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# Template Class Int8Calibrator

- Defined in File ptq.h

## Inheritance Relationships

### Base Type

- `private Algorithm`

## Class Documentation

template < typename Algorithm , typename DataLoaderUniquePtr >
class torch_tensorrt :: ptq :: Int8Calibrator : private Algorithm

  Generic Int8Calibrator implementation based on a specified TensorRT calibration algorithm and a LibTorch DataLoader.

  tparam Algorithm

    class nvinfer1::IInt8Calibrator (Default: nvinfer1::IInt8EntropyCalibrator2) - Algorithm to use

  tparam DataLoaderUniquePtr

    std::unique_ptr<torch::data::DataLoader> - DataLoader type

  Public Functions

  inline Int8Calibrator ( DataLoaderUniquePtr dataloader , const std :: string & cache_file_path , bool use_cache )

    Construct a new Int8Calibrator object.

    Using the provided DataLoader, construct a calibrator that can be used for PTQ with Torch-TensorRT

    Parameters

      - dataloader – std::unqiue_ptr<torch::data::DataLoader> - A unique pointer to the DataLoader, should be what is returned from the make_data_loader factory

      - cache_file_path – const std::string& - A path to store / find the calibration cache

      - use_cache – : bool - Whether to use the cache (if it exists)

  inline int getBatchSize ( ) const noexcept override

    Get the Batch Size for the next batch (always 1 due to issues with TRT and explicit batch)

    Returns

      int

  inline bool getBatch ( void * bindings [ ] , const char * names [ ] , int nbBindings ) noexcept override

    Get the next Batch.

    Parameters

      - bindings – void*[] - An array of binding pointers (fed in from TensorRT calibrator), these buffers should be filed with batch data for each input

      - names – const char*[] - Names of bindings

      - nbBindings – int - Number of bindings

    Returns

      true - There is a new batch for the calibrator to consume

    Returns

      false - There is not a new batch for the calibrator to consume

  inline const void * readCalibrationCache ( size_t & length ) noexcept override

    Read calibration cache.

    How to read from the calibration cache, only enabled if use_cache is set

    Parameters

      length –

    Returns

      const void* - Pointer to cache data

  inline void writeCalibrationCache ( const void * cache , size_t length ) noexcept override

    Write calibration cache.

    Write a the calibration cache provided by TensorRT to a specified file

    Parameters

      - cache – const void* - cache data

      - length – size_t - length of cache

  inline operator nvinfer1 :: IInt8Calibrator * ( )

    operator to cast to nvinfer1::IInt8Calibrator*

    Convience function to convert to a IInt8Calibrator* to easily be assigned to the ptq_calibrator field in CompileSpec

    Returns

      nvinfer1::IInt8Calibrator*