Tempo.Network.Normalize (Tempo v0.20.0)

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Reduce a Tempo.Network.t/0 to a Simple Temporal Problem: a set of boundary nodes and integer-weighted constraints of the single shape b₁ − b₂ ≤ k.

Every period contributes a start and an end boundary; a single shared origin z₀ (:origin) anchors absolute dates. The network's finest unit (the finest resolution among its dates) fixes the integer axis: a date becomes its count of that unit relative to z₀, a duration its count of that unit.

The output feeds Tempo.Network.Solver. Conversion is exact when the network is uniform-unit (as the canonical year-grained chronologies are); a duration expressed across units (e.g. years on a day axis) uses nominal calendar lengths and is rounded.

Summary

Types

boundary()
edge()

A constraint from − to ≤ weight, tagged with the source that produced it (an absolute bound, duration, sequence link, relation, or the implicit non-negativity of a period) so the solver can build a trace.

source()
t()

Functions

finest_unit(network)

The finest date resolution present in the network's period bounds.

normalize(network)

Normalise a network into %{nodes, edges, unit}.

Types

boundary()

@type boundary() :: Tempo.Network.Relation.boundary()

edge()

@type edge() :: {boundary(), boundary(), integer(), source()}

A constraint from − to ≤ weight, tagged with the source that produced it (an absolute bound, duration, sequence link, relation, or the implicit non-negativity of a period) so the solver can build a trace.

source()

@type source() ::
  {:bound, :start | :end, :lower | :upper, term(), Tempo.t()}
  | {:duration, :min | :max, term(), Tempo.Duration.t()}
  | {:non_negative, term()}
  | {:sequence, term(), term()}
  | {:relation, Tempo.Network.Relation.t()}

t()

@type t() :: %{nodes: [boundary()], edges: [edge()], unit: atom()}

Functions

finest_unit(network)

@spec finest_unit(Tempo.Network.t()) :: atom()

The finest date resolution present in the network's period bounds.

Defaults to :year when the network carries no dated bounds.

Examples

iex> Tempo.Network.new()
...> |> Tempo.Network.add_period(:a, start: "1200-06-15")
...> |> Tempo.Network.Normalize.finest_unit()
:day

normalize(network)

@spec normalize(Tempo.Network.t()) :: t()

Normalise a network into %{nodes, edges, unit}.

Arguments

Returns

  • a map with :nodes (boundary variables including :origin), :edges ({from, to, weight, source} constraints meaning from − to ≤ weight), and :unit (the axis unit atom).

Examples

iex> network =
...>   Tempo.Network.new()
...>   |> Tempo.Network.add_period(:k1, start: ~o"1200Y", duration: {:at_least, ~o"P20Y"})
iex> normalized = Tempo.Network.Normalize.normalize(network)
iex> normalized.unit
:year
iex> Enum.any?(normalized.edges, &match?({{:start, :k1}, {:end, :k1}, -20, _}, &1))
true