93 lines
3.1 KiB
Julia
93 lines
3.1 KiB
Julia
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"""
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iterates inside one partition
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"""
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mutable struct FeynmanPartitionIterator
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topology::TopologyPartition
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forest1_iterator::Union{ForestIterator,Missing}
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forest2_iterator::Union{ForestIterator,Missing}
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forest3_iterator::Union{ForestIterator,Missing}
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end
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mutable struct FeynmanDiagramTopologyIterator
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leaves::Int
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partitions_state::Vector{Int64}
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partition::FeynmanPartitionIterator
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end
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function FeynmanPartitionIterator(topology::TopologyPartition)
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return FeynmanPartitionIterator(topology, ForestIterator(topology.leaves1), ForestIterator(topology.leaves2), ForestIterator(topology.leaves3))
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end
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function FeynmanDiagramTopologyIterator(def::FeynmanDiagramDefinition)
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@assert def.n >= 4 "A Feynman diagram must have at least 4 legs"
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(p, _) = iterate(partitions(def.n))
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while length(p) != 3 || !is_valid(TopologyPartition(p[1], p[2], p[3]))
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(p, _) = iterate(partitions(def.n), p)
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end
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return FeynmanDiagramTopologyIterator(def.n, p, FeynmanPartitionIterator(TopologyPartition(p[1], p[2], p[3])))
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end
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function FeynmanDiagramTopology(iterator::FeynmanPartitionIterator)
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return FeynmanDiagramTopology(tree(iterator.forest1_iterator), tree(iterator.forest2_iterator), tree(iterator.forest3_iterator))
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end
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function FeynmanDiagramTopology(iterator::FeynmanDiagramTopologyIterator)
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return FeynmanDiagramTopology(iterator.partition)
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end
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function _iterate(iterator::FeynmanPartitionIterator)
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# todo: need symmetry breaking here
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if !is_end(iterator.forest3_iterator)
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_iterate(iterator.forest3_iterator)
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elseif !is_end(iterator.forest2_iterator)
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iterator.forest3_iterator = ForestIterator(iterator.topology.leaves3)
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_iterate(iterator.forest2_iterator)
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else
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iterator.forest3_iterator = ForestIterator(iterator.topology.leaves3)
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iterator.forest2_iterator = ForestIterator(iterator.topology.leaves2)
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_iterate(iterator.forest1_iterator)
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end
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return nothing
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end
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function _iterate(iterator::FeynmanDiagramTopologyIterator)
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if !is_end(iterator.partition)
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_iterate(iterator.partition)
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else
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while true
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ret = iterate(partitions(iterator.leaves), iterator.partitions_state)
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if (isnothing(ret))
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return false
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end
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(p, _) = ret
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iterator.partitions_state = p
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if length(p) == 3 && is_valid(TopologyPartition(p[1], p[2], p[3]))
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iterator.partition = FeynmanPartitionIterator(TopologyPartition(p[1], p[2], p[3]))
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break
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end
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end
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end
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return true
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end
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function is_end(iterator::FeynmanPartitionIterator)
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return is_end(iterator.forest1_iterator) && is_end(iterator.forest2_iterator) && is_end(iterator.forest3_iterator)
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end
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function iterate(def::FeynmanDiagramDefinition)
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state = FeynmanDiagramTopologyIterator(def)
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return (FeynmanDiagramTopology(state), state)
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end
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function iterate(def::FeynmanDiagramDefinition, state::FeynmanDiagramTopologyIterator)
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if !_iterate(state)
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return nothing
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end
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return (FeynmanDiagramTopology(state), state)
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end
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