouble)

Parameters

Type	Name	Description
Func<Int32>	readInt32
Func<Double>	readDouble

Returns

Type	Description
DiscreteChar

Sample()

Draws a sample from the distribution.

Declaration

public char Sample()

Returns

Type	Description
Char	The drawn sample.

Sample(Char)

Draws a sample from the distribution.

Declaration

public char Sample(char result)

Parameters

Type	Name	Description
Char	result	A pre-allocated storage for the sample (will be ignored).

Returns

Type	Description
Char	The drawn sample.

SetTo(DiscreteChar)

Sets this distribution to be equal to a given distribution.

Declaration

public void SetTo(DiscreteChar distribution)

Parameters

Type	Name	Description
DiscreteChar	distribution	The distribution to set this distribution to.

SetToPartialUniform()

Sets the distribution to be uniform over its support.

Declaration

public void SetToPartialUniform()

SetToPartialUniformOf(DiscreteChar)

Sets the distribution to be uniform over the support of a given distribution.

Declaration

public void SetToPartialUniformOf(DiscreteChar distribution)

Parameters

Type	Name	Description
DiscreteChar	distribution	The distribution which support will be used to setup the current distribution.

SetToPower(DiscreteChar, Double)

Sets the current distribution to a given distribution raised to a given power.

Declaration

public void SetToPower(DiscreteChar distribution, double power)

Parameters

Type	Name	Description
DiscreteChar	distribution	The distribution to raise to the power.
Double	power	The power.

SetToProduct(DiscreteChar, DiscreteChar)

Sets this distribution to a product of a given pair of distributions.

Declaration

public void SetToProduct(DiscreteChar distribution1, DiscreteChar distribution2)

Parameters

Type	Name	Description
DiscreteChar	distribution1	The first distribution.
DiscreteChar	distribution2	The second distribution.

SetToRatio(DiscreteChar, DiscreteChar, Boolean)

Sets the current distribution to the ratio of a given pair of distributions.

Declaration

public void SetToRatio(DiscreteChar numerator, DiscreteChar denominator, bool forceProper = false)

Parameters

Type	Name	Description
DiscreteChar	numerator	The numerator in the ratio.
DiscreteChar	denominator	The denominator in the ratio.
Boolean	forceProper	Specifies whether the ratio must be proper.

SetToSum(Double, DiscreteChar, Double, DiscreteChar)

Sets this distribution to a weighted sum of a given pair of distributions.

Declaration

public void SetToSum(double weight1, DiscreteChar distribution1, double weight2, DiscreteChar distribution2)

Parameters

Type	Name	Description
Double	weight1	The weight of the first distribution.
DiscreteChar	distribution1	The first distribution.
Double	weight2	The weight of the second distribution.
DiscreteChar	distribution2	The second distribution.

SetToUniform()

Sets this distribution to a uniform distribution over all characters.

Declaration

public void SetToUniform()

SwapWith(DiscreteChar)

Swaps this distribution with a given one.

Declaration

public void SwapWith(DiscreteChar distribution)

Parameters

Type	Name	Description
DiscreteChar	distribution	The distribution to swap this distribution with.

ToLower(DiscreteChar)

Declaration

public static DiscreteChar ToLower(DiscreteChar unnormalizedCharDist)

Parameters

Type	Name	Description
DiscreteChar	unnormalizedCharDist

Returns

Type	Description
DiscreteChar

ToString()

Gets a string that represents this distribution.

Declaration

public override string ToString()

Returns

Type	Description
String	A string that represents this distribution.

Uniform()

Creates a uniform distribution over characters.

Declaration

public static DiscreteChar Uniform()

Returns

Type	Description
DiscreteChar	The created distribution.

UniformInRange(Char, Char)

Creates a uniform distribution over characters in a given range.

Declaration

public static DiscreteChar UniformInRange(char start, char end)

Parameters

Type	Name	Description
Char	start	The start of the range (inclusive).
Char	end	The end of the range (inclusive).

Returns

Type	Description
DiscreteChar	The created distribution.

UniformInRanges(IEnumerable<Char>)

Declaration

public static DiscreteChar UniformInRanges(IEnumerable<char> startEndPairs)

Parameters

Type	Name	Description
IEnumerable<Char>	startEndPairs	The sequence of range starts and ends.

Returns

Type	Description
DiscreteChar	The created distribution.

UniformInRanges(Char[])

Declaration

public static DiscreteChar UniformInRanges(params char[] startEndPairs)

Parameters

Type	Name	Description
Char[]	startEndPairs	The array of range starts and ends.

Returns

Type	Description
DiscreteChar	The created distribution.

UniformOver(IEnumerable<Char>)

Creates a distribution which is uniform over the specified set of characters.

Declaration

public static DiscreteChar UniformOver(IEnumerable<char> chars)

Parameters

Type	Name	Description
IEnumerable<Char>	chars	The characters.

Returns

Type	Description
DiscreteChar	The created distribution.

UniformOver(Char[])

Creates a distribution which is uniform over the specified set of characters.

Declaration

public static DiscreteChar UniformOver(params char[] chars)

Parameters

Type	Name	Description
Char[]	chars	The characters.

Returns

Type	Description
DiscreteChar	The created distribution.

Upper()

Creates a uniform distribution over uppercase letters.

Declaration

public static DiscreteChar Upper()

Returns

Type	Description
DiscreteChar	The created distribution.

Whitespace()

Creates a uniform distribution over whitespace characters ('\t'..'\r', ' ').

Declaration

public static DiscreteChar Whitespace()

Returns

Type	Description
DiscreteChar	The created distribution.

WordChar()

Creates a uniform distribution over word characters (letter, digit and '_').

Declaration

public static DiscreteChar WordChar()

Returns

Type	Description
DiscreteChar	The created distribution.

Write(Action<Int32>, Action<Double>)

Writes a discrete character.

Declaration

public void Write(Action<int> writeInt32, Action<double> writeDouble)

Parameters

Type	Name	Description
Action<Int32>	writeInt32
Action<Double>	writeDouble

Implements

IDistribution<T>

ICloneable

HasPoint<T>

Diffable

SettableToUniform

CanGetLogProb<T>

SettableTo<T>

SettableToProduct<T>

SettableToProduct<T, U>

SettableToRatio<T>

SettableToRatio<T, U>

SettableToPower<T>

SettableToWeightedSumExact<T>

SettableToWeightedSum<T>

SettableToPartialUniform<TDist>

CanGetLogAverageOf<T>

CanGetLogAverageOfPower<T>

CanGetAverageLog<T>

CanGetMode<ModeType>

Sampleable<T>

CanEnumerateSupport<T>