type sparse.py, enable mypy in CI

.github/workflows/pythonpackage.yml

@@ -20,13 +20,17 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
-      - name: Update pip
+      - name: Update pip, install dev deps
         run: |
           python -m pip install --upgrade pip
+          pip install -r requirements-dev.txt
       - name: Code Quality
         run: |
           python -m pip install black
           black pulp/ --check
+      - name: Type Check
+        run: |
+          mypy ./
       - name: Install dependencies
         run: |
           python -m pip install .

pulp/sparse.py

@@ -1,3 +1,5 @@
+from typing import Dict, Generic, List, Tuple, TypeVar, cast
+
 # Sparse : Python basic dictionary sparse matrix
 
 # Copyright (c) 2007, Stuart Mitchell (s.mitchell@auckland.ac.nz)
@@ -27,22 +29,31 @@
 notably this allows the sparse matrix to be output in various formats
 """
 
+T = TypeVar("T")
+
 
-class Matrix(dict):
+class Matrix(Generic[T], Dict[Tuple[int, int], T]):
     """This is a dictionary based sparse matrix class"""
 
-    def __init__(self, rows, cols):
+    def __init__(self, rows: List[int], cols: List[int]):
         """initialises the class by creating a matrix that will have the given
         rows and columns
         """
-        self.rows = rows
-        self.cols = cols
-        self.rowdict = {row: {} for row in rows}
-        self.coldict = {col: {} for col in cols}
+        self.rows: List[int] = rows
+        self.cols: List[int] = cols
+        self.rowdict: Dict[int, Dict[int, T]] = {row: {} for row in rows}
+        self.coldict: Dict[int, Dict[int, T]] = {col: {} for col in cols}
 
-    def add(self, row, col, item, colcheck=False, rowcheck=False):
-        if not (rowcheck and row not in self.rows):
-            if not (colcheck and col not in self.cols):
+    def add(
+        self,
+        row: int,
+        col: int,
+        item: T,
+        colcheck: bool = False,
+        rowcheck: bool = False,
+    ) -> None:
+        if not rowcheck or row in self.rows:
+            if not colcheck or col in self.cols:
                 dict.__setitem__(self, (row, col), item)
                 self.rowdict[row][col] = item
                 self.coldict[col][row] = item
@@ -52,20 +63,26 @@ def add(self, row, col, item, colcheck=False, rowcheck=False):
         else:
             raise RuntimeError(f"row {row} is not in the matrix rows")
 
-    def addcol(self, col, rowitems):
+    def addcol(self, col: int, rowitems: Dict[int, T]) -> None:
         """adds a column"""
         if col in self.cols:
             for row, item in rowitems.items():
                 self.add(row, col, item, colcheck=False)
         else:
             raise RuntimeError("col is not in the matrix columns")
 
-    def get(self, k, d=0):
-        return dict.get(self, k, d)
+    def get(  # type: ignore[override]
+        self,
+        coords: Tuple[int, int],
+        default: T = 0,  # type: ignore[assignment]
+    ) -> T:
+        return dict.get(self, coords, default)
 
-    def col_based_arrays(self):
+    def col_based_arrays(
+        self,
+    ) -> Tuple[int, List[int], List[int], List[int], List[T]]:
         numEls = len(self)
-        elemBase = []
+        elemBase: List[T] = []
         startsBase = []
         indBase = []
         lenBase = []
@@ -74,5 +91,6 @@ def col_based_arrays(self):
             elemBase.extend(list(self.coldict[col].values()))
             indBase.extend(list(self.coldict[col].keys()))
             lenBase.append(len(elemBase) - startsBase[-1])
+
         startsBase.append(len(elemBase))
         return numEls, startsBase, lenBase, indBase, elemBase

pulp/tests/test_pulp.py

@@ -1218,7 +1218,6 @@ def add_const(prob):
 
         @gurobi_test
         def test_measuring_solving_time(self):
-
             time_limit = 10
             solver_settings = dict(
                 PULP_CBC_CMD=30,
@@ -1256,7 +1255,6 @@ def test_measuring_solving_time(self):
 
         @gurobi_test
         def test_time_limit_no_solution(self):
-
             time_limit = 1
             solver_settings = dict(HiGHS_CMD=60, HiGHS=60, PULP_CBC_CMD=60, COIN_CMD=60)
             bins = solver_settings.get(self.solver.name)

pulp/tests/test_sparse.py

@@ -4,10 +4,10 @@
 
 
 class SparseTest(unittest.TestCase):
-    def test_sparse(self):
+    def test_sparse(self) -> None:
         rows = list(range(10))
         cols = list(range(50, 60))
-        mat = Matrix(rows, cols)
+        mat = Matrix[str](rows, cols)
         mat.add(1, 52, "item")
         mat.add(2, 54, "stuff")
         assert mat.col_based_arrays() == (
@@ -17,3 +17,39 @@ def test_sparse(self):
             [1, 2],
             ["item", "stuff"],
         )
+
+        assert mat.get((1, 52)) == "item"
+
+        mat.addcol(51, {2: "hello"})
+        assert mat.col_based_arrays() == (
+            3,
+            [0, 0, 1, 2, 2, 3, 3, 3, 3, 3, 3],
+            [0, 1, 1, 0, 1, 0, 0, 0, 0, 0],
+            [2, 1, 2],
+            ["hello", "item", "stuff"],
+        )
+
+    def test_sparse_floats(self) -> None:
+        rows = list(range(10))
+        cols = list(range(50, 60))
+        mat = Matrix[float](rows, cols)
+        mat.add(1, 52, 1.234)
+        mat.add(2, 54, 5.678)
+        assert mat.col_based_arrays() == (
+            2,
+            [0, 0, 0, 1, 1, 2, 2, 2, 2, 2, 2],
+            [0, 0, 1, 0, 1, 0, 0, 0, 0, 0],
+            [1, 2],
+            [1.234, 5.678],
+        )
+
+        assert mat.get((1, 52)) == 1.234
+
+        mat.addcol(51, {2: 9.876})
+        assert mat.col_based_arrays() == (
+            3,
+            [0, 0, 1, 2, 2, 3, 3, 3, 3, 3, 3],
+            [0, 1, 1, 0, 1, 0, 0, 0, 0, 0],
+            [2, 1, 2],
+            [9.876, 1.234, 5.678],
+        )

pyproject.toml

@@ -0,0 +1,17 @@
+[tool.mypy]
+exclude = [
+  "doc/",
+  "examples/",
+  "pulp/__init__.py",
+  "pulp/apis/",
+  "pulp/mps_lp.py",
+  "pulp/pulp.py",
+  "pulp/solverdir/",
+  "pulp/tests/",
+  "pulp/utilities.py",
+  "setup.py",
+  "venv/.*"
+]
+follow_imports = "silent"
+strict = true
+check_untyped_defs = true

requirements-dev.txt

@@ -1,4 +1,5 @@
+black
+mypy
 pre-commit==2.12.0
 sphinx
 sphinx_rtd_theme
-black