From ef022da28e51632458f92baabb539bf13a221694 Mon Sep 17 00:00:00 2001
From: Hauke Heibel <hauke.heibel@gmail.com>
Date: Wed, 7 Mar 2012 15:34:39 +0100
Subject: [PATCH] Fixed setLinSpaced for size==1.

---
 Eigen/src/Core/CwiseNullaryOp.h |  5 +++++
 Eigen/src/Core/Functors.h       |  2 +-
 test/nullary.cpp                | 10 ++++++++--
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/Eigen/src/Core/CwiseNullaryOp.h b/Eigen/src/Core/CwiseNullaryOp.h
index 0fb2c7bc1..05cc2526d 100644
--- a/Eigen/src/Core/CwiseNullaryOp.h
+++ b/Eigen/src/Core/CwiseNullaryOp.h
@@ -241,6 +241,8 @@ DenseBase<Derived>::Constant(const Scalar& value)
   * assumed to be a(0), a(1), ..., a(size). This assumption allows for better vectorization
   * and yields faster code than the random access version.
   *
+  * When size is set to 1, a vector of length 1 containing 'high' is returned.
+  *
   * \only_for_vectors
   *
   * Example: \include DenseBase_LinSpaced_seq.cpp
@@ -273,6 +275,7 @@ DenseBase<Derived>::LinSpaced(Sequential_t, const Scalar& low, const Scalar& hig
   * \brief Sets a linearly space vector.
   *
   * The function generates 'size' equally spaced values in the closed interval [low,high].
+  * When size is set to 1, a vector of length 1 containing 'high' is returned.
   *
   * \only_for_vectors
   *
@@ -384,6 +387,7 @@ PlainObjectBase<Derived>::setConstant(Index rows, Index cols, const Scalar& valu
   * \brief Sets a linearly space vector.
   *
   * The function generates 'size' equally spaced values in the closed interval [low,high].
+  * When size is set to 1, a vector of length 1 containing 'high' is returned.
   *
   * \only_for_vectors
   *
@@ -403,6 +407,7 @@ EIGEN_STRONG_INLINE Derived& DenseBase<Derived>::setLinSpaced(Index size, const
   * \brief Sets a linearly space vector.
   *
   * The function fill *this with equally spaced values in the closed interval [low,high].
+  * When size is set to 1, a vector of length 1 containing 'high' is returned.
   *
   * \only_for_vectors
   *
diff --git a/Eigen/src/Core/Functors.h b/Eigen/src/Core/Functors.h
index cbda77c2d..1d641b19f 100644
--- a/Eigen/src/Core/Functors.h
+++ b/Eigen/src/Core/Functors.h
@@ -628,7 +628,7 @@ template <typename Scalar, bool RandomAccess> struct functor_traits< linspaced_o
 template <typename Scalar, bool RandomAccess> struct linspaced_op
 {
   typedef typename packet_traits<Scalar>::type Packet;
-  linspaced_op(Scalar low, Scalar high, int num_steps) : impl(low, (high-low)/(num_steps-1)) {}
+  linspaced_op(Scalar low, Scalar high, int num_steps) : impl((num_steps==1 ? high : low), (num_steps==1 ? 1 : (high-low)/(num_steps-1))) {}
 
   template<typename Index>
   EIGEN_STRONG_INLINE const Scalar operator() (Index i) const { return impl(i); }
diff --git a/test/nullary.cpp b/test/nullary.cpp
index 0df15c081..501b579b0 100644
--- a/test/nullary.cpp
+++ b/test/nullary.cpp
@@ -76,8 +76,8 @@ void testVectorType(const VectorType& base)
   VERIFY( (MatrixXd(RowVectorXd::LinSpaced(3, 0, 1)) - RowVector3d(0, 0.5, 1)).norm() < std::numeric_limits<Scalar>::epsilon() );
 
   // These guys sometimes fail! This is not good. Any ideas how to fix them!?
-//   VERIFY( m(m.size()-1) == high );
-//   VERIFY( m(0) == low );
+  //VERIFY( m(m.size()-1) == high );
+  //VERIFY( m(0) == low );
 
   // sequential access version
   m = VectorType::LinSpaced(Sequential,size,low,high);
@@ -97,6 +97,12 @@ void testVectorType(const VectorType& base)
   Matrix<Scalar,Dynamic,1> size_changer(size+50);
   size_changer.setLinSpaced(size,low,high);
   VERIFY( size_changer.size() == size );
+
+  typedef Matrix<Scalar,1,1> ScalarMatrix;
+  ScalarMatrix scalar;
+  scalar.setLinSpaced(1,low,high);
+  VERIFY_IS_APPROX( scalar, ScalarMatrix::Constant(high) );
+  VERIFY_IS_APPROX( ScalarMatrix::LinSpaced(1,low,high), ScalarMatrix::Constant(high) );
 }
 
 template<typename MatrixType>