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prevent root bracketing to be attempted outside of search interval 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1144887 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Luc Maisonobe 2011-07-10 16:04:51 +00:00
parent fef1366f09
commit f31af98c0d
1 changed files with 6 additions and 6 deletions
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12
src/main/java/org/apache/commons/math/analysis/solvers/UnivariateRealSolverUtils.java
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@ -104,14 +104,14 @@ public class UnivariateRealSolverUtils {
// find a very small interval bracketing the root // find a very small interval bracketing the root
final double step = FastMath.max(bracketing.getAbsoluteAccuracy(), final double step = FastMath.max(bracketing.getAbsoluteAccuracy(),
FastMath.abs(baseRoot * bracketing.getRelativeAccuracy())); FastMath.abs(baseRoot * bracketing.getRelativeAccuracy()));
double xLo = baseRoot - step; double xLo = FastMath.max(min, baseRoot - step);
double fLo = f.value(xLo); double fLo = f.value(xLo);
double xHi = baseRoot + step; double xHi = FastMath.min(max, baseRoot + step);
double fHi = f.value(xHi); double fHi = f.value(xHi);
int remainingEval = maxEval - 2; int remainingEval = maxEval - 2;
while ((remainingEval > 0) && (xLo >= min) && (xHi <= max)) { while (remainingEval > 0) {
if ((fLo > 0 && fHi < 0) || (fLo < 0 && fHi > 0)) { if ((fLo >= 0 && fHi <= 0) || (fLo <= 0 && fHi >= 0)) {
// compute the root on the selected side // compute the root on the selected side
return bracketing.solve(remainingEval, f, xLo, xHi, baseRoot, allowedSolutions); return bracketing.solve(remainingEval, f, xLo, xHi, baseRoot, allowedSolutions);
} }
@ -141,14 +141,14 @@ public class UnivariateRealSolverUtils {
// update the lower bound // update the lower bound
if (changeLo) { if (changeLo) {
xLo -= step; xLo = FastMath.max(min, xLo - step);
fLo = f.value(xLo); fLo = f.value(xLo);
remainingEval--; remainingEval--;
} }
// update the higher bound // update the higher bound
if (changeHi) { if (changeHi) {
xHi += step; xHi = FastMath.min(max, xHi + step);
fHi = f.value(xHi); fHi = f.value(xHi);
remainingEval--; remainingEval--;
} }