include/tenzr/modules/optim/lion.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_LION_H_
#define TENZR_MODULES_OPTIM_LION_H_

#include <string>
#include <unordered_map>

#include "tenzr/modules/optim/schedule.h"
#include "tenzr/modules/optim/transform.h"

namespace tenzr::optim {

  class Lion : public GradientTransformation {
   public:
    explicit Lion(double lr = 1.0e-4, double beta1 = 0.9, double beta2 = 0.99, double weight_decay = 0.0, ScheduleFn schedule = nullptr);

    OptState Init(const std::unordered_map<std::string, Tensor>& params) override;

    std::unordered_map<std::string, Tensor> Update(const std::unordered_map<std::string, Tensor>& grads, OptState& state,
                                                   const std::unordered_map<std::string, Tensor>& params) override;

    double Lr() const { return lr_; }
    double Beta1() const { return beta1_; }
    double Beta2() const { return beta2_; }
    double WeightDecay() const { return weight_decay_; }

   private:
    double lr_;
    double beta1_;
    double beta2_;
    double weight_decay_;
    ScheduleFn schedule_;
  };

}  // namespace tenzr::optim

#endif  // TENZR_MODULES_OPTIM_LION_H_