Speed up -SumExpr, -ProdExpr and -Constant

CHANGELOG.md

@@ -4,7 +4,9 @@
 ### Added
 ### Fixed
 ### Changed
+- Move magic methods (`__radd__`, `__sub__`, `__rsub__`, `__rmul__`, `__richcmp__`, `__neg__`, and `__rtruediv__`) to `ExprLike` base class
 - Speed up `Expr.__add__` and `Expr.__iadd__` via the C-level API
+- Speed up `SumExpr.__neg__`, `ProdExpr.__neg__` and `Constant.__neg__` via C-level API
 ### Removed
 
 ## 6.2.1 - 2026.05.16

src/pyscipopt/expr.pxi

@@ -257,6 +257,27 @@ cdef class ExprLike:
 
         return NotImplemented
 
+    def __radd__(self, other, /):
+        return self + other
+
+    def __sub__(self, other, /):
+        return self + (-other)
+
+    def __rsub__(self, other, /):
+        return (-self) + other
+
+    def __rmul__(self, other, /):
+        return self * other
+
+    def __rtruediv__(self, other, /) -> GenExpr:
+        return buildGenExprObj(other) / self
+
+    def __richcmp__(self, other, int op):
+        return _expr_richcmp(self, other, op)
+
+    def __neg__(self, /) -> Union[Expr, GenExpr]:
+        return self * -1.0
+
     def __abs__(self) -> GenExpr:
         return UnaryExpr(Operator.fabs, buildGenExprObj(self))
 
@@ -358,11 +379,10 @@ cdef class Expr(ExprLike):
             return 1.0 / other * self
         return buildGenExprObj(self) / other
 
-    def __rtruediv__(self, other):
-        ''' other / self '''
+    def __rtruediv__(self, other, /) -> GenExpr:
         if not _is_expr_compatible(other):
             return NotImplemented
-        return buildGenExprObj(other) / self
+        return super().__rtruediv__(other)
 
     def __pow__(self, other, modulo):
         if float(other).is_integer() and other >= 0:
@@ -387,25 +407,6 @@ cdef class Expr(ExprLike):
             raise ValueError("Base of a**x must be positive, as expression is reformulated to scip.exp(x * scip.log(a)); got %g" % base)
         return (self * Constant(base).log()).exp()
 
-    def __neg__(self):
-        return Expr({v:-c for v,c in self.terms.items()})
-
-    def __sub__(self, other):
-        return self + (-other)
-
-    def __radd__(self, other):
-        return self.__add__(other)
-
-    def __rmul__(self, other):
-        return self.__mul__(other)
-
-    def __rsub__(self, other):
-        return -1.0 * self + other
-
-    def __richcmp__(self, other, int op):
-        '''turn it into a constraint'''
-        return _expr_richcmp(self, other, op)
-
     def normalize(self):
         '''remove terms with coefficient of 0'''
         self.terms =  {t:c for (t,c) in self.terms.items() if c != 0.0}
@@ -464,7 +465,6 @@ cdef class ExprCons:
         if not self._rhs is None:
             self._rhs -= c
 
-
     def __richcmp__(self, other, op):
         '''turn it into a constraint'''
         if not _is_number(other):
@@ -690,30 +690,10 @@ cdef class GenExpr(ExprLike):
             raise ZeroDivisionError("cannot divide by 0")
         return self * divisor**(-1)
 
-    def __rtruediv__(self, other):
-        ''' other / self '''
+    def __rtruediv__(self, other, /) -> GenExpr:
         if not _is_genexpr_compatible(other):
             return NotImplemented
-        return buildGenExprObj(other) / self
-
-    def __neg__(self):
-        return -1.0 * self
-
-    def __sub__(self, other):
-        return self + (-other)
-
-    def __radd__(self, other):
-        return self.__add__(other)
-
-    def __rmul__(self, other):
-        return self.__mul__(other)
-
-    def __rsub__(self, other):
-        return -1.0 * self + other
-
-    def __richcmp__(self, other, int op):
-        '''turn it into a constraint'''
-        return _expr_richcmp(self, other, op)
+        return super().__rtruediv__(other)
 
