feat: move set_int_index to solution assignment in model.py

.gitignore

@@ -17,6 +17,14 @@ Highs.log
 paper/
 monkeytype.sqlite3
 
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
 
 benchmark/*.pdf
 benchmark/benchmarks

doc/release_notes.rst

@@ -1,8 +1,10 @@
 Release Notes
 =============
 
-.. Upcoming Version
-.. ----------------
+Upcoming Version
+----------------
+
+* The internal handling of `Solution` objects was improved for more consistency. Solution objects created from solver calls now preserve the exact index names from the input file.
 
 Version 0.4.4
 --------------

linopy/common.py

@@ -38,6 +38,16 @@
     from linopy.variables import Variable
 
 
+def set_int_index(series: pd.Series) -> pd.Series:
+    """
+    Convert string index to int index.
+    """
+    if not series.empty and not series.index.is_integer():
+        cutoff = count_initial_letters(str(series.index[0]))
+        series.index = series.index.str[cutoff:].astype(int)
+    return series
+
+
 def maybe_replace_sign(sign: str) -> str:
     """
     Replace the sign with an alternative sign if available.

linopy/model.py

@@ -30,6 +30,7 @@
     best_int,
     maybe_replace_signs,
     replace_by_map,
+    set_int_index,
     to_path,
 )
 from linopy.constants import (
@@ -1189,6 +1190,7 @@ def solve(
 
         # map solution and dual to original shape which includes missing values
         sol = result.solution.primal.copy()
+        sol = set_int_index(sol)
         sol.loc[-1] = nan
 
         for name, var in self.variables.items():
@@ -1201,6 +1203,7 @@ def solve(
 
         if not result.solution.dual.empty:
             dual = result.solution.dual.copy()
+            dual = set_int_index(dual)
             dual.loc[-1] = nan
 
             for name, con in self.constraints.items():

linopy/solvers.py

@@ -19,9 +19,7 @@
 
 import numpy as np
 import pandas as pd
-from pandas.core.series import Series
 
-from linopy.common import count_initial_letters
 from linopy.constants import (
     Result,
     Solution,
@@ -135,16 +133,6 @@
 )
 
 
-def set_int_index(series: Series) -> Series:
-    """
-    Convert string index to int index.
-    """
-    if not series.empty:
-        cutoff = count_initial_letters(str(series.index[0]))
-        series.index = series.index.str[cutoff:].astype(int)
-    return series
-
-
 # using enum to match solver subclasses with names
 class SolverName(enum.Enum):
     CBC = "cbc"
@@ -466,8 +454,8 @@ def get_solver_solution():
             )
             variables_b = df.index.str[0] == "x"
 
-            sol = df[variables_b][2].pipe(set_int_index)
-            dual = df[~variables_b][3].pipe(set_int_index)
+            sol = df[variables_b][2]
+            dual = df[~variables_b][3]
             return Solution(sol, dual, objective)
 
         solution = self.safe_get_solution(status=status, func=get_solver_solution)
@@ -624,11 +612,7 @@ def get_solver_solution() -> Solution:
             dual_io = io.StringIO("".join(read_until_break(f))[:-2])
             dual_ = pd.read_fwf(dual_io)[1:].set_index("Row name")
             if "Marginal" in dual_:
-                dual = (
-                    pd.to_numeric(dual_["Marginal"], "coerce")
-                    .fillna(0)
-                    .pipe(set_int_index)
-                )
+                dual = pd.to_numeric(dual_["Marginal"], "coerce").fillna(0)
             else:
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -638,7 +622,6 @@ def get_solver_solution() -> Solution:
                 pd.read_fwf(sol_io)[1:]
                 .set_index("Column name")["Activity"]
                 .astype(float)
-                .pipe(set_int_index)
             )
             f.close()
             return Solution(sol, dual, objective)
@@ -860,12 +843,8 @@ def get_solver_solution() -> Solution:
                 sol = pd.Series(solution.col_value, model.matrices.vlabels, dtype=float)
                 dual = pd.Series(solution.row_dual, model.matrices.clabels, dtype=float)
             else:
-                sol = pd.Series(
-                    solution.col_value, h.getLp().col_names_, dtype=float
-                ).pipe(set_int_index)
-                dual = pd.Series(
-                    solution.row_dual, h.getLp().row_names_, dtype=float
-                ).pipe(set_int_index)
+                sol = pd.Series(solution.col_value, h.getLp().col_names_, dtype=float)
+                dual = pd.Series(solution.row_dual, h.getLp().row_names_, dtype=float)
 
             return Solution(sol, dual, objective)
 
