From 9a3bf4ddd414fde8e8e25009e543432b3b1822d4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?AlexanderM=C3=BCller?= <mueller@uni-stuttgart.de>
Date: Thu, 29 Apr 2021 12:44:09 +0200
Subject: [PATCH] added block,blockAt, segment, segmentAt and RandomVector
functionality
---
dune/gfe/linearalgebra.hh | 62 +++++++++++++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)
diff --git a/dune/gfe/linearalgebra.hh b/dune/gfe/linearalgebra.hh
index f23d3ea9..ea2f220d 100644
--- a/dune/gfe/linearalgebra.hh
+++ b/dune/gfe/linearalgebra.hh
@@ -1,6 +1,8 @@
#ifndef DUNE_GFE_LINEARALGEBRA_HH
#define DUNE_GFE_LINEARALGEBRA_HH
+#include <random>
+
#include <dune/common/fmatrix.hh>
#include <dune/common/version.hh>
@@ -119,6 +121,66 @@ namespace Dune {
}
#endif
+ /** \brief Return a segment of a FieldVector from lower up to lower+size-1 */
+ template< int lower, int size,typename field_type,int n>
+ static FieldVector<field_type,size> segment(const FieldVector<field_type,n>& v)
+ {
+ FieldVector<field_type,size> res;
+ std::copy(v.begin()+lower,v.begin()+lower+size,res.begin());
+ return res;
+ }
+
+ /** \brief Return a segment of a FieldVector from lower up to lower+size-1
+ * lower is unkown at compile time*/
+ template< int size,typename field_type,int n>
+ static FieldVector<field_type,size> segmentAt(const FieldVector<field_type,n>& v,const size_t lower)
+ {
+ FieldVector<field_type,size> res;
+ std::copy(v.begin()+lower,v.begin()+lower+size,res.begin());
+ return res;
+ }
+
+ /** \brief Return a block of a FieldMatrix (lower1...lower1+size1-1,lower2...lower2+size2-1 */
+ template< int lower1, int size1, int lower2,int size2,typename field_type,int n,int m>
+ static auto block(const FieldMatrix<field_type,n,m>& v)
+ {
+ static_assert(lower1+size1<=n && lower2+size2<=m, "Size mismatch for Block!");
+ FieldMatrix<field_type,size1,size2> res;
+
+ for(int i=lower1; i<lower1+size1; ++i)
+ for(int j=lower2; j<lower2+size2; ++j)
+ res[i-lower1][j-lower2] = v[i][j];
+ return res;
+ }
+
+ /** \brief Return a block of a FieldMatrix (lower1...lower1+size1-1,lower2...lower2+size2-1
+ * * lower1 and lower2 is unkown at compile time*/
+ template< int size1,int size2,typename field_type,int n,int m>
+ static auto blockAt(const FieldMatrix<field_type,n,m>& v, const size_t& lower1, const size_t& lower2)
+ {
+ assert(lower1+size1<=n && lower2+size2<=m);
+ FieldMatrix<field_type,size1,size2> res;
+
+ for(size_t i=lower1; i<lower1+size1; ++i)
+ for(size_t j=lower2; j<lower2+size2; ++j)
+ res[i-lower1][j-lower2] = v[i][j];
+ return res;
+ }
+
+ /** \brief Generates FieldVector with random entries in the range -1..1 */
+ template<typename field_type,int n>
+ auto randomFieldVector(field_type lower=-1, field_type upper=1)
+ {
+ std::random_device rd;
+ std::mt19937 mt(rd());
+ std::uniform_real_distribution<field_type> dist(lower, upper);
+ auto rand = [&dist,&mt](){
+ return dist(mt);
+ };
+ FieldVector<field_type,n> vec;
+ std::generate(vec.begin(), vec.end(), rand);
+ return vec;
+ }
}
}
--
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