//  [java]
    protected UnivariatePointValuePair doOptimize() {
        final boolean isMinim = getGoalType() == GoalType.MINIMIZE;
        final double lo = getMin();
        final double mid = getStartValue();
        final double hi = getMax();
        final ConvergenceChecker<UnivariatePointValuePair> checker
            = getConvergenceChecker();
        double a;
        double b;
        if (lo < hi) {
            a = lo;
            b = hi;
        } else {
            a = hi;
            b = lo;
        }
        double x = mid;
        double v = x;
        double w = x;
        double d = 0;
        double e = 0;
        double fx = computeObjectiveValue(x);
        if (!isMinim) {
            fx = -fx;
        }
        double fv = fx;
        double fw = fx;
        UnivariatePointValuePair previous = null;
        UnivariatePointValuePair current
            = new UnivariatePointValuePair(x, isMinim ? fx : -fx);
        int iter = 0;
        while (true) {
            final double m = 0.5 * (a + b);
            final double tol1 = relativeThreshold * FastMath.abs(x) + absoluteThreshold;
            final double tol2 = 2 * tol1;
            final boolean stop = FastMath.abs(x - m) <= tol2 - 0.5 * (b - a);
            if (!stop) {
                double p = 0;
                double q = 0;
                double r = 0;
                double u = 0;
                if (FastMath.abs(e) > tol1) { 
                    r = (x - w) * (fx - fv);
                    q = (x - v) * (fx - fw);
                    p = (x - v) * q - (x - w) * r;
                    q = 2 * (q - r);
                    if (q > 0) {
                        p = -p;
                    } else {
                        q = -q;
                    }
                    r = e;
                    e = d;
                    if (p > q * (a - x) &&
                        p < q * (b - x) &&
                        FastMath.abs(p) < FastMath.abs(0.5 * q * r)) {
                        d = p / q;
                        u = x + d;
                        if (u - a < tol2 || b - u < tol2) {
                            if (x <= m) {
                                d = tol1;
                            } else {
                                d = -tol1;
                            }
                        }
                    } else {
                        if (x < m) {
                            e = b - x;
                        } else {
                            e = a - x;
                        }
                        d = GOLDEN_SECTION * e;
                    }
                } else {
                    if (x < m) {
                        e = b - x;
                    } else {
                        e = a - x;
                    }
                    d = GOLDEN_SECTION * e;
                }
                if (FastMath.abs(d) < tol1) {
                    if (d >= 0) {
                        u = x + tol1;
                    } else {
                        u = x - tol1;
                    }
                } else {
                    u = x + d;
                }
                double fu = computeObjectiveValue(u);
                if (!isMinim) {
                    fu = -fu;
                }
                previous = current;
                current = new UnivariatePointValuePair(u, isMinim ? fu : -fu);
                if (checker != null) {
                    if (checker.converged(iter, previous, current)) {
                        return best(current, previous, isMinim);
                    }
                }
                if (fu <= fx) {
                    if (u < x) {
                        b = x;
                    } else {
                        a = x;
                    }
                    v = w;
                    fv = fw;
                    w = x;
                    fw = fx;
                    x = u;
                    fx = fu;
                } else {
                    if (u < x) {
                        a = u;
                    } else {
                        b = u;
                    }
                    if (fu <= fw ||
                        Precision.equals(w, x)) {
                        v = w;
                        fv = fw;
                        w = u;
                        fw = fu;
                    } else if (fu <= fv ||
                               Precision.equals(v, x) ||
                               Precision.equals(v, w)) {
                        v = u;
                        fv = fu;
                    }
                }
            } else { 
                return
                            best(current,
                                 previous,
                            isMinim);
            }
            ++iter;
        }
    }