Recipe for getting local constraints

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 ### Added
+- Added recipe for getting local constraints
 - More support for AND-Constraints
 - Added support for knapsack constraints
 - Added isPositive(), isNegative(), isFeasLE(), isFeasLT(), isFeasGE(), isFeasGT(), isHugeValue(), and tests

src/pyscipopt/recipes/getLocalConss.py

@@ -0,0 +1,24 @@
+from pyscipopt import Model, Constraint
+
+def getLocalConss(model: Model, node = None) -> list[Constraint]:
+    """
+    Returns the local constraints of a node.
+    """
+
+    if not node:
+        assert model.getStageName() in ["INITPRESOLVE", "PRESOLVING", "EXITPRESOLVE", "SOLVING"], "Model cannot be called in stage %s." % model.getStageName()
+        cur_node = model.getCurrentNode()
+    else:
+        cur_node = node
+
+    local_conss = []
+    while cur_node is not None:
+        local_conss = cur_node.getAddedConss() + local_conss
+        cur_node = cur_node.getParent()
+    return local_conss
+
+def getNLocalConss(model: Model) -> int:
+    """
+    Returns the number of local constraints of a node.
+    """
+    return len(getLocalConss(model))

src/pyscipopt/recipes/nonlinear.py

@@ -1,6 +1,5 @@
 from pyscipopt import Model
 
-
 def set_nonlinear_objective(model: Model, expr, sense="minimize"):
     """
     Takes a nonlinear expression and performs an epigraph reformulation.

tests/test_recipe_getLocalConss.py

@@ -0,0 +1,31 @@
+from pyscipopt import Model, SCIP_EVENTTYPE
+from pyscipopt.recipes.getLocalConss import *
+from helpers.utils import random_mip_1
+
+def localconss(model, event):
+    local_conss = getLocalConss(model)
+    assert len(local_conss) == getNLocalConss(model)
+
+    vars = model.getVars()
+    if model.getCurrentNode().getNumber() == 1:
+        pass
+    elif model.getCurrentNode().getNumber() == 2:
+        model.data["local_cons1"] = model.addCons(vars[0] + vars[1] <= 1, name="c1", local=True)
+        assert getNLocalConss(model) == 1
+        assert getLocalConss(model)[0] == model.data["local_cons1"]
+    elif model.getCurrentNode().getParent().getNumber() == 2:
+        local_conss = getLocalConss(model)
+        model.data["local_cons2"] = model.addCons(vars[1] + vars[2] <= 1, name="c2", local=True)
+        model.data["local_cons3"] = model.addCons(vars[2] + vars[3] <= 1, name="c3", local=True)
+        assert getNLocalConss(model) == 3
+        assert getLocalConss(model)[0] == model.data["local_cons1"]
+        assert getLocalConss(model)[1] == model.data["local_cons2"]
+        assert getLocalConss(model)[2] == model.data["local_cons3"]
+
+def test_getLocalConss():
+    model = random_mip_1(node_lim=4)
+    model.data = {}
+
+    model.attachEventHandlerCallback(localconss, [SCIP_EVENTTYPE.NODEFOCUSED])
+    model.optimize()
+    assert len(model.data) == 3