custom_vjp.h¶

Namespaces¶

Name
tenzr
tenzr::txpr

Classes¶

	Name
struct	tenzr::txpr::CustomVJPRule A forward/backward rule pair defining the gradient of an operation that autodiff cannot derive on its own.
class	tenzr::txpr::CustomVJPRegistry Process-wide registry mapping operation names to custom VJP rules.
class	tenzr::txpr::CustomVJPFunction Callable wrapper that applies a function decorated with a registered custom VJP rule.

Source code¶

// 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_TXPR_CUSTOM_VJP_H_
#define TENZR_TXPR_CUSTOM_VJP_H_

#include <functional>
#include <memory>
#include <string>
#include <string_view>
#include <unordered_map>
#include <utility>

#include "tenzr/array.h"
#include "tenzr/common/export.h"

namespace tenzr::txpr {

  struct CustomVJPRule {
    std::function<std::pair<Array, Array>(const Array&)> fwd;
    std::function<Array(const Array&, const Array&)> bwd;
  };

  class TENZR_API CustomVJPRegistry {
   public:
    static CustomVJPRegistry& Instance();

    void RegisterRule(std::string name, CustomVJPRule rule);
    [[nodiscard]] bool HasRule(std::string_view name) const;
    [[nodiscard]] const CustomVJPRule& GetRule(std::string_view name) const;

   private:
    CustomVJPRegistry() = default;
    std::unordered_map<std::string, CustomVJPRule> rules_;
  };

  class TENZR_API CustomVJPFunction {
   public:
    CustomVJPFunction(std::string name, std::function<Array(const Array&)> fn, std::function<std::pair<Array, Array>(const Array&)> fwd,
                      std::function<Array(const Array&, const Array&)> bwd);

    Array operator()(const Array& x) const;

   private:
    std::string name_;
    std::function<Array(const Array&)> fn_;
  };

  [[nodiscard]] TENZR_API CustomVJPFunction CustomVjp(std::string name, std::function<Array(const Array&)> fn,
                                                      std::function<std::pair<Array, Array>(const Array&)> fwd,
                                                      std::function<Array(const Array&, const Array&)> bwd);

  TENZR_API void RegisterCustomVjp(const std::string& name, std::function<Array(const Array&, const Array&)> bwd_fn);

  TENZR_API void SetGradTracingActive(bool active) noexcept;
  [[nodiscard]] TENZR_API bool IsGradTracingActive() noexcept;

}  // namespace tenzr::txpr

namespace tenzr {
  using txpr::CustomVjp;
  using txpr::CustomVJPFunction;
  using txpr::CustomVJPRegistry;
  using txpr::RegisterCustomVjp;
}  // namespace tenzr

#endif  // TENZR_TXPR_CUSTOM_VJP_H_