From 6c5b7f58f154c2ef19747e6eb22b82e661c96604 Mon Sep 17 00:00:00 2001
From: Elias Pipping <elias.pipping@fu-berlin.de>
Date: Sat, 10 Sep 2011 22:17:10 +0200
Subject: [PATCH] priv. ModifiedGradient -> pub. descentDirection
---
src/bisection-example-new.cc | 62 ++++++++++++++++++------------------
1 file changed, 31 insertions(+), 31 deletions(-)
diff --git a/src/bisection-example-new.cc b/src/bisection-example-new.cc
index 8269baf7..30366162 100644
--- a/src/bisection-example-new.cc
+++ b/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;
--
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