// modified from https://github.com/NVIDIA/apex/blob/master/csrc/multi_tensor_adam.cu
#include <torch/extension.h>

void multi_tensor_scale_cuda(
  int chunk_size,
  at::Tensor noop_flag,
  std::vector<std::vector<at::Tensor>> tensor_lists,
  float scale);

void multi_tensor_sgd_cuda(
    int chunk_size,
    at::Tensor noop_flag,
    std::vector<std::vector<at::Tensor>> tensor_lists,
    float wd,
    float momentum,
    float dampening,
    float lr,
    bool nesterov,
    bool first_run,
    bool wd_after_momentum,
    float scale);

void multi_tensor_adam_cuda(
    int chunk_size,
    at::Tensor noop_flag,
    std::vector<std::vector<at::Tensor>> tensor_lists,
    const float lr,
    const float beta1,
    const float beta2,
    const float epsilon,
    const int step,
    const int mode,
    const int bias_correction,
    const float weight_decay);

void multi_tensor_lamb_cuda(
    int chunk_size,
    at::Tensor noop_flag,
    std::vector<std::vector<at::Tensor>> tensor_lists,
    const float lr,
    const float beta1,
    const float beta2,
    const float epsilon,
    const int step,
    const int bias_correction,
    const float weight_decay,
    const int grad_averaging,
    const int mode,
    at::Tensor global_grad_norm,
    const float max_grad_norm,
    at::optional<bool> use_nvlamb_python);

std::tuple<at::Tensor, at::Tensor> multi_tensor_l2norm_cuda(
    int chunk_size,
    at::Tensor noop_flag,
    std::vector<std::vector<at::Tensor>> tensor_lists,
    at::optional<bool> per_tensor_python);

PYBIND11_MODULE(TORCH_EXTENSION_NAME, m)
{
    m.def("multi_tensor_scale", &multi_tensor_scale_cuda,
        "Fused overflow check + scale for a list of contiguous tensors");
    m.def("multi_tensor_sgd", &multi_tensor_sgd_cuda,
          "Fused SGD optimizer for list of contiguous tensors");
    m.def("multi_tensor_adam", &multi_tensor_adam_cuda,
          "Compute and apply gradient update to parameters for Adam optimizer");
    m.def("multi_tensor_lamb", &multi_tensor_lamb_cuda,
          "Computes and apply update for LAMB optimizer");
    m.def("multi_tensor_l2norm", &multi_tensor_l2norm_cuda,
          "Computes L2 norm for a list of contiguous tensors");
}