From 6cc7e24114362a5b5f139b080a894c549f5f3000 Mon Sep 17 00:00:00 2001
From: skimo <skimo>
Date: Fri, 30 Jul 2004 14:40:36 +0000
Subject: [PATCH] check for empty polytope

---
 barvinok.cc | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/barvinok.cc b/barvinok.cc
index 0a6622d..44b318a 100644
--- a/barvinok.cc
+++ b/barvinok.cc
@@ -1930,6 +1930,15 @@ static evalue* enumerate_or(Polyhedron *pos, Polyhedron *neg,
     return EP;
 }
 
+static evalue* new_zero_ep()
+{
+    evalue *EP;
+    ALLOC(EP);
+    value_init(EP->d);
+    evalue_set_si(EP, 0, 1);
+    return EP;
+}
+
 static evalue* barvinok_enumerate_e_r(Polyhedron *P, 
 			  unsigned exist, unsigned nparam, unsigned MaxRays);
 
@@ -1977,6 +1986,9 @@ static evalue* barvinok_enumerate_e_r(Polyhedron *P,
     int nvar = P->Dimension - exist - nparam;
     int len = P->Dimension + 2;
 
+    if (emptyQ(P))
+	return new_zero_ep();
+
     if (nvar == 0 && nparam == 0) {
 	evalue *EP;
 	ALLOC(EP);
-- 
2.11.4.GIT