From cd25b538abff7370100ef5613b8138919f89c7b0 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Sat, 8 Dec 2018 00:13:37 +0100
Subject: Fix noise in sparse_basic_3 (numerical cancellation)

---
 test/sparse_basic.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'test/sparse_basic.cpp')

diff --git a/test/sparse_basic.cpp b/test/sparse_basic.cpp
index 30d3f1bba..30bba3f07 100644
--- a/test/sparse_basic.cpp
+++ b/test/sparse_basic.cpp
@@ -658,7 +658,8 @@ void big_sparse_triplet(Index rows, Index cols, double density) {
   {
     Index r = internal::random<Index>(0,rows-1);
     Index c = internal::random<Index>(0,cols-1);
-    Scalar v = internal::random<Scalar>();
+    // use positive values to prevent numerical cancellation errors in sum
+    Scalar v = numext::abs(internal::random<Scalar>());
     triplets.push_back(TripletType(r,c,v));
     sum += v;
   }
-- 
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