DEP: remove coefs from SumExpr

CHANGELOG.md

@@ -19,6 +19,7 @@
 - Speed up `ProdExpr.__neg__` and `Constant.__neg__` via C-level API (#1250)
 - Extended `structured_optimization_trace` recipe to support context-managed JSONL tracing with final `run_end` records, alongside the existing attach-style in-memory tracing.
 ### Removed
+- `SumExpr`.coefs has been removed; its values were always 1.0 (#1258)
 
 ## 6.2.1 - 2026.05.16
 ### Fixed

src/pyscipopt/expr.pxi

@@ -582,24 +582,20 @@ cdef class GenExpr(ExprLike):
 
         # add left term
         if left.getOp() == Operator.add:
-            ans.coefs.extend(left.coefs)
             ans.children.extend(left.children)
             ans.constant += left.constant
         elif left.getOp() == Operator.const:
             ans.constant += left.number
         else:
-            ans.coefs.append(1.0)
             ans.children.append(left)
 
         # add right term
         if right.getOp() == Operator.add:
-            ans.coefs.extend(right.coefs)
             ans.children.extend(right.children)
             ans.constant += right.constant
         elif right.getOp() == Operator.const:
             ans.constant += right.number
         else:
-            ans.coefs.append(1.0)
             ans.children.append(right)
 
         return ans
@@ -615,18 +611,15 @@ cdef class GenExpr(ExprLike):
     #        if self.getOp() == Operator.const:
     #            newsum.constant += self.number
     #        else:
-    #            newsum.coefs.append(1.0)
     #            newsum.children.append(self.copy()) # TODO: what is copy?
     #        self = newsum
     #    # add right term
     #    if right.getOp() == Operator.add:
-    #        self.coefs.extend(right.coefs)
     #        self.children.extend(right.children)
     #        self.constant += right.constant
     #    elif right.getOp() == Operator.const:
     #        self.constant += right.number
     #    else:
-    #        self.coefs.append(1.0)
     #        self.children.append(right)
     #    return self
 
@@ -740,31 +733,28 @@ cdef class GenExpr(ExprLike):
 cdef class SumExpr(GenExpr):
 
     cdef public constant
-    cdef public coefs
 
     def __init__(self):
         self.constant = 0.0
-        self.coefs = []
         self.children = []
         self._op = Operator.add
+
     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
         for i in range(n):
-            res += <double>coefs[i] * (<GenExpr>children[i])._evaluate(sol)
+            res += (<GenExpr>children[i])._evaluate(sol)
         return res
 
     cdef SumExpr copy(self, bint copy=True):
         cdef SumExpr res = SumExpr.__new__(SumExpr)
         res._op = self._op
         res.children = self.children.copy() if copy else self.children
         res.constant = self.constant
-        res.coefs = self.coefs.copy() if copy else self.coefs
         return res
 
 

src/pyscipopt/scip.pyi

@@ -2354,7 +2354,6 @@ class Statistics:
 
 @disjoint_base
 class SumExpr(GenExpr):
-    coefs: Incomplete
     constant: Incomplete
     def __init__(self, *args: Incomplete, **kwargs: Incomplete) -> None: ...
     def __neg__(self, /) -> ProdExpr: ...