     def degree(self):
         '''Note: none of these expressions should be polynomial'''
@@ -749,14 +729,31 @@ cdef class SumExpr(GenExpr):
         self.coefs = []
         self.children = []
         self._op = Operator.add
+
+    def __neg__(self) -> SumExpr:
+        cdef int i = 0, n = len(self.coefs)
+        cdef list coefs = [0.0] * n
+        cdef double[:] dest_view = coefs
+        cdef double[:] src_view = self.coefs
+
+        for i in range(n):
+            dest_view[i] = -src_view[i]
+
+        cdef SumExpr res = SumExpr.__new__(SumExpr)
+        res.coefs = coefs
+        res.children = self.children.copy()
+        res.constant = -self.constant
+        res._op = Operator.add
+        return res
+
     def __repr__(self):
         return self._op + "(" + str(self.constant) + "," + ",".join(map(lambda child : child.__repr__(), self.children)) + ")"
 
     cpdef double _evaluate(self, Solution sol) except *:
         cdef double res = self.constant
         cdef int i = 0, n = len(self.children)
         cdef list children = self.children
-        cdef list coefs = self.coefs
+        cdef double[:] coefs = self.coefs
         for i in range(n):
             res += <double>coefs[i] * (<GenExpr>children[i])._evaluate(sol)
         return res
@@ -772,6 +769,11 @@ cdef class ProdExpr(GenExpr):
         self.children = []
         self._op = Operator.prod
 
+    def __neg__(self) -> ProdExpr:
+        cdef ProdExpr res = self.copy(copy=True)
+        res.constant = -res.constant
+        return res
+
     def __repr__(self):
         return self._op + "(" + str(self.constant) + "," + ",".join(map(lambda child : child.__repr__(), self.children)) + ")"
 
@@ -841,11 +843,16 @@ cdef class UnaryExpr(GenExpr):
 
 # class for constant expressions
 cdef class Constant(GenExpr):
+
     cdef public number
+
     def __init__(self,number):
         self.number = number
         self._op = Operator.const
 
+    def __neg__(self) -> Constant:
+        return Constant(-self.number)
+
     def __repr__(self):
         return str(self.number)
 

src/pyscipopt/scip.pyi

@@ -331,6 +331,12 @@ class ExprLike:
         *args: Incomplete,
         **kwargs: Incomplete,
     ) -> Incomplete: ...
+    def __radd__(self, other: object, /) -> Incomplete: ...
+    def __sub__(self, other: object, /) -> Incomplete: ...
+    def __rsub__(self, other: object, /) -> Incomplete: ...
+    def __rmul__(self, other: object, /) -> Incomplete: ...
+    def __rtruediv__(self, other: object, /) -> GenExpr: ...
+    def __neg__(self, /) -> Union[Expr, GenExpr]: ...
     def __abs__(self) -> GenExpr: ...
     def exp(self) -> GenExpr: ...
     def log(self) -> GenExpr: ...
@@ -344,7 +350,6 @@ class Expr(ExprLike):
     def __init__(self, terms: Incomplete = ...) -> None: ...
     def degree(self) -> Incomplete: ...
     def normalize(self) -> Incomplete: ...
-    def __abs__(self) -> GenExpr: ...
     def __add__(self, other: Incomplete, /) -> Incomplete: ...
     def __eq__(self, other: object, /) -> bool: ...
     def __ge__(self, other: object, /) -> bool: ...
@@ -356,14 +361,8 @@ class Expr(ExprLike):
     def __lt__(self, other: object, /) -> bool: ...
     def __mul__(self, other: Incomplete, /) -> Incomplete: ...
     def __ne__(self, other: object, /) -> bool: ...
-    def __neg__(self) -> Incomplete: ...
     def __pow__(self, other: Incomplete, modulo: Incomplete = ..., /) -> Incomplete: ...
-    def __radd__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rmul__(self, other: Incomplete, /) -> Incomplete: ...
     def __rpow__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rsub__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rtruediv__(self, other: Incomplete, /) -> Incomplete: ...
-    def __sub__(self, other: Incomplete, /) -> Incomplete: ...
     def __truediv__(self, other: Incomplete, /) -> Incomplete: ...
 
