libcore/include/sirikata/core/util/EWA.hpp

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/*  Sirikata
 *  EWA.hpp
 *
 *  Copyright (c) 2009, Ewen Cheslack-Postava
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  * Neither the name of Sirikata nor the names of its contributors may
 *    be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 */
#ifndef _SIRIKATA_LIBCORE_EWA_HPP_
#define _SIRIKATA_LIBCORE_EWA_HPP_

namespace Sirikata {

template<typename ValType>
class EWA {
public:
    EWA(float alpha)
     : mAlpha(alpha)
    {}

    void sample(const ValType& _s) {
        mEWA = (_s * mAlpha) + (mEWA * (1.f-mAlpha));
    }

    ValType value() const {
        return mEWA;
    }
private:
    float mAlpha;
    ValType mEWA;
};

} // namespace Sirikata

#endif //_SIRIKATA_LIBCORE_EWA_HPP_