From ce0105f84ef3c8864b435930e6cf2253f9d83516 Mon Sep 17 00:00:00 2001
From: Daniel Arndt <daniel.arndt@iwr.uni-heidelberg.de>
Date: Fri, 17 Aug 2018 15:11:31 +0200
Subject: [PATCH] Implement CUDAWrappers::Vector::norm_sqr

---
 include/deal.II/lac/cuda_vector.h | 11 +++++++++--
 source/lac/cuda_vector.cu         | 11 ++++++++++-
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/include/deal.II/lac/cuda_vector.h b/include/deal.II/lac/cuda_vector.h
index 9c73d8d45d..b6dfb083f0 100644
--- a/include/deal.II/lac/cuda_vector.h
+++ b/include/deal.II/lac/cuda_vector.h
@@ -45,8 +45,9 @@ namespace LinearAlgebra
      *
      * @note Only float and double are supported.
      *
-     * @ingroup CUDAWrappers Vectors
-     * @author Karl Ljungkvist, Bruno Turcksin, 2016
+     * @see CUDAWrappers
+     * @ingroup Vectors
+     * @author Karl Ljungkvist, Bruno Turcksin, Daniel Arndt, 2016, 2018
      */
     template <typename Number>
     class Vector : public VectorSpaceVector<Number>
@@ -233,6 +234,12 @@ namespace LinearAlgebra
       virtual real_type
       l2_norm() const override;
 
+      /**
+       * Return the square of the $l_2$-norm.
+       */
+      real_type
+      norm_sqr() const;
+
       /**
        * Return the maximum norm of the vector (i.e., the maximum absolute
        * value among all entries and among all processors).
diff --git a/source/lac/cuda_vector.cu b/source/lac/cuda_vector.cu
index 9ced53b14e..0cb54b675b 100644
--- a/source/lac/cuda_vector.cu
+++ b/source/lac/cuda_vector.cu
@@ -597,7 +597,16 @@ namespace LinearAlgebra
     typename Vector<Number>::real_type
     Vector<Number>::l2_norm() const
     {
-      return std::sqrt((*this) * (*this));
+      return std::sqrt(norm_sqr());
+    }
+
+
+
+    template <typename Number>
+    typename Vector<Number>::real_type
+    Vector<Number>::norm_sqr() const
+    {
+      return (*this) * (*this);
     }
 
 
-- 
2.39.5