@@ -1084,13 +1063,11 @@ def get_solver_solution() -> Solution:
             objective = m.ObjVal
 
             sol = pd.Series({v.VarName: v.x for v in m.getVars()}, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual = pd.Series(
                     {c.ConstrName: c.Pi for c in m.getConstrs()}, dtype=float
                 )
-                dual = set_int_index(dual)
             except AttributeError:
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1229,15 +1206,13 @@ def get_solver_solution() -> Solution:
             solution = pd.Series(
                 m.solution.get_values(), m.variables.get_names(), dtype=float
             )
-            solution = set_int_index(solution)
 
             if is_lp:
                 dual = pd.Series(
                     m.solution.get_dual_values(),
                     m.linear_constraints.get_names(),
                     dtype=float,
                 )
-                dual = set_int_index(dual)
             else:
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1366,15 +1341,13 @@ def get_solver_solution() -> Solution:
             sol.drop(
                 ["quadobjvar", "qmatrixvar"], errors="ignore", inplace=True, axis=0
             )
-            sol = set_int_index(sol)
 
             cons = m.getConss()
             if len(cons) != 0:
                 dual = pd.Series({c.name: m.getDualSolVal(c) for c in cons})
                 dual = dual[
                     dual.index.str.startswith("c") & ~dual.index.str.startswith("cf")
                 ]
-                dual = set_int_index(dual)
             else:
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1504,12 +1477,10 @@ def get_solver_solution() -> Solution:
             var = [str(v) for v in m.getVariable()]
 
             sol = pd.Series(m.getSolution(var), index=var, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual_ = [str(d) for d in m.getConstraint()]
                 dual = pd.Series(m.getDual(dual_), index=dual_, dtype=float)
-                dual = set_int_index(dual)
             except (xpress.SolverError, xpress.ModelError, SystemError):
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1833,13 +1804,11 @@ def get_solver_solution() -> Solution:
             sol = m.getxx(soltype)
             sol = {m.getvarname(i): sol[i] for i in range(m.getnumvar())}
             sol = pd.Series(sol, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual = m.gety(soltype)
                 dual = {m.getconname(i): dual[i] for i in range(m.getnumcon())}
                 dual = pd.Series(dual, dtype=float)
-                dual = set_int_index(dual)
             except (mosek.Error, AttributeError):
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1975,11 +1944,9 @@ def get_solver_solution() -> Solution:
             objective = m.BestObj if m.ismip else m.LpObjVal
 
             sol = pd.Series({v.name: v.x for v in m.getVars()}, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual = pd.Series({v.name: v.pi for v in m.getConstrs()}, dtype=float)
-                dual = set_int_index(dual)
             except (coptpy.CoptError, AttributeError):
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -2119,11 +2086,9 @@ def get_solver_solution() -> Solution:
             objective = m.objval
 
             sol = pd.Series({v.varname: v.X for v in m.getVars()}, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual = pd.Series({c.constrname: c.DualSoln for c in m.getConstrs()})
-                dual = set_int_index(dual)
             except (mindoptpy.MindoptError, AttributeError):
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)

linopy/variables.py

@@ -47,12 +47,12 @@
     print_coord,
     print_single_variable,
     save_join,
+    set_int_index,
     to_dataframe,
     to_polars,
 )
 from linopy.config import options
 from linopy.constants import HELPER_DIMS, TERM_DIM
-from linopy.solvers import set_int_index
 from linopy.types import NotImplementedType
 
 if TYPE_CHECKING:

test/test_solvers.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""
+Created on Tue Jan 28 09:03:35 2025.
+
+@author: sid
+"""
+
+import pytest
+
+from linopy import solvers
+
+free_mps_problem = """NAME          sample_mip
+ROWS
+ N  obj
+ G  c1
+ L  c2
+ E  c3
+COLUMNS
+    col1        obj       5
+    col1        c1        2
+    col1        c2        4
+    col1        c3        1
+    MARK0000  'MARKER'                 'INTORG'
+    colu2        obj       3
+    colu2        c1        3
+    colu2        c2        2
+    colu2        c3        1
+    col3        obj       7
+    col3        c1        4
+    col3        c2        3
+    col3        c3        1
+    MARK0001  'MARKER'                 'INTEND'
+RHS
+    RHS_V     c1        12
+    RHS_V     c2        15
+    RHS_V     c3        6
+BOUNDS
+ UP BOUND     col1        4
+ UI BOUND     colu2        3
+ UI BOUND     col3        5
+ENDATA
+"""
+
+
+@pytest.mark.parametrize("solver", set(solvers.available_solvers))
+def test_free_mps_solution_parsing(solver, tmp_path):
+    try:
+        solver_enum = solvers.SolverName(solver.lower())
+        solver_class = getattr(solvers, solver_enum.name)
+    except ValueError:
+        raise ValueError(f"Solver '{solver}' is not recognized")
+
+    # Write the MPS file to the temporary directory
+    mps_file = tmp_path / "problem.mps"
+    mps_file.write_text(free_mps_problem)
+
+    # Create a solution file path in the temporary directory
+    sol_file = tmp_path / "solution.sol"
+
+    s = solver_class()
+    result = s.solve_problem(problem_fn=mps_file, solution_fn=sol_file)
+
+    assert result.status.is_ok
+    assert result.solution.objective == 30.0