From 6588b185a8b76041afc6c9ce521c53a33b6f5ff1 Mon Sep 17 00:00:00 2001
From: Elias Pipping <elias.pipping@fu-berlin.de>
Date: Fri, 9 Sep 2011 18:19:03 +0200
Subject: [PATCH] Use bisection class from dune-tnnmg
---
src/bisection-example-new.cc | 65 +++++++-----------------------------
1 file changed, 12 insertions(+), 53 deletions(-)
diff --git a/src/bisection-example-new.cc b/src/bisection-example-new.cc
index 6df06d37..c44375fe 100644
--- a/src/bisection-example-new.cc
+++ b/src/bisection-example-new.cc
@@ -49,7 +49,7 @@ class SampleFunctional {
return (x * dir > 0) ? PlusGrad(x) * dir : MinusGrad(x) * dir;
}
- SmallVector minimise(const SmallVector x, unsigned int iterations) const {
+ SmallVector minimise(const SmallVector x) const {
SmallVector descDir = ModifiedGradient(x);
if (descDir == SmallVector(0.0))
@@ -75,57 +75,14 @@ class SampleFunctional {
MyDirectionalConvexFunctionType;
MyDirectionalConvexFunctionType rest(rest_A, rest_b, phi, x, descDir);
- Interval<double> D;
-
- // { Debugging
- Dune::dverb << "Starting at x with J(x) = " << operator()(x) << std::endl;
- SmallVector debug_normalised_dir = descDir;
- debug_normalised_dir /= debug_normalised_dir.two_norm();
- Dune::dverb << "Minimizing in direction w with dJ(x,w) = "
- << directionalDerivative(x, debug_normalised_dir) << std::endl;
- // }
-
- double l = 0;
- double r = 1;
- while (true) {
- rest.subDiff(r, D);
- if (D[1] >= 0)
- break;
-
- l = r;
- r *= 2;
- Dune::dverb << "Widened interval!" << std::endl;
- }
- Dune::dverb << "Interval now [" << l << "," << r << "]" << std::endl;
-
- { // Debugging
- SmallVector tmpl = x;
- tmpl.axpy(l, descDir);
- SmallVector tmpr = x;
- tmpr.axpy(r, descDir);
- assert(directionalDerivative(tmpl, debug_normalised_dir) < 0);
- assert(directionalDerivative(tmpr, debug_normalised_dir) > 0);
- }
+ Bisection bisection; // FIXME: default values
+ int count;
+ // FIXME: does x_old = 1 make any sense?!
+ double const m = bisection.minimize(rest, 0.0, 1.0, count);
+ Dune::dverb << "Number of iterations in the bisection method: " << count
+ << std::endl;
+ ;
- double m = l / 2 + r / 2;
- for (unsigned int count = 0; count < iterations; ++count) {
- { // Debugging
- Dune::dverb << "now at m = " << m << std::endl;
- SmallVector tmp = x;
- tmp.axpy(m, descDir);
- Dune::dverb << "Value of J here: " << operator()(tmp) << std::endl;
- }
-
- rest.subDiff(m, D);
- if (D[1] < 0) {
- l = m;
- m = (m + r) / 2;
- } else if (D[1] > 0) {
- r = m;
- m = (l + m) / 2;
- } else
- break;
- }
SmallVector middle = descDir;
middle *= m;
return middle;
@@ -220,8 +177,9 @@ void testSampleFunction() {
SampleFunctional::SmallVector correction;
for (int i = 1; i <= 6; ++i) {
- correction = J.minimise(start, 20);
+ correction = J.minimise(start);
start += correction;
+ std::cout << "New value: J(...) = " << J(start) << std::endl;
}
std::cout << "Arrived at J(...) = " << J(start) << std::endl;
}
@@ -251,8 +209,9 @@ void testTrivialFunction() {
SampleFunctional::SmallVector correction;
for (int i = 1; i <= 5; ++i) {
- correction = J.minimise(start, 20);
+ correction = J.minimise(start);
start += correction;
+ std::cout << "New value: J(...) = " << J(start) << std::endl;
}
std::cout << "Arrived at J(...) = " << J(start) << std::endl;
}
--
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