100 unify cost api

motile/costs/appear.py

@@ -17,18 +17,20 @@ class Appear(Cost):
 
     Args:
         weight:
-            The weight to apply to the cost of each starting track.
+            The weight to apply to the cost attribute of each starting track.
+            Defaults to 1.
 
         attribute:
             The name of the attribute to use to look up cost. Default is
             ``None``, which means that a constant cost is used.
 
         constant:
-            A constant cost for each node that starts a track.
+            A constant cost for each node that starts a track. Defaults to 0.
 
         ignore_attribute:
             The name of an optional node attribute that, if it is set and
             evaluates to ``True``, will not set the appear cost for that node.
+            Defaults to None
     """
 
     def __init__(

motile/costs/disappear.py

@@ -16,17 +16,32 @@
     This is cost is not applied to nodes in the last frame of the graph.
 
     Args:
-        constant (float):
-            A constant cost for each node that ends a track.
+        weight:
+            The weight to apply to the cost of each ending track. Defaults to 1.
+
+        attribute:
+            The name of the attribute to use to look up cost. Default is
+            ``None``, which means that a constant cost is used.
+
+        constant:
+            A constant cost for each node that starts a track. Defaults to 0.
 
         ignore_attribute:
             The name of an optional node attribute that, if it is set and
-            evaluates to ``True``, will not set the disappear cost for that
-            node.
+            evaluates to ``True``, will not set the disappear cost for that node.
+            Defaults to None.
     """
 
-    def __init__(self, constant: float, ignore_attribute: str | None = None) -> None:
+    def __init__(
+        self,
+        weight: float = 1,
+        attribute: str | None = None,
+        constant: float = 0,
+        ignore_attribute: str | None = None,
+    ):
+        self.weight = Weight(weight)
         self.constant = Weight(constant)
+        self.attribute = attribute
         self.ignore_attribute = ignore_attribute
 
     def apply(self, solver: Solver) -> None:
@@ -39,4 +54,8 @@
                     continue
             if G.nodes[node][G.frame_attribute] == G.get_frames()[1] - 1:
                 continue
+            if self.attribute is not None:
+                solver.add_variable_cost(
+                    index, G.nodes[node][self.attribute], self.weight
+                )
             solver.add_variable_cost(index, 1.0, self.constant)

motile/costs/edge_selection.py

@@ -15,19 +15,19 @@ class EdgeSelection(Cost):
 
     Args:
         weight:
-            The weight to apply to the cost given by the ``cost`` attribute of
-            each edge.
+            The weight to apply to the cost given by the provided attribute of
+            each edge. Default is ``1.0``.
 
         attribute:
             The name of the edge attribute to use to look up cost. Default is
-            ``'cost'``.
+            None, which means only a constant cost is used.
 
         constant:
             A constant cost for each selected edge. Default is ``0.0``.
     """
 
     def __init__(
-        self, weight: float, attribute: str = "cost", constant: float = 0.0
+        self, weight: float = 1, attribute: str | None = None, constant: float = 0.0
     ) -> None:
         self.weight = Weight(weight)
         self.constant = Weight(constant)
@@ -37,7 +37,8 @@ def apply(self, solver: Solver) -> None:
         edge_variables = solver.get_variables(EdgeSelected)
 
         for edge, index in edge_variables.items():
-            solver.add_variable_cost(
-                index, solver.graph.edges[edge][self.attribute], self.weight
-            )
+            if self.attribute is not None:
+                solver.add_variable_cost(
+                    index, solver.graph.edges[edge][self.attribute], self.weight
+                )
             solver.add_variable_cost(index, 1.0, self.constant)

motile/costs/node_selection.py

@@ -15,19 +15,19 @@ class NodeSelection(Cost):
 
     Args:
         weight:
-            The weight to apply to the cost given by the ``cost`` attribute of
-            each node.
+            The weight to apply to the cost given by the provided attribute of
+            each node. Default is ``1.0``
 
         attribute:
-            The name of the node attribute to use to look up cost. Default is
-            ``'cost'``.
+            The name of the node attribute to use to look up cost, or None if a constant
+            cost is desired. Default is ``None``.
 
         constant:
             A constant cost for each selected node. Default is ``0.0``.
     """
 
     def __init__(
-        self, weight: float, attribute: str = "cost", constant: float = 0.0
+        self, weight: float = 1, attribute: str | None = None, constant: float = 0.0
     ) -> None:
         self.weight = Weight(weight)
         self.constant = Weight(constant)
@@ -37,7 +37,8 @@ def apply(self, solver: Solver) -> None:
         node_variables = solver.get_variables(NodeSelected)
 
         for node, index in node_variables.items():
-            solver.add_variable_cost(
-                index, solver.graph.nodes[node][self.attribute], self.weight
-            )
+            if self.attribute is not None:
+                solver.add_variable_cost(
+                    index, solver.graph.nodes[node][self.attribute], self.weight
+                )
             solver.add_variable_cost(index, 1.0, self.constant)

motile/costs/split.py

@@ -15,15 +15,15 @@ class Split(Cost):
 
     Args:
         weight:
-            The weight to apply to the cost of each split.
+            The weight to apply to the cost of each split. Default is ``1``.
 
         attribute:
             The name of the attribute to use to look up the cost. Default is
             ``None``, which means that a constant cost is used.
 
         constant:
             A constant cost for each node that has more than one selected
-            child.
+            child. Default is ``0``.
     """
 
     def __init__(