Add model_to_solution and model_to_state. (#145)

# 変更点
- 変更前の時点では、`model_to_solution`
関数が`ommx.v1.State`を返している状態だったため、関数名を`model_to_state`に変更しました
- `ommx.v1.Solution`を返す関数`model_to_solution`を新しく実装しました
- この変更に伴い、`solve`関数の内部処理を新規実装した`model_to_solution`に置き換えました

# 注意事項
`model_to_solution`関数の破壊的変更のため、最低でもマイナーバーションを上げる必要があります。

python/ommx-python-mip-adapter/README.md

@@ -17,7 +17,7 @@ sequenceDiagram
     P->>P: Solve with CBC, Gurobi, or other solvers
     P->>U: Optimized model
     U->>A: Optimized model and ommx.v1.Instance
-    A->>U: ommx:SolutionList
+    A->>U: ommx.v1.Solution
 ```
 
 Python-MIP as a user interface to create OMMX instance
@@ -60,9 +60,9 @@ ommx_instance = Instance.from_components(
 model = adapter.instance_to_model(ommx_instance)
 model.optimize()
 # Create `ommx.v1.State` from Optimized `mip.Model`
-ommx_solutions = adapter.model_to_solution(model, ommx_instance)
+ommx_state = adapter.model_to_state(model, ommx_instance)
 
-print(ommx_solutions)
+print(ommx_state)
 ```
 
 You can get `ommx.v1.Instance` from a Python-MIP model as the following:

python/ommx-python-mip-adapter/docs/source/conf.py

@@ -12,7 +12,7 @@
 copyright = "2024, Jij Inc."
 author = "Jij Inc."
 
-version = "1.3.2"
+version = "1.4.0"
 release = version
 
 # -- General configuration ---------------------------------------------------

python/ommx-python-mip-adapter/ommx_python_mip_adapter/__init__.py

@@ -2,12 +2,14 @@
 from .python_mip_to_ommx import (
     OMMXInstanceBuilder,
     model_to_instance,
+    model_to_state,
     model_to_solution,
 )
 
 __all__ = [
     "instance_to_model",
     "model_to_instance",
+    "model_to_state",
     "model_to_solution",
     "PythonMIPBuilder",
     "OMMXInstanceBuilder",

python/ommx-python-mip-adapter/ommx_python_mip_adapter/ommx_to_python_mip.py

@@ -154,8 +154,8 @@ def instance_to_model(
         >>> model.optimize()
         <OptimizationStatus.OPTIMAL: 0>
 
-        >>> ommx_solutions = adapter.model_to_solution(model, ommx_instance)
-        >>> ommx_solutions.entries
+        >>> ommx_state = adapter.model_to_state(model, ommx_instance)
+        >>> ommx_state.entries
         {1: 0.0}
     """
     builder = PythonMIPBuilder(
@@ -303,26 +303,12 @@ def solve(
     ]:
         return Result(error=f"Unknown status: {model.status}")
 
-    state = model_to_solution(model, instance)
-    solution = instance.evaluate(state)
-
-    assert solution.raw.feasible
+    solution = model_to_solution(model, instance)
 
     if model.status == mip.OptimizationStatus.OPTIMAL:
         solution.raw.optimality = Optimality.OPTIMALITY_OPTIMAL
 
     if relax:
         solution.raw.relaxation = Relaxation.RELAXATION_LP_RELAXED
 
-    dual_variables = {}
-    for constraint in model.constrs:
-        pi = constraint.pi
-        if pi is not None:
-            id = int(constraint.name)
-            dual_variables[id] = pi
-    for constraint in solution.raw.evaluated_constraints:
-        id = constraint.id
-        if id in dual_variables:
-            constraint.dual_variable = dual_variables[id]
-
     return Result(solution=solution.raw)

python/ommx-python-mip-adapter/ommx_python_mip_adapter/python_mip_to_ommx.py

@@ -8,7 +8,7 @@
 from ommx.v1.function_pb2 import Function
 from ommx.v1.linear_pb2 import Linear
 from ommx.v1.solution_pb2 import State
-from ommx.v1 import Instance, DecisionVariable
+from ommx.v1 import Instance, DecisionVariable, Solution
 
 from .exception import OMMXPythonMIPAdapterError
 
@@ -152,7 +152,7 @@ def model_to_instance(model: mip.Model) -> Instance:
     return builder.build()
 
 
-def model_to_solution(
+def model_to_state(
     model: mip.Model,
     instance: Instance,
 ) -> State:
@@ -180,8 +180,8 @@ def model_to_solution(
         >>> model.optimize()
         <OptimizationStatus.OPTIMAL: 0>
 
