multiscale · maarten-ic · Feb 27, 2026 · Feb 27, 2026 · Feb 27, 2026 · Feb 27, 2026
diff --git a/ymmsl/v0_2/__init__.py b/ymmsl/v0_2/__init__.py
@@ -16,6 +16,7 @@
 from ymmsl.v0_2.settings import Settings, SettingValue
 from ymmsl.v0_2.supported_settings import (
         SettingType, SupportedSetting, SupportedSettings)
+from ymmsl.v0_2.timelines import TimelineNode, TimelineTree
 
 
 __all__ = [
@@ -26,4 +27,4 @@
         'MPICoresResReq', 'MPINodesResReq', 'Operator', 'Port', 'Ports', 'Program',
         'Reference', 'ReferencePart', 'resolve', 'ResourceRequirements', 'Settings',
         'SettingType', 'SettingValue', 'SupportedSetting', 'SupportedSettings',
-        'ThreadedResReq', 'Timeline']
+        'ThreadedResReq', 'Timeline', "TimelineNode", "TimelineTree"]
diff --git a/ymmsl/v0_2/model.py b/ymmsl/v0_2/model.py
@@ -117,6 +117,15 @@ def __init__(
                     except ValueError:
                         raise RuntimeError(f'Invalid conduit filter "{f}"')
 
+        # Repeaters must come after reducers
+        is_repeating = False
+        for filter in self.filters:
+            if filter.is_reducer() and is_repeating:
+                raise ValueError(
+                        f"Invalid conduit filters {self.filters}: reducer filters "
+                        "must come before repeater filters.")
+            is_repeating = filter.is_repeater()
+
         self.__check_reference(self.sender)
         self.__check_reference(self.receiver)
 

diff --git a/ymmsl/v0_2/ports.py b/ymmsl/v0_2/ports.py
@@ -1,4 +1,5 @@
 from collections import OrderedDict
+from collections.abc import ItemsView, KeysView, ValuesView
 from typing import Any, cast, Iterator, List, Optional, overload, Sequence, Union
 
 from ymmsl.v0_1.component import Operator   # also the v0.2 version, import from here
@@ -273,6 +274,15 @@ def __iter__(self) -> Iterator[Identifier]:
         for port_name in self._ports:
             yield port_name
 
+    def items(self) -> ItemsView[Identifier, Port]:
+        return self._ports.items()
+
+    def keys(self) -> KeysView[Identifier]:
+        return self._ports.keys()
+
+    def values(self) -> ValuesView[Port]:
+        return self._ports.values()
+
     def sending_port_names(self) -> List[Identifier]:
         """Return the names of all the sending ports.
 

