DataStructure.md

DFG Data Structures

Variables and factors can potentially contain a lot of data, so DFG has different structures that are specialized for each use-case and level of detail. For example, if you want to retrieve just a simple summary of the structure, you can use the summary or skeleton structures to identify variables and factors of interest and then retrieve more detail on the subset.

Note that not all drivers support all of the structures.

The following section discusses the datastructures for each level. A quick summary of the types and the available properties (some of which are derived) is provided below.

Accessible properties for each of the variable structures:

	Label	Timestamp	Tags	Estimates	Soft Type	Solvable	Solver Data	Metadata	Blob Entries
VariableSkeleton	X		X
VariableSummary	X	X	X	X	Symbol				X
VariableDFG	X	X	X	X	X	X	X	X	X

Accessible properties for each of the factor structures:

	Label	Timestamp	Tags	Factor Type	Solvable	Solver Data
FactorSkeleton	X		X
FactorSummary	X	X	X
FactorCompute	X	X	X	X	X	X

DFG Skeleton types

• VariableSkeleton
• FactorSkeleton

DFG Summary types

• VariableSummary
• FactorSummary

DFG full types (solvable, portable and storeable)

• VariableDFG
• FactorDFG

Additional Offloaded Data

Additional, larger data can be associated with variables and factors using keyed blob entries.