-        >>> ommx_solutions = adapter.model_to_solution(model, ommx_instance)
-        >>> ommx_solutions.entries
+        >>> ommx_state = adapter.model_to_state(model, ommx_instance)
+        >>> ommx_state.entries
         {1: 0.0}
     """
     if not (
@@ -198,3 +198,54 @@ def model_to_solution(
             for var in instance.raw.decision_variables
         }
     )
+
+
+def model_to_solution(
+    model: mip.Model,
+    instance: Instance,
+) -> Solution:
+    """
+    Convert optimized Python-MIP model and ommx.v1.Instance to ommx.v1.Solution.
+
+    Examples
+    =========
+
+    .. doctest::
+
+        >>> from ommx.v1 import Instance, DecisionVariable
+        >>> from ommx_python_mip_adapter import instance_to_model, model_to_solution
+
+        >>> p = [10, 13, 18, 31, 7, 15]
+        >>> w = [11, 15, 20, 35, 10, 33]
+        >>> x = [DecisionVariable.binary(i) for i in range(6)]
+        >>> instance = Instance.from_components(
+        ...     decision_variables=x,
+        ...     objective=sum(p[i] * x[i] for i in range(6)),
+        ...     constraints=[sum(w[i] * x[i] for i in range(6)) <= 47],
+        ...     sense=Instance.MAXIMIZE,
+        ... )
+
+        >>> model = instance_to_model(instance)
+        >>> model.optimize()
+        <OptimizationStatus.OPTIMAL: 0>
+
+        >>> solution = model_to_solution(model, instance)
+        >>> solution.raw.objective
+        41.0
+
+    """
+    state = model_to_state(model, instance)
+    solution = instance.evaluate(state)
+
+    dual_variables = {}
+    for constraint in model.constrs:
+        pi = constraint.pi
+        if pi is not None:
+            id = int(constraint.name)
+            dual_variables[id] = pi
+    for constraint in solution.raw.evaluated_constraints:
+        id = constraint.id
+        if id in dual_variables:
+            constraint.dual_variable = dual_variables[id]
+
+    return solution

python/ommx-python-mip-adapter/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "ommx_python_mip_adapter"
-version = "1.3.2"
+version = "1.4.0"
 
 description = "An adapter for the Python-MIP from/to OMMX."
 authors = [
@@ -23,7 +23,7 @@ classifiers = [
     "License :: OSI Approved :: MIT License",
 ]
 dependencies = [
-    "ommx >= 1.3.2, < 2.0.0",
+    "ommx >= 1.4.0, < 2.0.0",
 
     # FIXME: This project requires latest version of Python-MIP (will be 1.16.0?), which does not release yet.
     #        https://github.com/coin-or/python-mip/issues/384

python/ommx-python-mip-adapter/tests/test_integration.py

@@ -21,13 +21,11 @@ def test_integration_lp(generater):
 
     model = adapter.instance_to_model(ommx_instance_bytes)
     model.optimize()
-    ommx_solution = adapter.model_to_solution(model, ommx_instance_bytes)
+    ommx_state = adapter.model_to_state(model, ommx_instance_bytes)
     expected_solution = generater.get_v1_state()
-    assert ommx_solution.entries.keys() == expected_solution.entries.keys()
-    for key in ommx_solution.entries.keys():
-        assert ommx_solution.entries[key] == pytest.approx(
-            expected_solution.entries[key]
-        )
+    assert ommx_state.entries.keys() == expected_solution.entries.keys()
+    for key in ommx_state.entries.keys():
+        assert ommx_state.entries[key] == pytest.approx(expected_solution.entries[key])
 
 
 def test_integration_milp():
@@ -54,7 +52,7 @@ def test_integration_milp():
 
     model = adapter.instance_to_model(ommx_instance)
     model.optimize()
-    ommx_solution = adapter.model_to_solution(model, ommx_instance)
+    ommx_state = adapter.model_to_state(model, ommx_instance)
 
-    assert ommx_solution.entries[1] == pytest.approx(3)
-    assert ommx_solution.entries[2] == pytest.approx(3)
+    assert ommx_state.entries[1] == pytest.approx(3)
+    assert ommx_state.entries[2] == pytest.approx(3)

python/ommx/docs/source/conf.py

@@ -13,7 +13,7 @@
 copyright = "2024, Jij Inc."
 author = "Jij Inc."
 
-version = "1.3.2"
+version = "1.4.0"
 release = version
 
 # -- General configuration ---------------------------------------------------

python/ommx/pyproject.toml

@@ -5,7 +5,7 @@ build-backend = "maturin"
 [project]
 name = "ommx"
 
-version = "1.3.2"
+version = "1.4.0"
 description = "Open Mathematical prograMming eXchange (OMMX)"
 authors = [{ name="Jij Inc.", email="info@j-ij.com" }]
 readme = "README.md"