From d06a48959abac6369336d3873d46aee78f8fbec2 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Wed, 25 Jan 2017 15:27:13 +0100
Subject: bug #1383: Fix regression from 3.2 with LinSpaced(n,0,n-1) with n==0.

---
 test/nullary.cpp | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'test/nullary.cpp')

diff --git a/test/nullary.cpp b/test/nullary.cpp
index 351d26e74..bb0cea937 100644
--- a/test/nullary.cpp
+++ b/test/nullary.cpp
@@ -152,6 +152,30 @@ void testVectorType(const VectorType& base)
     m.tail(size-1).setLinSpaced(low, high);
     VERIFY_IS_APPROX(m(size-1), high);
   }
+
+  // regression test for bug 1383 (LinSpaced with empty size/range)
+  {
+    Index n0 = VectorType::SizeAtCompileTime==Dynamic ? 0 : VectorType::SizeAtCompileTime;
+    low = internal::random<Scalar>();
+    m = VectorType::LinSpaced(n0,low,low-1);
+    VERIFY(m.size()==n0);
+
+    if(VectorType::SizeAtCompileTime==Dynamic)
+    {
+      VERIFY_IS_EQUAL(VectorType::LinSpaced(n0,0,Scalar(n0-1)).sum(),Scalar(0));
+      VERIFY_IS_EQUAL(VectorType::LinSpaced(n0,low,low-1).sum(),Scalar(0));
+    }
+
+    m.setLinSpaced(n0,0,Scalar(n0-1));
+    VERIFY(m.size()==n0);
+    m.setLinSpaced(n0,low,low-1);
+    VERIFY(m.size()==n0);
+
+    // empty range only:
+    VERIFY_IS_APPROX(VectorType::LinSpaced(size,low,low),VectorType::Constant(size,low));
+    m.setLinSpaced(size,low,low);
+    VERIFY_IS_APPROX(m,VectorType::Constant(size,low));
+  }
 }
 
 template<typename MatrixType>
-- 
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