Using LU decomposition with complete pivoting for better accuracy.

2 files changed, 4 insertions, 3 deletions

diff --git a/unsupported/Eigen/src/Splines/SplineFitting.h b/unsupported/Eigen/src/Splines/SplineFitting.h
index c30129983..3b8e70a18 100644
--- a/unsupported/Eigen/src/Splines/SplineFitting.h
+++ b/unsupported/Eigen/src/Splines/SplineFitting.h
@@ -17,6 +17,7 @@
 
 #include "SplineFwd.h"
 
+#include <Eigen/LU>
 #include <Eigen/QR>
 
 namespace Eigen
@@ -404,8 +405,8 @@ namespace Eigen
     A(n - 1, n - 1) = 1;
     
     // Solve
-    HouseholderQR<MatrixType> qr(A);
-    ControlPointVectorType controlPoints = qr.solve(MatrixType(b.transpose())).transpose();
+    FullPivLU<MatrixType> lu(A);
+    ControlPointVectorType controlPoints = lu.solve(MatrixType(b.transpose())).transpose();
 
     SplineType spline(knots, controlPoints);
     
diff --git a/unsupported/test/splines.cpp b/unsupported/test/splines.cpp
index 1f3856143..755a21ece 100644
--- a/unsupported/test/splines.cpp
+++ b/unsupported/test/splines.cpp
@@ -261,7 +261,7 @@ void check_global_interpolation_with_derivatives2d()
   {
     PointType point = spline(knots(i));
     PointType referencePoint = points.col(i);
-    VERIFY((point - referencePoint).matrix().norm() < 1e-12);
+    VERIFY((point - referencePoint).matrix().norm() < 1e-10);
     PointType derivative = spline.derivatives(knots(i), 1).col(1);
     PointType referenceDerivative = derivatives.col(i);
     VERIFY((derivative - referenceDerivative).matrix().norm() < 1e-10);