port ProblemReductions

QuEraComputing · Nov 27, 2024 · 6db3c3c · 6db3c3c
1 parent c59325e
commit 6db3c3c
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Showing 3 changed files with 68 additions and 14 deletions.
diff --git a/src/dragondrop.jl b/src/dragondrop.jl
@@ -335,7 +335,7 @@ function post_process_grid(grid::Matrix{SimpleCell{T}}, h0, h1) where T
     return gg, pins
 end
 
-struct QUBOResult{NT}
+struct QUBOResult{NT} <: ProblemReductions.AbstractReductionResult
     grid_graph::GridGraph{NT}
     pins::Vector{Int}
     mis_overhead::Int
@@ -353,13 +353,13 @@ function map_config_back(res::WMISResult, cfg)
     return cfg[res.pins]
 end
 
-struct RestrictedQUBOResult{NT}
+struct RestrictedQUBOResult{NT} <: ProblemReductions.AbstractReductionResult
     grid_graph::GridGraph{NT}
 end
 function map_config_back(res::RestrictedQUBOResult, cfg)
 end
 
-struct SquareQUBOResult{NT}
+struct SquareQUBOResult{NT} <: ProblemReductions.AbstractReductionResult
     grid_graph::GridGraph{NT}
     pins::Vector{Int}
     mis_overhead::Float64

diff --git a/src/reduceto.jl b/src/reduceto.jl
@@ -3,14 +3,14 @@ struct IndependentSetToKSG{NT, VT} <: ProblemReductions.AbstractReductionResult
     weights::VT
 end
 function _to_gridgraph(g::UnitDiskMapping.GridGraph)
-    return ProblemReductions.GridGraph(g.size, getfield.(g.nodes, :loc), g.radius)
+    return ProblemReductions.GridGraph(getfield.(g.nodes, :loc), g.radius)
 end
 function _extract_weights(g::UnitDiskMapping.GridGraph{<:WeightedNode})
     getfield.(g.nodes, :weight)
 end
 
 ###### unweighted reduction
-function ProblemReductions.reduceto(::Type{ProblemReductions.IndependentSet{ProblemReductions.GridGraph, Int, ProblemReductions.UnitWeight}}, problem::ProblemReductions.IndependentSet{GT, Int, ProblemReductions.UnitWeight} where GT<:SimpleGraph)
+function ProblemReductions.reduceto(::Type{ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Int, ProblemReductions.UnitWeight}}, problem::ProblemReductions.IndependentSet{GT, Int, ProblemReductions.UnitWeight} where GT<:SimpleGraph)
     return IndependentSetToKSG(map_graph(UnWeighted(), problem.graph), problem.weights)
 end
 
