Remove hard numpy dep

Author: mrmundt

pyomo/contrib/solver/solvers/xpress/xpress_base.py

@@ -40,7 +40,7 @@
 from typing import Any, Iterator, Mapping, Optional, Sequence, cast
 
 from pyomo.common.collections import ComponentMap
-from pyomo.common.dependencies import attempt_import, numpy as np
+from pyomo.common.dependencies import attempt_import
 from pyomo.common.errors import InfeasibleConstraintException
 from pyomo.common.tee import capture_output, TeeStream
 from pyomo.common.timing import HierarchicalTimer
@@ -93,7 +93,7 @@
 
 # ---- Pure-Python module-level constants (no xp dependency) ------------------
 
-_BOUND_TYPE_CODES = np.array([76, 85], dtype=np.int8)  # 'L', 'U'
+_BOUND_TYPE_CODES = ['L', 'U']
 
 _VAR_TYPE_CODES: dict[tuple[bool, bool], int] = {
     (True, True): 66,  # 'B' -- binary (implies integer)
@@ -515,7 +515,8 @@ def _set_var_bounds(self, prob, pyo_vars: list[VarData], xp_vars) -> None:
         """Bulk-set variable bounds for pyo_vars, respecting fixed-var pinning."""
         n = len(pyo_vars)
         cbounds = [b for var in pyo_vars for b in self._var_bounds(var)]
-        prob.chgBounds(np.repeat(xp_vars, 2), np.tile(_BOUND_TYPE_CODES, n), cbounds)
+        cols = [v for v in xp_vars for _ in range(2)]
+        prob.chgBounds(cols, _BOUND_TYPE_CODES * n, cbounds)
 
     def _add_vars_impl(self, prob, pyo_vars: list[VarData], symbolic_labels: bool):
         """Add columns, set types and bounds. Returns the xp.var array.
@@ -579,16 +580,15 @@ def _add_sos_impl(
         n = len(pyo_sos)
         if n == 0:
             return []
-        settype = np.empty(n, dtype=np.int8)
-        setstart = np.empty(n + 1, dtype=np.int64)
-        setstart[0] = 0
+        settype: list[int] = []
+        setstart: list[int] = [0]
         setind: list[int] = []
         refval: list[float] = []
-        for i, con in enumerate(pyo_sos):
+        for con in pyo_sos:
             setind.extend(var_map[id(var)].index for var in con.variables)
             refval.extend(float(w) for _, w in con.get_items())
-            settype[i] = ord('1' if con.level == 1 else '2')
-            setstart[i + 1] = len(setind)
+            settype.append(ord('1' if con.level == 1 else '2'))
+            setstart.append(len(setind))
         nsos = prob.attributes.sets
         prob.addSets(settype, setstart, setind, refval)
         if symbolic_labels:
@@ -597,18 +597,15 @@ def _add_sos_impl(
         return prob.getSOS(first=nsos, last=nsos + n - 1)
 
     def _warmstart(self, prob, vars: list[VarData], entind: list[int]) -> None:
-        n = len(entind)
-        ws_vals = np.empty(n, dtype=np.float64)
-        ws_cols = np.empty(n, dtype=np.int32)
-        count = 0
+        ws_vals: list[float] = []
+        ws_cols: list[int] = []
         for j in entind:
             var = vars[j]
             if var.value is not None:
-                ws_vals[count] = var.value
-                ws_cols[count] = j
-                count += 1
-        if count > 0:
-            prob.addMipSol(ws_vals[:count], ws_cols[:count])
+                ws_vals.append(var.value)
+                ws_cols.append(j)
+        if ws_vals:
+            prob.addMipSol(ws_vals, ws_cols)
 
     def _apply_solver_controls(self, prob, config: BranchAndBoundConfig) -> None:
         if config.time_limit is not None: