/*

 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "gc/g1/g1Predictions.hpp"

#ifndef PRODUCT

void G1Predictions::test() {

  double const epsilon = 1e-6;

  {

    // Some basic formula tests with confidence = 0.0

    G1Predictions predictor(0.0);

    TruncatedSeq s;

    double p0 = predictor.get_new_prediction(&s);

    assert(p0 < epsilon, "Initial prediction of empty sequence must be 0.0 but is %f", p0);

    s.add(5.0);

    double p1 = predictor.get_new_prediction(&s);

    assert(fabs(p1 - 5.0) < epsilon, "Prediction should be 5.0 but is %f", p1);

    for (int i = 0; i < 40; i++) {

      s.add(5.0);

    }

    double p2 = predictor.get_new_prediction(&s);

    assert(fabs(p2 - 5.0) < epsilon, "Prediction should be 5.0 but is %f", p1);

  }

  {

    // The following tests checks that the initial predictions are based on the

    // average of the sequence and not on the stddev (which is 0).

    G1Predictions predictor(0.5);

    TruncatedSeq s;

    s.add(1.0);

    double p1 = predictor.get_new_prediction(&s);

    assert(p1 > 1.0, "First prediction must be larger than average, but avg is %f and prediction %f", s.davg(), p1);

    s.add(1.0);

    double p2 = predictor.get_new_prediction(&s);

    assert(p2 < p1, "First prediction must be larger than second, but they are %f %f", p1, p2);

    s.add(1.0);

    double p3 = predictor.get_new_prediction(&s);

    assert(p3 < p2, "Second prediction must be larger than third, but they are %f %f", p2, p3);

    s.add(1.0);

    s.add(1.0); // Five elements are now in the sequence.

    double p5 = predictor.get_new_prediction(&s);

    assert(p5 < p3, "Fifth prediction must be smaller than third, but they are %f %f", p3, p5);

    assert(fabs(p5 - 1.0) < epsilon, "Prediction must be 1.0+epsilon, but is %f", p5);

  }

  {

    // The following tests checks that initially prediction based on the average is

    // used, that gets overridden by the stddev prediction at the end.

    G1Predictions predictor(0.5);

    TruncatedSeq s;

    s.add(0.5);

    double p1 = predictor.get_new_prediction(&s);

    assert(p1 > 0.5, "First prediction must be larger than average, but avg is %f and prediction %f", s.davg(), p1);

    s.add(0.2);

    double p2 = predictor.get_new_prediction(&s);

    assert(p2 < p1, "First prediction must be larger than second, but they are %f %f", p1, p2);

    s.add(0.5);

    double p3 = predictor.get_new_prediction(&s);

    assert(p3 < p2, "Second prediction must be larger than third, but they are %f %f", p2, p3);

    s.add(0.2);

    s.add(2.0);

    double p5 = predictor.get_new_prediction(&s);

    assert(p5 > p3, "Fifth prediction must be bigger than third, but they are %f %f", p3, p5);

  }

}

void TestPredictions_test() {

  G1Predictions::test();

}

#endif