Class ChannelInfo

Describes a channel, i.e. an edge in a factor graph.

Inheritance
Object
ChannelInfo
Implements
Inherited Members
Namespace: Microsoft.ML.Probabilistic.Compiler.Transforms
Assembly: Microsoft.ML.Probabilistic.Compiler.dll
Syntax
public class ChannelInfo : ICompilerAttribute
Remarks

A channel connects a model variable to a factor. A channel is either a definition, a use, or a replicated use of a model variable.

A definition channel connects a model variable to its unique defining factor. A definition channel appears in the inference program as a program variable having the same type as the model variable.

A use channel connects a model variable to a child factor. A use channel appears in the inference program as an array of the variable type. It is indexed via [usage indices][variable indices] where the variable indices are only needed if the variable is an array.

All uses of a model variable are given the same ChannelInfo and packed into an array in the inference program. For example, if a model variable x has type double and 2 uses, its usage channels will be declared together as double[] x_uses = new double[3]; and referred to as x_uses[0] and x_uses[1].

The model variable type can be an array, in which case each channel is an array. For example, if a model variable x has type double[] and 2 uses, its usage channels will be declared together as double[][] x_uses = new double[2][]; and referred to as x_uses[0] and x_uses[1].

If the model variable is inside of a plate, then all instances of the channel share the same ChannelInfo and are packed into a nested array in the inference program. For example, if a model variable x is in a plate of size 3 and has 2 uses, its usage channels will be declared together as double[][] x_uses = new double[2][]; and x_uses[0] refers to the first use of x in the plate.

Fields

IsMarginal

Marks a channel as a marginal

Declaration
public readonly bool IsMarginal
Field Value
Type Description
Boolean

Properties

IsDef

True if the channel is a definition channel.

Declaration
public bool IsDef { get; }
Property Value
Type Description
Boolean

IsUse

True if the channel is a usage channel.

Declaration
public bool IsUse { get; }
Property Value
Type Description
Boolean

Methods

ReplaceWithUsesChannel(IExpression, IExpression)

Declaration
public IExpression ReplaceWithUsesChannel(IExpression expr, IExpression usageIndex)
Parameters
Type Name Description
IExpression expr
IExpression usageIndex
Returns
Type Description
IExpression

ToString()

Declaration
public override string ToString()
Returns
Type Description
String
Overrides

Implements