diff --git a/test/rotationtest.cc b/test/rotationtest.cc
index 2970fbaa4cfd7b63694c9531b5cb9426edaa3c02..0e61129a316ad9ac7a2198cb21679de1a0e83537 100644
--- a/test/rotationtest.cc
+++ b/test/rotationtest.cc
@@ -161,47 +161,26 @@ void testDerivativeOfInterpolatedPosition()
double intervalLength = l/(double(3));
Dune::FieldVector<double,3> variation;
- variation = 0; variation[0] = eps;
- fdGrad[0] = Rotation<double,3>::interpolateDerivative(q[i].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))),
- q[j], s);
- variation = 0; variation[0] = -eps;
- fdGrad[0] -= Rotation<double,3>::interpolateDerivative(q[i].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))),
- q[j], s);
- fdGrad[0] /= 2*eps;
-
- variation = 0; variation[1] = eps;
- fdGrad[1] = Rotation<double,3>::interpolateDerivative(q[i].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))),
- q[j], s);
- variation = 0; variation[1] = -eps;
- fdGrad[1] -= Rotation<double,3>::interpolateDerivative(q[i].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))),
- q[j], s);
- fdGrad[1] /= 2*eps;
-
- variation = 0; variation[2] = eps;
- fdGrad[2] = Rotation<double,3>::interpolateDerivative(q[i].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))),
- q[j], s);
- variation = 0; variation[2] = -eps;
- fdGrad[2] -= Rotation<double,3>::interpolateDerivative(q[i].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))),
- q[j], s);
- fdGrad[2] /= 2*eps;
-
- variation = 0; variation[0] = eps;
- fdGrad[3] = Rotation<double,3>::interpolateDerivative(q[i], q[j].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))), s);
- variation = 0; variation[0] = -eps;
- fdGrad[3] -= Rotation<double,3>::interpolateDerivative(q[i], q[j].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))), s);
- fdGrad[3] /= 2*eps;
-
- variation = 0; variation[1] = eps;
- fdGrad[4] = Rotation<double,3>::interpolateDerivative(q[i], q[j].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))), s);
- variation = 0; variation[1] = -eps;
- fdGrad[4] -= Rotation<double,3>::interpolateDerivative(q[i], q[j].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))), s);
- fdGrad[4] /= 2*eps;
-
- variation = 0; variation[2] = -eps;
- fdGrad[5] = Rotation<double,3>::interpolateDerivative(q[i], q[j].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))), s);
- variation = 0; variation[2] = -eps;
- fdGrad[5] -= Rotation<double,3>::interpolateDerivative(q[i], q[j].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))), s);
- fdGrad[5] /= 2*eps;
+ for (int m=0; m<3; m++) {
+ variation = 0;
+ variation[m] = eps;
+ fdGrad[m] = Rotation<double,3>::interpolateDerivative(q[i].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))),
+ q[j], s);
+ variation = 0;
+ variation[m] = -eps;
+ fdGrad[m] -= Rotation<double,3>::interpolateDerivative(q[i].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))),
+ q[j], s);
+ fdGrad[m] /= 2*eps;
+
+ variation = 0;
+ variation[m] = eps;
+ fdGrad[3+m] = Rotation<double,3>::interpolateDerivative(q[i], q[j].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))), s);
+ variation = 0;
+ variation[m] = -eps;
+ fdGrad[3+m] -= Rotation<double,3>::interpolateDerivative(q[i], q[j].mult(Rotation<double,3>::exp(SkewMatrix<double,3>(variation))), s);
+ fdGrad[3+m] /= 2*eps;
+
+ }
// Compute analytical velocity vector gradient
RodLocalStiffness<OneDGrid,double>::interpolationVelocityDerivative(q[i], q[j], s, intervalLength, grad);