buggy files form Math #70

projects/Math/70/org/apache/commons/math/analysis/solvers/BisectionSolver.java

@@ -0,0 +1,109 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.math.analysis.solvers;
+
+import org.apache.commons.math.FunctionEvaluationException;
+import org.apache.commons.math.MaxIterationsExceededException;
+import org.apache.commons.math.analysis.UnivariateRealFunction;
+
+/**
+ * Implements the <a href="http://mathworld.wolfram.com/Bisection.html">
+ * bisection algorithm</a> for finding zeros of univariate real functions.
+ * <p>
+ * The function should be continuous but not necessarily smooth.</p>
+ *
+ * @version $Revision$ $Date$
+ */
+public class BisectionSolver extends UnivariateRealSolverImpl {
+
+    /**
+     * Construct a solver for the given function.
+     *
+     * @param f function to solve.
+     * @deprecated as of 2.0 the function to solve is passed as an argument
+     * to the {@link #solve(UnivariateRealFunction, double, double)} or
+     * {@link UnivariateRealSolverImpl#solve(UnivariateRealFunction, double, double, double)}
+     * method.
+     */
+    @Deprecated
+    public BisectionSolver(UnivariateRealFunction f) {
+        super(f, 100, 1E-6);
+    }
+
+    /**
+     * Construct a solver.
+     *
+     */
+    public BisectionSolver() {
+        super(100, 1E-6);
+    }
+
+    /** {@inheritDoc} */
+    @Deprecated
+    public double solve(double min, double max, double initial)
+        throws MaxIterationsExceededException, FunctionEvaluationException {
+        return solve(f, min, max);
+    }
+
+    /** {@inheritDoc} */
+    @Deprecated
+    public double solve(double min, double max)
+        throws MaxIterationsExceededException, FunctionEvaluationException {
+        return solve(f, min, max);
+    }
+
+    /** {@inheritDoc} */
+    public double solve(final UnivariateRealFunction f, double min, double max, double initial)
+        throws MaxIterationsExceededException, FunctionEvaluationException {
+        return solve(min, max);
+    }
+
+    /** {@inheritDoc} */
+    public double solve(final UnivariateRealFunction f, double min, double max)
+        throws MaxIterationsExceededException, FunctionEvaluationException {
+
+        clearResult();
+        verifyInterval(min,max);
+        double m;
+        double fm;
+        double fmin;
+
+        int i = 0;
+        while (i < maximalIterationCount) {
+            m = UnivariateRealSolverUtils.midpoint(min, max);
+           fmin = f.value(min);
+           fm = f.value(m);
+
+            if (fm * fmin > 0.0) {
+                // max and m bracket the root.
+                min = m;
+            } else {
+                // min and m bracket the root.
+                max = m;
+            }
+
+            if (Math.abs(max - min) <= absoluteAccuracy) {
+                m = UnivariateRealSolverUtils.midpoint(min, max);
+                setResult(m, i);
+                return m;
+            }
+            ++i;
+        }
+
+        throw new MaxIterationsExceededException(maximalIterationCount);
+    }
+}