Typed GenExpr and ExprCons fields

CHANGELOG.md

@@ -15,6 +15,7 @@
 - Replaced `format()` with f-strings in examples
 - Refactor general expression conversion into per-class `to_scip_expr` recursion
 - Made expression fields read-only to prevent accidental runtime modification
+- Expression fields now use concrete Cython types (`double`/`list`), so values are converted on construction
 - Methods taking a list of variables (e.g. `addConsKnapsack()`) no longer convert it to a NumPy array to check its dimension
 - Speed up `PowExpr._evaluate` via the C-level API
 - `PowExpr._evaluate` now raises `ValueError("math domain error")` for a negative base with a non-integer exponent and `OverflowError` when the result overflows.

src/pyscipopt/expr.pxi

@@ -43,7 +43,7 @@
 # gets called (I guess) and so a copy is returned.
 # Modifying the expression directly would be a bug, given that the expression might be re-used by the user. </pre>
 import warnings
-from typing import TYPE_CHECKING, Literal, Union
+from typing import TYPE_CHECKING, Literal, Optional, Union
 
 import numpy as np
 
@@ -466,11 +466,17 @@ cdef class Expr(ExprLike):
 
 cdef class ExprCons:
     '''Constraints with a polynomial expressions and lower/upper bounds.'''
-    cdef public expr
-    cdef public _lhs
-    cdef public _rhs
 
-    def __init__(self, expr, lhs=None, rhs=None):
+    cdef readonly ExprLike expr
+    cdef readonly object _lhs
+    cdef readonly object _rhs
+
+    def __init__(
+        self,
+        ExprLike expr not None,
+        lhs: Optional[float]=None,
+        rhs: Optional[float]=None,
+    ):
         self.expr = expr
         self._lhs = lhs
         self._rhs = rhs
@@ -575,7 +581,7 @@ Operator = Op()
 cdef class GenExpr(ExprLike):
 
     cdef public _op
-    cdef readonly children
+    cdef readonly list children
 
     def __init__(self): # do we need it
         ''' '''
@@ -756,7 +762,7 @@ cdef class GenExpr(ExprLike):
 # Sum Expressions
 cdef class SumExpr(GenExpr):
 
-    cdef readonly constant
+    cdef readonly double constant
 
     def __init__(self):
         self.constant = 0.0
@@ -810,7 +816,7 @@ cdef class SumExpr(GenExpr):
 # Prod Expressions
 cdef class ProdExpr(GenExpr):
 
-    cdef readonly constant
+    cdef readonly double constant
 
     def __init__(self):
         self.constant = 1.0
@@ -887,7 +893,7 @@ cdef class VarExpr(GenExpr):
 # Pow Expressions
 cdef class PowExpr(GenExpr):
 
-    cdef readonly expo
+    cdef readonly double expo
 
     def __init__(self):
         self.expo = 1.0
@@ -906,14 +912,13 @@ cdef class PowExpr(GenExpr):
 
     cpdef double _evaluate(self, Solution sol) except *:
         cdef double base = (<GenExpr>self.children[0])._evaluate(sol)
-        cdef double expo = <double>self.expo
-        if base == 0.0 and expo < 0:
+        if base == 0.0 and self.expo < 0:
             raise ZeroDivisionError("0.0 cannot be raised to a negative power")
-        elif base < 0.0 and expo != c_floor(expo):
+        elif base < 0.0 and self.expo != c_floor(self.expo):
             raise ValueError("math domain error")
 
-        cdef double res = c_pow(base, expo)
-        if c_fabs(res) == INFINITY and c_fabs(base) != INFINITY and c_fabs(expo) != INFINITY:
+        cdef double res = c_pow(base, self.expo)
+        if c_fabs(res) == INFINITY and c_fabs(base) != INFINITY and c_fabs(self.expo) != INFINITY:
             raise OverflowError("math range error")
         return res
 
@@ -1045,7 +1050,7 @@ cdef class CosExpr(UnaryExpr):
 
 cdef class Constant(GenExpr):
 
-    cdef readonly number
+    cdef readonly double number
 
     def __init__(self, number: Union[int, float]):
         self.number = number

src/pyscipopt/scip.pyi

@@ -249,7 +249,7 @@ class Conshdlr:
 @disjoint_base
 class Constant(GenExpr):
     @property
-    def number(self) -> SupportsFloat: ...
+    def number(self) -> float: ...
     def __init__(self, number: SupportsFloat) -> None: ...
     def __neg__(self, /) -> Constant: ...
     def __pow__(  # type: ignore[override]
@@ -428,11 +428,14 @@ class Expr(ExprLike):
 
 @disjoint_base
 class ExprCons:
-    _lhs: float | None
-    _rhs: float | None
-    expr: Expr | GenExpr
+    @property
+    def expr(self) -> ExprLike: ...
+    @property
+    def _lhs(self) -> float | None: ...
+    @property
+    def _rhs(self) -> float | None: ...
     def __init__(
-        self, expr: Expr | GenExpr, lhs: float | None = None, rhs: float | None = None
+        self, expr: ExprLike, lhs: float | None = None, rhs: float | None = None
     ) -> None: ...
     def normalize(self) -> None: ...
     def __bool__(self) -> bool: ...
@@ -2165,7 +2168,7 @@ class PY_SCIP_STATUS:
 @disjoint_base
 class PowExpr(GenExpr):
     @property
-    def expo(self) -> SupportsFloat: ...
+    def expo(self) -> float: ...
     def __init__(self) -> None: ...
     def __neg__(self, /) -> ProdExpr: ...
 
@@ -2197,7 +2200,7 @@ class Pricer:
 @disjoint_base
 class ProdExpr(GenExpr):
     @property
-    def constant(self) -> SupportsFloat: ...
+    def constant(self) -> float: ...
     def __init__(self) -> None: ...
     def __neg__(self, /) -> ProdExpr: ...
 
@@ -2397,7 +2400,7 @@ class Statistics:
 @disjoint_base
 class SumExpr(GenExpr):
     @property
-    def constant(self) -> SupportsFloat: ...
+    def constant(self) -> float: ...
     def __init__(self) -> None: ...
     def __neg__(self, /) -> ProdExpr: ...