priv. ModifiedGradient -> pub. descentDirection

src/bisection-example-new.cc

@@ -29,8 +29,38 @@ class SampleFunctional {
     return y * v + func_(v.two_norm()); // <1/2 Av - b,v> + H(|v|)
   }
 
+  SmallVector descentDirection(const SmallVector x) const {
+    if (x == SmallVector(0.0)) {
+      SmallVector d = SmoothGrad(x);
+      // Decline of the smooth part in the negative gradient direction
+      double smoothDecline = -(d * d);
+      double nonlinearDecline =
+          func_.rightDifferential(0.0) * d.two_norm(); // TODO: is this correct?
+      double combinedDecline = smoothDecline + nonlinearDecline;
+
+      return (combinedDecline < 0) ? d : SmallVector(0.0);
+    }
+
+    SmallVector const pg = PlusGrad(x);
+    SmallVector const mg = MinusGrad(x);
+    SmallVector ret;
+    // TODO: collinearity checks suck
+    if (pg * x == pg.two_norm() * x.two_norm() &&
+        -(mg * x) == mg.two_norm() * x.two_norm()) {
+      return SmallVector(0);
+    } else if (pg * x >= 0 && mg * x >= 0) {
+      ret = pg;
+    } else if (pg * x <= 0 && mg * x <= 0) {
+      ret = mg;
+    } else {
+      ret = project(SmoothGrad(x), x);
+    }
+    ret *= -1;
+    return ret;
+  }
+
   SmallVector minimise(const SmallVector x) const {
-    SmallVector descDir = ModifiedGradient(x);
+    SmallVector descDir = descentDirection(x);
 
     if (descDir == SmallVector(0.0))
       return SmallVector(0.0);
@@ -95,36 +125,6 @@ class SampleFunctional {
     return y;
   }
 
-  SmallVector ModifiedGradient(const SmallVector x) const {
-    if (x == SmallVector(0.0)) {
-      SmallVector d = SmoothGrad(x);
-      // Decline of the smooth part in the negative gradient direction
-      double smoothDecline = -(d * d);
-      double nonlinearDecline =
-          func_.rightDifferential(0.0) * d.two_norm(); // TODO: is this correct?
-      double combinedDecline = smoothDecline + nonlinearDecline;
-
-      return (combinedDecline < 0) ? d : SmallVector(0.0);
-    }
-
-    SmallVector const pg = PlusGrad(x);
-    SmallVector const mg = MinusGrad(x);
-    SmallVector ret;
-    // TODO: collinearity checks suck
-    if (pg * x == pg.two_norm() * x.two_norm() &&
-        -(mg * x) == mg.two_norm() * x.two_norm()) {
-      return SmallVector(0);
-    } else if (pg * x >= 0 && mg * x >= 0) {
-      ret = pg;
-    } else if (pg * x <= 0 && mg * x <= 0) {
-      ret = mg;
-    } else {
-      ret = project(SmoothGrad(x), x);
-    }
-    ret *= -1;
-    return ret;
-  }
-
   // No normalising is done!
   SmallVector project(const SmallVector z, const SmallVector x) const {
     SmallVector y = z;