diff --git a/ymmsl/v0_2/tests/test_timelines.py b/ymmsl/v0_2/tests/test_timelines.py
@@ -0,0 +1,107 @@
+from ymmsl.v0_2.timelines import TimelineTree
+from pathlib import Path
+import ymmsl
+from ymmsl.v0_2 import Configuration, Reference as Ref, Timeline, ConduitFilter
+
+import pytest
+
+ROOT_TIMELINE = Timeline(":")
+
+
+@pytest.fixture()
+def timelines_configuration() -> Configuration:
+    return ymmsl.load_as(
+        Configuration, Path(__file__).parent / "ymmsl1/timelines.ymmsl"
+    )
+
+
+def test_consistent_configuration(timelines_configuration: Configuration) -> None:
+    timelines_configuration.check_consistent()
+
+
+def test_dispatch(timelines_configuration: Configuration) -> None:
+    tltree = TimelineTree(timelines_configuration.models[Ref("dispatch")])
+    assert tltree.component_timeline(Ref("first")) == ROOT_TIMELINE
+    assert tltree.component_timeline(Ref("second")) == ROOT_TIMELINE
+
+
+def test_macromicro(timelines_configuration: Configuration) -> None:
+    tltree = TimelineTree(timelines_configuration.models[Ref("macromicro")])
+    assert tltree.component_timeline(Ref("macro")) == ROOT_TIMELINE
+    assert tltree.component_timeline(Ref("micro")) == Timeline(":macro")
+
+
+def test_cycle(timelines_configuration: Configuration) -> None:
+    with pytest.raises(RuntimeError, match="Cycle detected"):
+        TimelineTree(timelines_configuration.models[Ref("cycle")])
+
+
+def test_reducer(timelines_configuration: Configuration) -> None:
+    tltree = TimelineTree(timelines_configuration.models[Ref("reducer")])
+    assert tltree.component_timeline(Ref("first")) == ROOT_TIMELINE
+    assert tltree.component_timeline(Ref("second")) == ROOT_TIMELINE
+
+
+def test_too_many_reducers(timelines_configuration: Configuration) -> None:
+    model = timelines_configuration.models[Ref("reducer")]
+    model.conduits[-1].filters.append(model.conduits[-1].filters[0])
+    with pytest.raises(ValueError, match="Too many reducer filters"):
+        TimelineTree(model)
+
+
+def test_inconsistent_timelines(timelines_configuration: Configuration) -> None:
+    with pytest.raises(ValueError, match="Inconsistent timelines"):
+        TimelineTree(timelines_configuration.models[Ref("inconsistent")])
+
+
+def test_repeaters(timelines_configuration: Configuration) -> None:
+    tltree = TimelineTree(timelines_configuration.models[Ref("repeaters")])
+    assert tltree.component_timeline(Ref("macro")) == ROOT_TIMELINE
+    assert tltree.component_timeline(Ref("meso")) == Timeline(":macro")
+    assert tltree.component_timeline(Ref("micro")) == Timeline(":macro:meso")
+
+
+def test_too_many_repeaters(timelines_configuration: Configuration) -> None:
+    model = timelines_configuration.models[Ref("repeaters")]
+    model.conduits[-2].filters.append(ConduitFilter.REPEAT)
+    with pytest.raises(ValueError, match="Too many repeater filters"):
+        TimelineTree(model)
+
+
+def test_too_few_repeaters(timelines_configuration: Configuration) -> None:
+    model = timelines_configuration.models[Ref("repeaters")]
+    model.conduits[-1].filters.pop()
+    with pytest.raises(ValueError, match="Inconsistent timelines"):
+        TimelineTree(model)
+
+
+def test_repeater_and_too_many_reducers(timelines_configuration: Configuration) -> None:
+    model = timelines_configuration.models[Ref("repeaters")]
+    model.conduits[-1].filters.insert(0, ConduitFilter.LAST)
+    with pytest.raises(ValueError, match="Too many reducer filters"):
+        TimelineTree(model)
+
+
+def test_repeater_after_reducer(timelines_configuration: Configuration) -> None:
+    model = timelines_configuration.models[Ref("repeater_reducer")]
+    tltree = TimelineTree(model)
+    assert tltree.component_timeline(Ref("macro1")) == ROOT_TIMELINE
+    assert tltree.component_timeline(Ref("macro2")) == ROOT_TIMELINE
+    assert tltree.component_timeline(Ref("micro1")) == Timeline(":macro1")
+    assert tltree.component_timeline(Ref("micro2")) == Timeline(":macro2")
+
+    # Removing the filters on the last conduit is a problem
+    model.conduits[-1].filters = []
+    with pytest.raises(ValueError, match="Inconsistent timelines"):
+        TimelineTree(model)
+
+
+def test_repeater_after_reducer_error(timelines_configuration: Configuration) -> None:
+    model = timelines_configuration.models[Ref("repeater_reducer_error")]
