From 04fe01c51ec6ed60478ec3d7927c271b0f2651ec Mon Sep 17 00:00:00 2001
From: Oliver Sander <sander@igpm.rwth-aachen.de>
Date: Sun, 7 Mar 2010 09:28:06 +0000
Subject: [PATCH] add method secondDerivativeOfDistanceSquaredWRTSecondArgument
[[Imported from SVN: r5668]]
---
src/realtuple.hh | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/src/realtuple.hh b/src/realtuple.hh
index d0a3b34e..b326cb98 100644
--- a/src/realtuple.hh
+++ b/src/realtuple.hh
@@ -55,6 +55,20 @@ public:
static EmbeddedTangentVector derivativeOfDistanceSquaredWRTSecondArgument(const RealTuple& a, const RealTuple& b) {
return -2*(a.data_ - b.data_);
}
+
+ /** \brief Compute the Hessian of the squared distance function keeping the first argument fixed
+
+ Unlike the distance itself the squared distance is differentiable at zero
+ */
+ static Dune::FieldMatrix<double,N,N> secondDerivativeOfDistanceSquaredWRTSecondArgument(const RealTuple& a, const RealTuple& b) {
+
+ Dune::FieldMatrix<double,N,N> result;
+ for (int i=0; i<N; i++)
+ for (int j=0; j<N; j++)
+ result[i][j] = (i==j);
+
+ return result;
+ }
/** \brief Write LocalKey object to output stream */
friend std::ostream& operator<< (std::ostream& s, const RealTuple& realTuple)
--
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