Merge branch 'main' of https://gitlab.lisn.upsaclay.fr/fast/fst/TensorFSTs.jl

CHANGELOG.md

 # Releases
 
+## 1.4.1 - 01.03.2024
+## Fixed
+- `project_to` function was not exported
+
+## 1.4.0 - 01.03.2024
+## Added
+- Limited support of automatic differentiation
+
+## 1.3.0 - 29.02.2024
+## Added
+- Weightpushing algorithm
+
 ## 1.2.2 - 26.02.2024
 ## Fixed
 - tokenfst: is accept only sequence of 1 token.

Project.toml

 name = "TensorFSTs"
 uuid = "9f8e39db-0d6b-46cc-a14d-daf437028eec"
-authors = ["Lucas ONDEL YANG <lucas.ondel@cnrs.fr", "Cyril ALLAUZEN <allauzen@google.com", "Lukas Burget <burget@fit.vutbr.cz>", "Martin KOCOUR <ikocour@fit.vutbr.cz>", "Tina RAISSI <raissi@i6.informatik.rwth-aachen.de>", "Pablo RIERA <pablo.riera@gmail.com>", "Michael RILEY <riley@google.com>", "Jan TRMAL <yenda@jhu.edu>"]
-version = "1.2.2"
+authors = ["Lucas ONDEL YANG <lucas.ondel@cnrs.fr",
+           "Cyril ALLAUZEN <allauzen@google.com",
+           "Lukas BURGET <burget@fit.vutbr.cz>",
+           "Simon DEVAUCHELLE <devauchelle@lisn.upsaclay.fr>",
+           "Martin KOCOUR <ikocour@fit.vutbr.cz>",
+           "Tina RAISSI <raissi@i6.informatik.rwth-aachen.de>",
+           "Pablo RIERA <pablo.riera@gmail.com>",
+           "Michael RILEY <riley@google.com>",
+           "Jan TRMAL <yenda@jhu.edu>"]
+version = "1.4.1"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"
@@ -9,6 +17,6 @@ Semirings = "900aad66-9ca5-44d4-b043-321c62cb7767"
 SumSparseTensors = "472dc678-8c5a-4778-a6eb-28a4e9c7cb58"
 
 [compat]
-SumSparseTensors = "0.13"
-Semirings = "1.5"
+SumSparseTensors = "0.14"
+Semirings = "1.7"
 julia = "1.6"

src/TensorFSTs.jl

@@ -44,6 +44,9 @@ include("draw.jl")
 export
     compose,
     connect,
+    weightpush,
+    toinitial,
+    tofinal,
     closure,
     weight,
     shortestdistance,
@@ -54,6 +57,8 @@ export
 include("filter.jl")
 include("ops.jl")
 
+export project_to
+include("utils.jl")
 
 # standalone libraries
 include("../lib/LinearFSTs.jl")

src/draw.jl

@@ -72,7 +72,9 @@ function _write_dot(io::IO, fst, isyms, osyms)
     for arc in arcs(fst)
         print(io, "  ", stateid[arc.src], " -> ", stateid[arc.dest], " [label=\"")
         print(io, get(isyms, arc.isym, arc.isym), ":", get(osyms, arc.osym, arc.osym))
-        ! isone(arc.weight) ? println(io, "/", arc.weight, "\"];") : println(io, "\"];")
+        if !isone(arc.weight) print(io, "/", arc.weight) end
+        if iszero(arc.weight) print(io, "\" color=\"grey80") end
+        println(io, "\"];")
     end
 
     println(io, "}")

src/ops.jl

@@ -151,6 +151,41 @@ function connect(A::TensorFST{S}) where S
 end
 
 
+@enum FSTPush toinitial tofinal  
+
+"""
+weightpush(A, toinitial | tofinal)
+
+Returns a FST ``B`` with the weights of each path pushed as much as possible towards the initial/final states.
+"""
+function weightpush(A::TensorFST{S}, p::FSTPush) where S
+	
+	dims = dimensions(A)
+	N = length(dims.src)
+
+    nt = ntuple(identity, N)
+
+	# Shortest distance from q ∈ Q to F 
+	if p == toinitial
+		d = mulsumstar(A.M, A.ω, dims.dest, dims.src)
+        oneD = ones(S, size(d)...)
+
+        M = mul(map(inv, d), A.M, d, A.dims.src, A.dims.dest)
+		α = mul(oneD, A.α , d, nt, nt)
+		ω = mul(map(inv, d), A.ω, oneD, nt, nt)
+	# Shortest distance from I to q ∈ Q 
+	else 
+		d = mulsumstar(A.α, A.M, dims.src, dims.dest)
+        oneD = ones(S, size(d)...)
+
+        M = mul(d, A.M, map(inv, d), A.dims.src, A.dims.dest)
+		α = mul(d, A.α , oneD, nt, nt)
+		ω = mul(oneD, A.ω, map(inv, d), nt, nt)
+	end
+	TensorFST{S}(dims, M, α, ω)
+end
+
+
 @enum FSTSort state inputlabel outputlabel
 
