CECCO::Trellis< T >::BCJR_Workspace Struct Reference

Workspace for BCJR forward-backward decoding. More...

#include <graphs.hpp>

Public Member Functions
	BCJR_Workspace (const Trellis &tr)
	Allocate metric arrays for tr.
void	calculate_edge_costs (const Trellis &trellis, const Matrix< double > &llrs)
	Set BCJR edge costs from symbol-level LLRs.

Public Attributes
std::vector< std::vector< double > >	alpha
	Forward metrics by layer and vertex id.
std::vector< std::vector< double > >	beta
	Backward metrics by layer and vertex id.
std::vector< std::vector< double > >	edge_costs
	Edge cost for each segment and edge index.
std::optional< std::variant< Vector< T >, Matrix< double > > >	v
	Optional received word (hard symbols or LLR matrix) shown in TikZ output.

Static Public Attributes
static constexpr bool	is_soft = true
	BCJR uses floating-point soft metrics.

Detailed Description

template<FieldType T>
struct CECCO::Trellis< T >::BCJR_Workspace

Workspace for BCJR forward-backward decoding.

Stores α and β metrics by layer and edge costs by segment. It is used by LinearCode<T>::dec_BCJR.

Definition at line 345 of file graphs.hpp.

Constructor & Destructor Documentation

BCJR_Workspace()

template<FieldType T>

CECCO::Trellis< T >::BCJR_Workspace::BCJR_Workspace ( const Trellis & tr )

explicit

Allocate metric arrays for tr.

Parameters

tr	Trellis whose layer and edge sizes define the workspace

Definition at line 643 of file graphs.hpp.

Member Function Documentation

calculate_edge_costs()

template<FieldType T>
requires FiniteFieldType<T>

void CECCO::Trellis< T >::BCJR_Workspace::calculate_edge_costs	(	const Trellis &	trellis,
		const Matrix< double > &	llrs )

Set BCJR edge costs from symbol-level LLRs.

Parameters

trellis	Trellis whose edges define candidate symbols
llrs	Symbol-level LLR matrix with q−1 rows and one column per segment

Exceptions

std::invalid_argument

if the LLR matrix has the wrong number of rows or columns

Edge costs are the symbol costs of CECCO::details::symbol_costs_from_llrs.

Definition at line 655 of file graphs.hpp.

Member Data Documentation

alpha

template<FieldType T>

std::vector<std::vector<double> > CECCO::Trellis< T >::BCJR_Workspace::alpha

Forward metrics by layer and vertex id.

Definition at line 369 of file graphs.hpp.

beta

template<FieldType T>

std::vector<std::vector<double> > CECCO::Trellis< T >::BCJR_Workspace::beta

Backward metrics by layer and vertex id.

Definition at line 371 of file graphs.hpp.

edge_costs

template<FieldType T>

std::vector<std::vector<double> > CECCO::Trellis< T >::BCJR_Workspace::edge_costs

Edge cost for each segment and edge index.

Definition at line 373 of file graphs.hpp.

is_soft

template<FieldType T>

bool CECCO::Trellis< T >::BCJR_Workspace::is_soft = true

staticconstexpr

BCJR uses floating-point soft metrics.

Definition at line 347 of file graphs.hpp.

v

template<FieldType T>

std::optional<std::variant<Vector<T>, Matrix<double> > > CECCO::Trellis< T >::BCJR_Workspace::v

Optional received word (hard symbols or LLR matrix) shown in TikZ output.

Definition at line 375 of file graphs.hpp.

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The documentation for this struct was generated from the following file:

• graphs.hpp