 @disjoint_base
@@ -391,23 +390,23 @@ class GenExpr(ExprLike):
     def degree(self) -> Incomplete: ...
     def getOp(self) -> Incomplete: ...
     def __abs__(self) -> GenExpr: ...
-    def __add__(self, other: Incomplete, /) -> Incomplete: ...
-    def __eq__(self, other: object, /) -> bool: ...
-    def __ge__(self, other: object, /) -> bool: ...
-    def __gt__(self, other: object, /) -> bool: ...
-    def __le__(self, other: object, /) -> bool: ...
-    def __lt__(self, other: object, /) -> bool: ...
-    def __mul__(self, other: Incomplete, /) -> Incomplete: ...
-    def __ne__(self, other: object, /) -> bool: ...
+    def __add__(self, other: Incomplete) -> Incomplete: ...
+    def __eq__(self, other: object) -> bool: ...
+    def __ge__(self, other: object) -> bool: ...
+    def __gt__(self, other: object) -> bool: ...
+    def __le__(self, other: object) -> bool: ...
+    def __lt__(self, other: object) -> bool: ...
+    def __mul__(self, other: Incomplete) -> Incomplete: ...
+    def __ne__(self, other: object) -> bool: ...
     def __neg__(self) -> Incomplete: ...
-    def __pow__(self, other: Incomplete, modulo: Incomplete = ..., /) -> Incomplete: ...
-    def __radd__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rmul__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rpow__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rsub__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rtruediv__(self, other: Incomplete, /) -> Incomplete: ...
-    def __sub__(self, other: Incomplete, /) -> Incomplete: ...
-    def __truediv__(self, other: Incomplete, /) -> Incomplete: ...
+    def __pow__(self, other: Incomplete, modulo: Incomplete = ...) -> Incomplete: ...
+    def __radd__(self, other: Incomplete) -> Incomplete: ...
+    def __rmul__(self, other: Incomplete) -> Incomplete: ...
+    def __rpow__(self, other: Incomplete) -> Incomplete: ...
+    def __rsub__(self, other: Incomplete) -> Incomplete: ...
+    def __rtruediv__(self, other: Incomplete) -> Incomplete: ...
+    def __sub__(self, other: Incomplete) -> Incomplete: ...
+    def __truediv__(self, other: Incomplete) -> Incomplete: ...
 
 @disjoint_base
 class Heur:

tests/test_expr.py

@@ -1,10 +1,17 @@
-import math
-
 import numpy as np
 import pytest
 
 from pyscipopt import Model, cos, exp, log, quickprod, sin, sqrt
-from pyscipopt.scip import CONST, Expr, ExprCons, GenExpr, MatrixGenExpr
+from pyscipopt.scip import (
+    CONST,
+    Constant,
+    Expr,
+    ExprCons,
+    GenExpr,
+    MatrixGenExpr,
+    ProdExpr,
+    SumExpr,
+)
 
 
 @pytest.fixture(scope="module")
@@ -222,6 +229,36 @@ def test_getVal_with_GenExpr():
         m.getVal(1 / z)
 
 
+def test_neg():
+    m = Model()
+    x = m.addVar(name="x")
+
+    expr = (x + 1) ** 3
+    neg_expr = -expr
+    assert isinstance(expr, Expr)
+    assert isinstance(neg_expr, Expr)
+    assert (
+        str(neg_expr)
+        == "Expr({Term(x, x, x): -1.0, Term(x, x): -3.0, Term(x): -3.0, Term(): -1.0})"
+    )
+
+    base = sqrt(x)
+    expr = base * -1
+    neg_expr = -expr
+    assert isinstance(expr, ProdExpr)
+    assert isinstance(neg_expr, ProdExpr)
+    assert str(neg_expr) == "prod(1.0,sqrt(sum(0.0,prod(1.0,x))))"
+
+    expr = base + x - 1
+    neg_expr = -expr
+    assert isinstance(expr, SumExpr)
+    assert isinstance(neg_expr, SumExpr)
+    assert str(neg_expr) == "sum(1.0,sqrt(sum(0.0,prod(1.0,x))),prod(1.0,x))"
+    assert list(neg_expr.coefs) == [-1, -1]
+
+    assert str(-Constant(3.0)) == "-3.0"
+
+
 def test_unary_ufunc(model):
     m, x, y, z = model