@@ -23,7 +23,7 @@ end
 
 ###### Weighted reduction
 # TODO: rescale the weights to avoid errors
-function ProblemReductions.reduceto(::Type{ProblemReductions.IndependentSet{ProblemReductions.GridGraph, T, Vector{T}}} where T, problem::ProblemReductions.IndependentSet{GT} where GT<:SimpleGraph)
+function ProblemReductions.reduceto(::Type{ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, T, Vector{T}}} where T, problem::ProblemReductions.IndependentSet{GT} where GT<:SimpleGraph)
     return IndependentSetToKSG(map_graph(Weighted(), problem.graph), problem.weights)
 end
 function ProblemReductions.target_problem(res::IndependentSetToKSG{<:WeightedNode})
@@ -35,12 +35,12 @@ end
 ###### Factoring ######
 struct FactoringToIndependentSet{NT} <: ProblemReductions.AbstractReductionResult
     mapres::FactoringResult{NT}
-    raw_graph::ProblemReductions.GridGraph
+    raw_graph::ProblemReductions.GridGraph{2}
     raw_weight::Vector{Int}
     vmap::Vector{Int}
-    problem::ProblemReductions.IndependentSet{ProblemReductions.GridGraph, Int, Vector{Int}}
+    problem::ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Int, Vector{Int}}
 end
-function ProblemReductions.reduceto(::Type{ProblemReductions.IndependentSet{ProblemReductions.GridGraph, T, Vector{T}}} where T, problem::ProblemReductions.Factoring)
+function ProblemReductions.reduceto(::Type{ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, T, Vector{T}}} where T, problem::ProblemReductions.Factoring)
     mres = map_factoring(problem.m, problem.n)
     g = _to_gridgraph(mres.grid_graph)
     ws = getfield.(mres.grid_graph.nodes, :weight)
@@ -57,4 +57,50 @@ function ProblemReductions.extract_solution(res::FactoringToIndependentSet, sol)
     cfg[res.vmap] .= sol
     i1, i2 = map_config_back(res.mapres, cfg)
     return vcat([i1>>(k-1) & 1 for k=1:length(res.mapres.pins_input1)], [i2>>(k-1) & 1 for k=1:length(res.mapres.pins_input2)])
-end
+end
+
+###### Spinglass problem to MIS on KSG ######
+# NOTE: I am not sure about the correctness of this reduction. If you encounter a bug, please question this function!
+function ProblemReductions.reduceto(::Type{ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, T, Vector{T}}} where T, problem::ProblemReductions.SpinGlass{<:SimpleGraph})
+    n = length(problem.h)
+    M = similar(problem.h, n, n)
+    for (e, j) in zip(edges(problem.graph), problem.J)
+        M[e.src, e.dst] = M[e.dst, e.src] = j
+    end
+    return map_qubo(M, -problem.h)
+end
+
+function ProblemReductions.target_problem(res::QUBOResult)
+    grid = _to_gridgraph(res.grid_graph)
+    ws = getfield.(res.grid_graph.nodes, :weight)
+    return ProblemReductions.IndependentSet(grid, ws)
+end
+
+function ProblemReductions.extract_solution(res::QUBOResult, sol)
+    res = map_config_back(res, sol)
+    return 1 .- 2 .* Int.(res)
+end
+
+###### Spinglass problem on grid to MIS on KSG ######
+# NOTE: the restricted layout is not implemented, since it is not often used
+function ProblemReductions.reduceto(::Type{ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, T, Vector{T}}} where T, problem::ProblemReductions.SpinGlass{ProblemReductions.GridGraph{2}})
+    g = problem.graph
+    @assert 1 <= g.radius < sqrt(2) "Only support nearest neighbor interaction"
+    coupling = [(g.locations[e.src]..., g.locations[e.dst]..., J) for (e, J) in zip(edges(g), problem.J)]
+    onsite = [(i, j, -h) for ((i, j), h) in zip(g.locations, problem.h)]
+    # a vector coupling of `(i, j, i', j', J)`, s.t. (i', j') == (i, j+1) or (i', j') = (i+1, j).
+    # a vector of onsite term `(i, j, h)`.
+    return map_qubo_square(coupling, onsite)
+end
+
+function ProblemReductions.target_problem(res::SquareQUBOResult)
+    grid = _to_gridgraph(res.grid_graph)
+    ws = getfield.(res.grid_graph.nodes, :weight)
+    return ProblemReductions.IndependentSet(grid, ws)
+end
+
+function ProblemReductions.extract_solution(res::SquareQUBOResult, sol)
+    res = map_config_back(res, sol)
+    return 1 .- 2 .* Int.(res)
+end
+
diff --git a/test/reduceto.jl b/test/reduceto.jl
@@ -6,11 +6,19 @@ import ProblemReductions
     fact = ProblemReductions.Factoring(2, 1, 2)
     is = ProblemReductions.IndependentSet(graph)
     wis = ProblemReductions.IndependentSet(graph, rand(nv(graph)) .* 0.2)
+    sg = ProblemReductions.SpinGlass(graph, [0.2, 0.4, -0.6], [0.1, 0.1, 0.1])
+    sg2 = ProblemReductions.SpinGlass(graph, [0.1, 0.1, -0.1], [0.1, 0.1, 0.1])
+    grid = ProblemReductions.GridGraph(ones(Bool, 2, 2), 1.2)
+    sg_square = ProblemReductions.SpinGlass(grid, [0.1, 0.3, -0.1, 0.4], [0.1, 0.1, 0.1, 0.2])
+    sg_square2 = ProblemReductions.SpinGlass(grid, [0.1, -0.3, 0.1, 0.4], [0.1, 0.1, 0.1, 0.2])
     for (source, target_type) in [
-            # please add more tests here
-            is => ProblemReductions.IndependentSet{ProblemReductions.GridGraph, Int, ProblemReductions.UnitWeight},
-            wis => ProblemReductions.IndependentSet{ProblemReductions.GridGraph, Float64, Vector{Float64}},
-            fact => ProblemReductions.IndependentSet{ProblemReductions.GridGraph, Int, Vector{Int}},
+            sg_square => ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Float64, Vector{Float64}},
+            sg_square2 => ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Float64, Vector{Float64}},
+            sg => ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Float64, Vector{Float64}},
+            sg2 => ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Float64, Vector{Float64}},
+            is => ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Int, ProblemReductions.UnitWeight},
+            wis => ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Float64, Vector{Float64}},
+            fact => ProblemReductions.IndependentSet{ProblemReductions.GridGraph{2}, Int, Vector{Int}},
         ]
         @info "Testing reduction from $(typeof(source)) to $(target_type)"
         # directly solve