 """
@@ -260,7 +295,7 @@ function compose(A::TensorFST{S}, B::TensorFST{S}; connect = true, flatten = con
         AF = _compose_noeps(sort(Al, state), F; connect = true)
 
         _compose_noeps(AF, sort(Bl, inputlabel); connect, flatten)
-    else
+    else        
         _compose_noeps(A, B; connect, flatten)
     end
 end

src/utils.jl

+# handy functions for gradient projections
+#
+
+import SumSparseTensors: SortedSumSparseTensor, SumSparseTensor
+
+"""
+    project_to([T=ProbSemiring], Ā, A)
+
+Project the tangent `Ā` onto input `A` (i.e. original object).
+
+The type `T` is a `Semiring` of the tangent, `ProbSemiring` by default.
+"""
+project_to(Ā, A::TensorFST{S}) where S = project_to(ProbSemiring{valtype{S}}, Ā, A)
+
+function project_to(T, Ā::NamedTuple{(:dims, :M, :α, :ω)}, A::TensorFST{S}) where S
+    TensorFST{T}(
+        dimensions(A),
+        project_to(T, Ā.M, A.M),
+        project_to(T, Ā.α, A.α),
+        project_to(T, Ā.ω, A.ω)
+    )
+end
+
+function project_to(T, ΣĀ::NamedTuple{(:axes, :nzcoo, :nzval)}, ΣA::SumSparseTensor{S,N,M}) where {S,N,M}
+    SumSparseTensor(
+        ΣA.axes,
+        ΣA.nzcoo,
+        map(t -> T(t.val), ΣĀ.nzval)
+    )
+end
+
+function project_to(T, ΣĀ::NamedTuple{(:axes, :ptr, :nzcoo, :nzval)}, ΣA::SortedSumSparseTensor{S,N,I,M}) where {S,N,I,M}
+    SortedSumSparseTensor{T,N,I}(
+        ΣA.axes,
+        ΣA.ptr,
+        ΣA.nzcoo,
+        map(t -> T(t.val), ΣĀ.nzval)
+    )
+end

test/runtests.jl

@@ -14,6 +14,23 @@ function issame(A::TensorFST, B::TensorFST)
     Set(finalweights(A)) == Set(finalweights(B)) || return false
 end
 
+function isapprox(A::TensorFST, B::TensorFST)
+    arcs_A, arcs_B = sort(arcs(A)), sort(arcs(B))
+    for (a_a, a_b) in zip(arcs_A, arcs_B)
+
+        # src, isym, osym, dest
+        if !((a_a.src == a_b.src) && (a_a.isym == a_b.isym) && (a_a.osym == a_b.osym) && (a_a.dest == a_b.dest))
+            return false
+        end
+        # Weights
+        if !(val(a_a.weight) ≈ val(a_b.weight))
+            return false
+        end
+    end
+    Set(initweights(A)) == Set(initweights(B)) || return false
+    Set(finalweights(A)) == Set(finalweights(B)) || return false
+end
+
 
 @testset "SymbolTable" begin
     _syms = Dict("a" => 1, "b" => 2)
@@ -270,6 +287,95 @@ end
     @test issame(C, compose(A, sort(B, inputlabel); connect = true))
 end
 
