Merge EdgeSelected constraint into resp. variable

docs/source/api.rst

@@ -156,11 +156,3 @@ Pin
 ^^^
   .. autoclass:: Pin
      :show-inheritance:
-
-SelectEdgeNodes (internal use)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  .. autoclass:: SelectEdgeNodes
-     :show-inheritance:
-
-
-

motile/constraints/__init__.py

@@ -4,7 +4,6 @@
 from .max_children import MaxChildren
 from .max_parents import MaxParents
 from .pin import Pin
-from .select_edge_nodes import SelectEdgeNodes
 
 __all__ = [
     "Constraint",
@@ -13,5 +12,4 @@
     "MaxChildren",
     "MaxParents",
     "Pin",
-    "SelectEdgeNodes",
 ]

motile/solver.py

@@ -7,7 +7,6 @@
 import ilpy
 import numpy as np
 
-from .constraints import SelectEdgeNodes
 from .constraints.constraint import Constraint
 from .costs import Features, Weight, Weights
 from .ssvm import fit_weights
@@ -28,16 +27,9 @@ class Solver:
     Args:
         track_graph:
             The :class:`~motile.TrackGraph` of objects to track over time.
-
-        skip_core_constraints (:obj:`bool`, default=False):
-            If true, add no constraints to the solver at all. Otherwise, core
-            constraints that ensure consistencies between selected nodes and
-            edges are added.
     """
 
-    def __init__(
-        self, track_graph: TrackGraph, skip_core_constraints: bool = False
-    ) -> None:
+    def __init__(self, track_graph: TrackGraph) -> None:
         if not isinstance(track_graph, TrackGraph):
             import networkx as nx
 
@@ -70,9 +62,6 @@ def __init__(
         self._cost_instances: dict[str, Cost] = {}
         self.solution: ilpy.Solution | None = None
 
-        if not skip_core_constraints:
-            self.add_constraint(SelectEdgeNodes())
-
     def add_cost(self, cost: Cost, name: str | None = None) -> None:
         """Add linear cost to the value of variables in this solver.
 

motile/variables/edge_selected.py

@@ -1,10 +1,13 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Collection
+from typing import TYPE_CHECKING, Collection, Iterable
 
+from .node_selected import NodeSelected
 from .variable import Variable
 
 if TYPE_CHECKING:
+    import ilpy
+
     from motile._types import EdgeId
     from motile.solver import Solver
 
@@ -15,3 +18,13 @@ class EdgeSelected(Variable["EdgeId"]):
     @staticmethod
     def instantiate(solver: Solver) -> Collection[EdgeId]:
         return solver.graph.edges
+
+    @staticmethod
+    def instantiate_constraints(solver: Solver) -> Iterable[ilpy.Expression]:
+        node_indicators = solver.get_variables(NodeSelected)
+        edge_indicators = solver.get_variables(EdgeSelected)
+
+        for edge in solver.graph.edges:
+            nodes = list(solver.graph.nodes_of(edge))
+            x_e = edge_indicators[edge]
+            yield len(nodes) * x_e - sum(node_indicators[n] for n in nodes) <= 0