diff --git a/src/FeynmanDiagramGenerator.jl b/src/FeynmanDiagramGenerator.jl
index 2940a24..320c8b6 100644
--- a/src/FeynmanDiagramGenerator.jl
+++ b/src/FeynmanDiagramGenerator.jl
@@ -5,6 +5,8 @@ using Reexport
 @reexport using QEDcore
 @reexport using QEDprocesses
 
+using MetagraphOptimization
+
 include("QEDprocesses_patch.jl")
 
 import Base.==
@@ -45,4 +47,7 @@ include("diagrams/diagrams.jl")
 include("diagrams/iterator.jl")
 include("diagrams/QED.jl")
 
+include("metagraph_impl/compute.jl")
+include("metagraph_impl/generation.jl")
+
 end # module FeynmanDiagramGenerator
diff --git a/src/QEDprocesses_patch.jl b/src/QEDprocesses_patch.jl
index 6f7bc03..1f8be07 100644
--- a/src/QEDprocesses_patch.jl
+++ b/src/QEDprocesses_patch.jl
@@ -1,38 +1,2 @@
 # patch QEDprocesses
 # see issue https://github.com/QEDjl-project/QEDprocesses.jl/issues/77
-
-
-function _number_particles_helper(
-    particles::Tuple{}, species::SPECIES, n::Val{N}
-) where {SPECIES,N}
-    return N
-end
-
-function _number_particles_helper(
-    particles::Tuple{SPECIES,Vararg}, species::SPECIES2, n::Val{N}
-) where {SPECIES,SPECIES2,N}
-    return _number_particles_helper(particles[2:end], species, Val(N))
-end
-
-function _number_particles_helper(
-    particles::Tuple{SPECIES,Vararg}, species::SPECIES, n::Val{N}
-) where {SPECIES,N}
-    return _number_particles_helper(particles[2:end], species, Val(N + 1))
-end
-
-@inline function QEDprocesses.number_particles(
-    proc_def::AbstractProcessDefinition, dir::DIR, species::PT
-) where {DIR<:ParticleDirection,PT<:AbstractParticleType}
-    return _number_particles_helper(particles(proc_def, dir), species, Val(0))
-end
-
-"""
-    number_particles(proc_def::AbstractProcessDefinition, particle::AbstractParticleStateful)
-
-Return the number of particles of the given particle's direction and species in the given process definition.
-"""
-@inline function QEDbase.number_particles(
-    proc_def::AbstractProcessDefinition, ps::AbstractParticleStateful
-)
-    return number_particles(proc_def, particle_direction(ps), particle_species(ps))
-end
diff --git a/src/diagrams/diagrams.jl b/src/diagrams/diagrams.jl
index 1a772af..77134e6 100644
--- a/src/diagrams/diagrams.jl
+++ b/src/diagrams/diagrams.jl
@@ -469,7 +469,6 @@ function virtual_particles(proc::AbstractProcessDefinition, diagram::FeynmanDiag
     return normalize.(result)[1:end-1]
 end
 
-
 #
 # Generate Feynman Diagrams
 #
diff --git a/src/metagraph_impl/compute.jl b/src/metagraph_impl/compute.jl
new file mode 100644
index 0000000..5f362c9
--- /dev/null
+++ b/src/metagraph_impl/compute.jl
@@ -0,0 +1,38 @@
+struct ComputeTask_BaseState <: AbstractComputeTask end         # calculate the base state of an external particle
+struct ComputeTask_Propagator <: AbstractComputeTask end        # calculate the propagator term of a virtual particle
+struct ComputeTask_Pair <: AbstractComputeTask end              # from a pair of virtual particle currents, calculate the product
+struct ComputeTask_CollectPairs <: AbstractComputeTask end      # for a list of virtual particle current pair products and a propagator, sum and propagate
+struct ComputeTask_Triple <: AbstractComputeTask end            # from a triple of virtual particle currents, calculate the diagram result
+struct ComputeTask_CollectTriples <: AbstractComputeTask end    # sum over triples results and 
+
+struct BaseStateInput{PS_T<:AbstractParticleStateful,SPIN_POL_T<:AbstractSpinOrPolarization}
+    particle::PS_T
+    spin_pol::SPIN_POL_T
+end
+
+function MetagraphOptimization.compute(::ComputeTask_BaseState, input::BaseStateInput{PS,SPIN_POL}) where {PS,SPIN_POL}
+    return QEDbase.base_state(particle_species(input.particle), particle_direction(input.particle), momentum(input.particle), input.spin_pol)
+end
+
+struct PropagatorInput{VP_T<:VirtualParticle,PSP_T<:AbstractPhaseSpacePoint}
+    vp::VP_T
+    psp::PSP_T
+end
+
+function MetagraphOptimization.compute(::ComputeTask_Propagator, input::PropagatorInput{VP_T,PSP_T}) where {VP_T,PSP_T}
+    vp_mom = zero(typeof(momentum(input.psp, Incoming(), 1)))
+    for i in eachindex(in_contributions(input.vp))
+        if in_contributions(input.vp)[i]
+            vp_mom += momentum(input.psp, Incoming(), i)
+        end
+    end
+    for o in eachindex(out_contributions(input.vp))
+        if (out_contributions(input.vp))[o]
+            vp_mom -= momentum(input.psp, Outgoing(), o)
+        end
+    end
+
+    vp_species = particle_species(input.vp)
+    vp_mass = mass(vp_species)
+    return QEDbase.propagator(vp_species, vp_mom)
+end
diff --git a/src/metagraph_impl/generation.jl b/src/metagraph_impl/generation.jl
new file mode 100644
index 0000000..0c4027a
--- /dev/null
+++ b/src/metagraph_impl/generation.jl
@@ -0,0 +1,19 @@
+
+function generate_DAG(proc::GenericQEDProcess)
+    # use a set for deduplication
+    particles = Set()
+    for fd in feynman_diagrams(proc)
+        push!(all_particles, virtual_particles(proc, fd)...)
+    end
+
+    # convert to vector
+    particles = [particles...]
+
+    external_particles = _pseudo_virtual_particles(proc)
+    pairs = particle_pairs(particles)
+    triples = total_particle_triples(particles)
+
+    graph = DAG()
+
+
+end