Add v2.Problem.get_changes_for_period

Easier access to changes associated with a given period.

Author: dweindl

petab/v2/problem.py

@@ -1126,6 +1126,20 @@ def model_dump(self, **kwargs) -> dict[str, Any]:
             )
         return res
 
+    def get_changes_for_period(
+        self, period: core.ExperimentPeriod
+    ) -> list[core.Change]:
+        """Get the changes for a given experiment period.
+
+        :param period: The experiment period to get the changes for.
+        :return: A list of changes for the given period.
+        """
+        return list(
+            chain.from_iterable(
+                self[condition].changes for condition in period.condition_ids
+            )
+        )
+
 
 class ModelFile(BaseModel):
     """A file in the PEtab problem configuration."""

tests/v2/test_problem.py

@@ -225,3 +225,28 @@ def test_problem_config_paths():
     #  pc.parameter_files[0] = "foo.tsv"
     #  assert isinstance(pc.parameter_files[0], Path)
     # see also https://github.com/pydantic/pydantic/issues/8575
+
+
+def test_get_changes_for_period():
+    """Test getting changes for a specific period."""
+    problem = Problem()
+    ch1 = Change(target_id="target1", target_value=1.0)
+    ch2 = Change(target_id="target2", target_value=2.0)
+    ch3 = Change(target_id="target3", target_value=3.0)
+    cond1 = Condition(id="condition1_1", changes=[ch1])
+    cond2 = Condition(id="condition1_2", changes=[ch2])
+    cond3 = Condition(id="condition2", changes=[ch3])
+    problem += cond1
+    problem += cond2
+    problem += cond3
+
+    p1 = ExperimentPeriod(
+        id="p1", time=0, condition_ids=["condition1_1", "condition1_2"]
+    )
+    p2 = ExperimentPeriod(id="p2", time=1, condition_ids=["condition2"])
+    problem += Experiment(
+        id="exp1",
+        periods=[p1, p2],
+    )
+    assert problem.get_changes_for_period(p1) == [ch1, ch2]
+    assert problem.get_changes_for_period(p2) == [ch3]