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Showing content from http://accord-framework.net/docs/html/T_Accord_Math_Optimization_Losses_LogLikelihoodLoss.htm below:

LogLikelihoodLoss Class

Negative log-likelihood loss.

Inheritance Hierarchy

SystemObject
  Accord.Math.Optimization.LossesLogLikelihoodLoss

Namespace:  Accord.Math.Optimization.Losses
Assembly:

Accord.Math (in Accord.Math.dll) Version: 3.8.0

Syntax
[SerializableAttribute]
public class LogLikelihoodLoss : ILoss<double[][]>, 
	ILoss<double[][], double>, ILoss<double[]>, 
	ILoss<double[], double>
<SerializableAttribute>
Public Class LogLikelihoodLoss
	Implements ILoss(Of Double()()), ILoss(Of Double()(), Double), 
	ILoss(Of Double()), ILoss(Of Double(), Double)
Request Example View Source

The LogLikelihoodLoss type exposes the following members.

Constructors Methods   Name Description Equals

Determines whether the specified object is equal to the current object.

(Inherited from Object.) Finalize

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.

(Inherited from Object.) GetHashCode

Serves as the default hash function.

(Inherited from Object.) GetType

Gets the Type of the current instance.

(Inherited from Object.) Loss(Double)

Computes the loss between the expected values (ground truth) and the given actual values that have been predicted.

Loss(Double)

Computes the loss between the expected values (ground truth) and the given actual values that have been predicted.

MemberwiseClone

Creates a shallow copy of the current Object.

(Inherited from Object.) ToString

Returns a string that represents the current object.

(Inherited from Object.) Top Extension Methods   Name Description HasMethod

Checks whether an object implements a method with the given name.

(Defined by ExtensionMethods.) IsEqual

Compares two objects for equality, performing an elementwise comparison if the elements are vectors or matrices.

(Defined by Matrix.) To(Type) Overloaded.

Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.

(Defined by ExtensionMethods.) ToT Overloaded.

Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.

(Defined by ExtensionMethods.) Top Remarks

The log-likelihood loss can be used to measure the performance of unsupervised model fitting algorithms. It simply computes the sum of all log-likelihood values produced by the model.

If you would like to measure the performance of a supervised classification model based on their probability predictions, please refer to the BinaryCrossEntropyLoss and CategoryCrossEntropyLoss for binary and multi-class decision problems, respectively.

Examples

The following example shows how to learn an one-class SVM and measure its performance using the log-likelihood loss class.

Accord.Math.Random.Generator.Seed = 0;


double[][] inputs =
{
    new double[] { +1.0312479734420776  },
    new double[] { +0.99444115161895752 },
    new double[] { +0.21835240721702576 },
    new double[] { +0.47197291254997253 },
    new double[] { +0.68701112270355225 },
    new double[] { -0.58556461334228516 },
    new double[] { -0.64154046773910522 },
    new double[] { -0.66485315561294556 },
    new double[] { +0.37940266728401184 },
    new double[] { -0.61046308279037476 }
};



var teacher = new OneclassSupportVectorLearning<Linear>()
{
    Kernel = new Linear(), 
    Nu = 0.1
};


var svm = teacher.Learn(inputs);


double[] prediction = svm.Score(inputs);


double ll = new LogLikelihoodLoss().Loss(prediction);
See Also

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