CGDFG also needs `findShortestPathDijkstra`

[dehann]

Prototype here:

DistributedFactorGraphs.jl/src/services/AbstractDFG.jl

Line 1055 in 4d2238f

function findShortestPathDijkstra end

LightDFG already has an implementation:

DistributedFactorGraphs.jl/src/LightDFG/services/LightDFG.jl

Lines 364 to 414 in 4d2238f

	"""
	$SIGNATURES
	Speciallized function available to only LightDFG at this time.
	Example
	```julia
	using IncrementalInference
	# canonical example graph as example
	fg = generateCanonicalFG_Kaess()
	@show path = findShortestPathDijkstra(fg, :x1, :x3)
	@show isVariable.(path)
	@show isFactor.(path)
	```
	DevNotes
	- # TODO expand to other AbstractDFG entities.
	Related
	[findFactorsBetweenNaive](@ref), `LightGraphs.dijkstra_shortest_paths`
	"""
	function findShortestPathDijkstra( dfg::LightDFG,
	from::Symbol,
	to::Symbol )
	#
	# LightDFG internally uses Integers
	frI = dfg.g.labels[from]
	toI = dfg.g.labels[to]
	path = LightGraphs.dijkstra_shortest_paths(dfg.g.graph, [toI;])
	# path = LightGraphs.enumerate_paths(path_state, toI)
	# assemble into the list
	dijkpath = Symbol[]
	# test for connectivity
	if path.dists[frI] < Inf
	cursor = frI
	push!(dijkpath, dfg.g.labels[cursor])
	# walk the path
	while cursor != toI
	cursor = path.parents[cursor]
	push!(dijkpath, dfg.g.labels[cursor])
	end
	end
	# return the list of symbols
	return dijkpath
	end