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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <cstddef>
namespace resource_coordinator {
// This class is an implementation of an exponential moving average,
// as described in
class ExponentialMovingAverage {
// Create a new moving average with |alpha| sample weight factor.
// 0.0 < |alpha| < 1.0.
explicit ExponentialMovingAverage(float alpha);
// Append a datum to the moving average.
void AppendDatum(float datum);
// Prepend a datum to the moving average.
// This is generally only used once to update the average with the average
// from a string of datums from a previous session or the like.
void PrependDatum(float datum);
// Set to no datums, zero value.
void Clear();
// Accessors.
float alpha() const { return alpha_; }
float value() const { return value_; }
size_t num_datums() const { return num_datums_; }
// The sample weight.
const float alpha_;
// The first datum.
float first_datum_ = 0.0;
// The current value of the moving average.
float value_ = 0.0;
// The number of datums added to this average.
size_t num_datums_ = 0;
} // namespace resource_coordinator