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Fixed wrong return values when enpoints are roots in Brent solver with a user provided initial guess 

JIRA: MATH-344

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@915522 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Luc Maisonobe 2010-02-23 21:09:25 +00:00
parent f6dd42b4fc
commit a0b4b4b798
3 changed files with 15 additions and 4 deletions
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4
src/main/java/org/apache/commons/math/analysis/solvers/BrentSolver.java
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@ -112,7 +112,7 @@ public class BrentSolver extends UnivariateRealSolverImpl {
// return the first endpoint if it is good enough
double yMin = f.value(min);
if (Math.abs(yMin) <= functionValueAccuracy) {
setResult(yMin, 0);
setResult(min, 0);
return result;
}
@ -124,7 +124,7 @@ public class BrentSolver extends UnivariateRealSolverImpl {
// return the second endpoint if it is good enough
double yMax = f.value(max);
if (Math.abs(yMax) <= functionValueAccuracy) {
setResult(yMax, 0);
setResult(max, 0);
return result;
}

4
src/site/xdoc/changes.xml
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@ -39,6 +39,10 @@ The <action> type attribute can be add,update,fix,remove.
</properties>
<body>
<release version="2.1" date="TBD" description="TBD">
<action dev="luc" type="fix" issue="MATH-344" >
Fixed wrong return values when enpoints are roots in Brent solver with
a user provided initial guess
</action>
<action dev="luc" type="fix" issue="MATH-343" >
Fixed a missing bracketing check of initial interval in Brent solver.
</action>

11
src/test/java/org/apache/commons/math/analysis/solvers/BrentSolverTest.java
View File

@ -308,10 +308,17 @@ public final class BrentSolverTest extends TestCase {
// endpoint is root
double result = solver.solve(f, Math.PI, 4);
assertEquals(result, Math.PI, solver.getAbsoluteAccuracy());
assertEquals(Math.PI, result, solver.getAbsoluteAccuracy());
result = solver.solve(f, 3, Math.PI);
assertEquals(result, Math.PI, solver.getAbsoluteAccuracy());
assertEquals(Math.PI, result, solver.getAbsoluteAccuracy());
result = solver.solve(f, Math.PI, 4, 3.5);
assertEquals(Math.PI, result, solver.getAbsoluteAccuracy());
result = solver.solve(f, 3, Math.PI, 3.07);
assertEquals(Math.PI, result, solver.getAbsoluteAccuracy());
}
public void testBadEndpoints() throws Exception {