This file contains class definitions for classes ForwardingDescriptor, SumDescriptor and Descriptor. More...

#include "base/kaldi-common.h"
#include "util/kaldi-io.h"
#include "matrix/matrix-lib.h"
#include "nnet3/nnet-common.h"
#include "nnet3/nnet-component-itf.h"
#include <iostream>
#include <sstream>
#include <vector>
#include <map>

Include dependency graph for nnet-descriptor.h:

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Classes
class	ForwardingDescriptor
	A ForwardingDescriptor describes how we copy data from another NetworkNode, or from multiple other NetworkNodes, possibly with a scalar weight. More...

class	SimpleForwardingDescriptor
	SimpleForwardingDescriptor is the base-case of ForwardingDescriptor, consisting of a source node in the graph with a given scalar weight (which will in the normal case be 1.0). More...

class	OffsetForwardingDescriptor
	Offsets in 't' and 'x' values of other ForwardingDescriptors. More...

class	SwitchingForwardingDescriptor
	Chooses from different inputs based on the the time index modulo (the number of ForwardingDescriptors given as inputs). More...

class	RoundingForwardingDescriptor
	For use in clockwork RNNs and the like, this forwarding-descriptor rounds the time-index t down to the the closest t' <= t that is an exact multiple of t_modulus_. More...

class	ReplaceIndexForwardingDescriptor
	This ForwardingDescriptor modifies the indexes (n, t, x) by replacing one of them (normally t) with a constant value and keeping the rest. More...

class	SumDescriptor
	This is an abstract base-class. More...

class	OptionalSumDescriptor
	This is the case of class SumDescriptor, in which we contain just one term, and that term is optional (an IfDefined() expression). More...

class	SimpleSumDescriptor
	This is the normal base-case of SumDescriptor which just wraps a ForwardingDescriptor. More...

class	ConstantSumDescriptor
	This is an alternative base-case of SumDescriptor (an alternative to SimpleSumDescriptor) which represents a constant term, e.g. More...

class	BinarySumDescriptor
	BinarySumDescriptor can represent either A + B, or (A if defined, else B). More...

class	Descriptor

struct	GeneralDescriptor
	This class is only used when parsing Descriptors. More...

Namespaces
	kaldi
	This code computes Goodness of Pronunciation (GOP) and extracts phone-level pronunciation feature for mispronunciations detection tasks, the reference:

	kaldi::nnet3

Detailed Description

This file contains class definitions for classes ForwardingDescriptor, SumDescriptor and Descriptor.

Basically this is code that specifies how we glue together the outputs of possibly several other network-nodes, as the input of a particular network node (or as an output of the network). In the neural-network code we refer to the top-level descriptor which is Descriptor. The InputDescriptor is a concatenation of features; each part is a SumDescriptor. The SumDescriptor is a summation over a set of features of all the same dimension, each of which is represented by a ForwardingDescriptor. A ForwardingDescriptor in the simplest case just takes just points you to a particular network node, but in general can do things like adding time offsets, and selecting different rows of its matrix from different inputs. Unlike the other descriptors, a ForwardingDescriptor is in general a bit like a parse tree, in that it can in general contain other ForwardingDescriptors.

The following gives an overview of the expressions that can appear in descriptors. Caution; this is a simplification that overgenerates descriptors: not all combinations are allowed.

<descriptor>  ::=   <node-name>      ;; node name of kInput or kComponent node.
<descriptor>  ::=   Append(<descriptor>, <descriptor> [, <descriptor> ... ] )
<descriptor>  ::=   Sum(<descriptor>, <descriptor>)
<descriptor>  ::=   Const(<value>, <dimension>)    ;; e.g. Const(1.0, 512)
<descriptor>  ::=   Scale(<scale>, <descriptor>)   ;; e.g. Scale(-1.0, tdnn2)
;; Failover or IfDefined might be useful for time t=-1 in a RNN, for instance.
<descriptor>  ::=   Failover(<descriptor>, <descriptor>)   ;; 1st arg if computable, else 2nd
<descriptor>  ::=   IfDefined(<descriptor>)     ;; the arg if defined, else zero.
<descriptor>  ::=   Offset(<descriptor>, <t-offset> [, <x-offset> ] ) ;; offsets are integers
;; Switch(...) is intended to be used in clockwork RNNs or similar schemes.  It chooses
;; one argument based on the value of t (in the requested Index) modulo the number of
;; arguments
<descriptor>  ::=   Switch(<descriptor>, <descriptor> [, <descriptor> ...])
;; For use in clockwork RNNs or similar, Round() rounds the time-index t of the
;; requested Index to the next-lowest multiple of the integer <t-modulus>,
;; and evaluates the input argument for the resulting Index.
<descriptor>  ::=   Round(<descriptor>, <t-modulus>)  ;; <t-modulus> is an integer
;; ReplaceIndex replaces some <variable-name> (t or x) in the requested Index
;; with a fixed integer <value>.  E.g. might be useful when incorporating
;; iVectors; iVector would always have time-index t=0.
<descriptor>  ::=   ReplaceIndex(<descriptor>, <variable-name>, <value>)

Definition in file nnet-descriptor.h.

Classes

Namespaces

Detailed Description