diff --git a/src/samplefunctional.hh b/src/samplefunctional.hh
index 5fa5793feb8a64081aff60c208608b2a9c6a7a3d..6f2d2de496efa95f5670cb0b865739e6807061e6 100644
--- a/src/samplefunctional.hh
+++ b/src/samplefunctional.hh
@@ -31,7 +31,7 @@ class SampleFunctional {
 
   SmallVector descentDirection(const SmallVector x) const {
     if (x == SmallVector(0.0)) {
-      SmallVector d = SmoothGrad(x);
+      SmallVector d = smoothGradient(x);
       // Decline of the smooth part in the negative gradient direction
       double smoothDecline = -(d * d);
       double nonlinearDecline =
@@ -41,8 +41,8 @@ class SampleFunctional {
       return (combinedDecline < 0) ? d : SmallVector(0.0);
     }
 
-    SmallVector const pg = PlusGrad(x);
-    SmallVector const mg = MinusGrad(x);
+    SmallVector const pg = upperGradient(x);
+    SmallVector const mg = lowerGradient(x);
     SmallVector ret;
     // TODO: collinearity checks suck
     if (pg * x == pg.two_norm() * x.two_norm() &&
@@ -53,7 +53,7 @@ class SampleFunctional {
     } else if (pg * x <= 0 && mg * x <= 0) {
       ret = mg;
     } else {
-      ret = project(SmoothGrad(x), x);
+      ret = project(smoothGradient(x), x);
     }
     ret *= -1;
     return ret;
@@ -66,21 +66,21 @@ class SampleFunctional {
   Function func_;
 
   // Gradient of the smooth part
-  SmallVector SmoothGrad(const SmallVector x) const {
+  SmallVector smoothGradient(const SmallVector x) const {
     SmallVector y;
     A.mv(x, y); // y = Av
     y -= b;     // y = Av - b
     return y;
   }
 
-  SmallVector PlusGrad(const SmallVector x) const {
-    SmallVector y = SmoothGrad(x);
+  SmallVector upperGradient(const SmallVector x) const {
+    SmallVector y = smoothGradient(x);
     y.axpy(func_.rightDifferential(x.two_norm()) / x.two_norm(), x);
     return y;
   }
 
-  SmallVector MinusGrad(const SmallVector x) const {
-    SmallVector y = SmoothGrad(x);
+  SmallVector lowerGradient(const SmallVector x) const {
+    SmallVector y = smoothGradient(x);
     y.axpy(func_.leftDifferential(x.two_norm()) / x.two_norm(), x);
     return y;
   }