diff --git a/src/samplefunctional.hh b/src/samplefunctional.hh
index 08790096ff22392de29a604a735b3d5faa1e9e94..acb0e7ea9c8e07b0225112059fd8de7580d041fb 100644
--- a/src/samplefunctional.hh
+++ b/src/samplefunctional.hh
@@ -36,7 +36,7 @@ template <int dim> class SampleFunctional {
 
   void descentDirection(SmallVector const x, SmallVector &ret) const {
     // Check the squared norm rather than each component because
-    // negative_projection() divides by it
+    // complementaryProjection() divides by it
     if (x.two_norm2() == 0.0) {
       // If there is a direction of descent, this is it
       SmallVector d;
@@ -78,7 +78,7 @@ template <int dim> class SampleFunctional {
       // points in direction -x. The projection will then be zero.
       SmallVector d;
       smoothGradient(x, d);
-      negative_projection(d, x, ret);
+      complementaryProjection(d, x, ret);
       dverb << "## Directional derivative (as per scalar product w/ "
                "semigradient): " << -(ret * ret)
             << " (coordinates of the restriction)" << std::endl;
@@ -112,8 +112,8 @@ template <int dim> class SampleFunctional {
   }
 
   // y = (id - P)(d) where P is the projection onto the line t*x
-  void negative_projection(SmallVector const &d, SmallVector const &x,
-                           SmallVector &y) const {
+  void complementaryProjection(SmallVector const &d, SmallVector const &x,
+                               SmallVector &y) const {
     double const dx = d * x;
     double const xx = x.two_norm2();
     y = d;