+    with pytest.raises(ValueError, match="repeater after reducer"):
+        TimelineTree(model)
+    model.conduits[-1].filters = []
+    tltree = TimelineTree(model)
+    assert tltree.component_timeline(Ref("macro")) == ROOT_TIMELINE
+    assert tltree.component_timeline(Ref("micro1")) == Timeline(":macro")
+    assert tltree.component_timeline(Ref("micro2")) == Timeline(":macro")
diff --git a/ymmsl/v0_2/tests/ymmsl1/timelines.ymmsl b/ymmsl/v0_2/tests/ymmsl1/timelines.ymmsl
@@ -0,0 +1,173 @@
+ymmsl_version: v0.2
+description: Test models for determining timelines
+models:
+  dispatch:
+    ports:
+      f_init: init
+    components:
+      first:
+        description: First component
+        ports:
+          f_init: init
+          o_f: final
+      second:
+        description: Second component
+        ports:
+          f_init: init
+    conduits:
+      init: first.init
+      first.final: second.init
+
+  macromicro:
+    ports:
+      f_init: init
+    components:
+      macro:
+        description: Macro component
+        ports:
+          f_init: init
+          o_i: out
+          s: in
+      micro:
+        description: Micro component
+        ports:
+          f_init: init1 init2
+          o_f: final
+    conduits:
+      init:
+      - macro.init
+      - repeat micro.init1  # Test repeater filter
+      macro.out: micro.init2
+      micro.final: macro.in
+
+  cycle:
+    components:
+      first:
+        description: First component
+        ports:
+          f_init: init
+          o_f: final
+      second:
+        description: Second component
+        ports:
+          f_init: init
+          o_f: final
+    conduits:
+      first.final: second.init
+      second.final: first.init
+
+  reducer:
+    components:
+      first:
+        description: First component
+        ports:
+          o_i: out
+          o_f: final
+      second:
+        description: Second component
+        ports:
+          f_init: init1 init2
+    conduits:
+      first.final: second.init1
+      first.out: last second.init2
+
+  inconsistent:
+    components:
+      macro:
+        description: Macro component
+        ports:
+          o_i: out
+          o_f: final
+      micro:
+        description: Micro component
+        ports:
+          f_init: in
+          o_f: final
+      inconsistent:
+        description: Component with inconsistent timelines
+        ports:
+          f_init: init1 init2
+    conduits:
+      macro.out: micro.in
+      macro.final: inconsistent.init1
+      micro.final: inconsistent.init2
+
+  repeaters:
+    ports:
+      f_init: init
+    components:
+      macro:
+        description: Macro component
+        ports:
+          f_init: init
+          o_i: out
+          s: in
+      meso:
+        description: Meso component
+        ports:
+          f_init: init init2
+          o_i: out
+          s: in
+          o_f: final
+      micro:
+        description: Micro component
+        ports:
+          f_init: init init2
+          o_f: final
+    conduits:
+      macro.out: meso.init
+      meso.final: macro.in
+      meso.out: micro.init
+      micro.final: meso.in
+      init:
+      - macro.init
+      - repeat meso.init2
+      - pad pad micro.init2
+
+  repeater_reducer:
+    components:
+      macro1:
+        description: First macro component
+        ports:
+          o_i: out
+          o_f: final
+      micro1:
+        description: First micro
+        ports:
+          f_init: init
+          o_f: final
+      macro2:
+        description: Second macro component
+        ports:
+          f_init: init
+          o_i: out
+      micro2:
+        description: Second micro
+        ports:
+          f_init: init_micro1 init_macro2
+    conduits:
+      macro1.out: micro1.init
+      macro1.final: macro2.init
+      macro2.out: micro2.init_macro2
+      micro1.final: last repeat micro2.init_micro1
+
+  repeater_reducer_error:
+    components:
+      macro:
+        description: Macro component
+        ports:
+          o_i: out
+      micro1:
+        description: First micro
+        ports:
+          f_init: init
+          o_f: final
+      micro2:
+        description: Second micro
+        ports:
+          f_init: init1 init2
+    conduits:
+      macro.out:
+      - micro1.init
+      - micro2.init1
+      micro1.final: last pad micro2.init2