include/tenzr/modules/optim/ema.h¶

// Copyright 2026 The Tenzr Project Authors
//
// SPDX-License-Identifier: Apache-2.0
//
// Licensed 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
//
//      https://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.

#ifndef TENZR_MODULES_OPTIM_EMA_H_
#define TENZR_MODULES_OPTIM_EMA_H_

#include <string>
#include <unordered_map>

#include "tenzr/frontend/tensor.h"

namespace tenzr::optim {

  class ExponentialMovingAverage {
   public:
    explicit ExponentialMovingAverage(const std::unordered_map<std::string, Tensor>& params, double decay = 0.999);

    void Update(const std::unordered_map<std::string, Tensor>& params);

    void ApplyShadow(std::unordered_map<std::string, Tensor>& params);

    void Restore(std::unordered_map<std::string, Tensor>& params);

    const std::unordered_map<std::string, Tensor>& ShadowParams() const { return shadow_params_; }

    double Decay() const { return decay_; }

   private:
    double decay_;
    std::unordered_map<std::string, Tensor> shadow_params_;
    std::unordered_map<std::string, Tensor> backup_params_;
  };

}  // namespace tenzr::optim

#endif  // TENZR_MODULES_OPTIM_EMA_H_