+@testset verbose=true "Weight-pushing" begin
+    S = TropicalSemiring{Float64}
+
+    A = TFST = TensorFST(
+        [
+            Arc(src=1, isym=1, osym=2, weight = one(S), dest=2),
+            Arc(src=1, isym=2, osym=1, weight = S(1),   dest=2),
+            Arc(src=1, isym=3, osym=2, weight = S(5),   dest=2),
+            Arc(src=1, isym=4, osym=1, weight = one(S), dest=3),
+            Arc(src=1, isym=5, osym=2, weight = S(1),   dest=3),
+            Arc(src=2, isym=5, osym=1, weight = one(S), dest=4),
+            Arc(src=2, isym=6, osym=2, weight = S(1),   dest=4),
+            Arc(src=3, isym=5, osym=1, weight = S(4),   dest=4),
+            Arc(src=3, isym=6 ,osym=2, weight = S(5),   dest=4),
+        ],
+        [(1,) => one(S)],
+        [(4,) => one(S)]
+    )
+
+    B = TFST = TensorFST(
+        [
+            Arc(src=1, isym=1, osym=2, weight = one(S), dest=2),
+            Arc(src=1, isym=2, osym=1, weight = S(1),   dest=2),
+            Arc(src=1, isym=3, osym=2, weight = S(5),   dest=2),
+            Arc(src=1, isym=4, osym=1, weight = S(4),   dest=3),
+            Arc(src=1, isym=5, osym=2, weight = S(5),   dest=3),
+            Arc(src=2, isym=5, osym=1, weight = one(S), dest=4),
+            Arc(src=2, isym=6, osym=2, weight = S(1),   dest=4),
+            Arc(src=3, isym=5, osym=1, weight = one(S), dest=4),
+            Arc(src=3, isym=6 ,osym=2, weight = S(1),   dest=4),
+        ],
+        [(1,) => one(S)],
+        [(4,) => one(S)]
+    )
+    @test issame(weightpush(A, toinitial), B)
+    @test issame(weightpush(A, tofinal), A)
+
+
+    PS = ProbSemiring{Float64}
+    C = TensorFST(
+        [
+            Arc(src=1, isym=1, osym=2, weight=zero(PS), dest=2),
+            Arc(src=1, isym=2, osym=1, weight=PS(1),    dest=2),
+            Arc(src=1, isym=3, osym=2, weight=PS(5),    dest=2),
+            Arc(src=1, isym=4, osym=1, weight=zero(PS), dest=3),
+            Arc(src=1, isym=5, osym=2, weight=PS(1),    dest=3),
+            Arc(src=2, isym=5, osym=1, weight=zero(PS), dest=4),
+            Arc(src=2, isym=6, osym=2, weight=one(PS),  dest=4),
+            Arc(src=3, isym=5, osym=1, weight=PS(4),    dest=4),
+            Arc(src=3, isym=6 ,osym=2, weight=PS(5),    dest=4),
+        ],
+        [(1,) => one(PS)],
+        [(4,) => one(PS)]
+    )
+
+    D = TensorFST(
+		[
+			Arc(src=1, isym=1, osym=2, weight=zero(PS), dest=2),
+			Arc(src=1, isym=2, osym=1, weight=PS(1/15), dest=2),
+			Arc(src=1, isym=3, osym=2, weight=PS(5/15), dest=2),
+			Arc(src=1, isym=4, osym=1, weight=zero(PS), dest=3),
+			Arc(src=1, isym=5, osym=2, weight=PS(9/15), dest=3),
+			Arc(src=2, isym=5, osym=1, weight=zero(PS), dest=4),
+			Arc(src=2, isym=6, osym=2, weight=one(PS),  dest=4),
+			Arc(src=3, isym=5, osym=1, weight=PS(4/9),  dest=4),
+			Arc(src=3, isym=6 ,osym=2, weight=PS(5/9),  dest=4),
+		],
+		[(1,) => PS(15)],
+		[(4,) => PS(1)]
+	)
+    E = TensorFST(
+        [
+            Arc(src=1, isym=1, osym=2, weight=zero(PS), dest=2),
+            Arc(src=1, isym=2, osym=1, weight=PS(1/6),  dest=2),
+            Arc(src=1, isym=3, osym=2, weight=PS(5/6),  dest=2),
+            Arc(src=1, isym=4, osym=1, weight=zero(PS), dest=3),
+            Arc(src=1, isym=5, osym=2, weight=one(PS),  dest=3),
+            Arc(src=2, isym=5, osym=1, weight=zero(PS), dest=4),
+            Arc(src=2, isym=6, osym=2, weight=PS(2/5),  dest=4),
+            Arc(src=3, isym=5, osym=1, weight=PS(4/15), dest=4),
+            Arc(src=3, isym=6 ,osym=2, weight=PS(5/15), dest=4),
+        ],
+        [(1,) => one(PS)],
+        [(4,) => PS(1/15)]
+    )
+    @test issame(weightpush(C, toinitial), D)
+    @test isapprox(weightpush(C, tofinal), E)
+end
+
 @testset verbose=true "Libaries" begin
     include("linearfsts.jl")
     include("ngramfsts.jl")