xgboost/src/rabit.h
2014-12-03 10:00:47 -08:00

121 lines
4.1 KiB
C++

#ifndef RABIT_RABIT_H
#define RABIT_RABIT_H
/*!
* \file rabit.h
* \brief This file defines unified Allreduce/Broadcast interface of rabit
* The actual implementation is redirected to rabit engine
* Code only using this header can also compiled with MPI Allreduce(with no fault recovery),
*
* \author Tianqi Chen, Ignacio Cano, Tianyi Zhou
*/
#include <string>
#include <vector>
#include "./engine.h"
/*! \brief namespace of rabit */
namespace rabit {
/*! \brief namespace of operator */
namespace op {
/*! \brief maximum value */
struct Max;
/*! \brief minimum value */
struct Min;
/*! \brief perform sum */
struct Sum;
/*! \brief perform bitwise OR */
struct BitOR;
} // namespace op
/*!
* \brief intialize the rabit module, call this once function before using anything
* \param argc number of arguments in argv
* \param argv the array of input arguments
*/
inline void Init(int argc, char *argv[]);
/*!
* \brief finalize the rabit engine, call this function after you finished all jobs
*/
inline void Finalize(void);
/*! \brief get rank of current process */
inline int GetRank(void);
/*! \brief get total number of process */
inline int GetWorldSize(void);
/*! \brief get name of processor */
inline std::string GetProcessorName(void);
/*!
* \brief broadcast an memory region to all others from root
* Example: int a = 1; Broadcast(&a, sizeof(a), root);
* \param sendrecv_data the pointer to send or recive buffer,
* \param size the size of the data
* \param root the root of process
*/
inline void Broadcast(void *sendrecv_data, size_t size, int root);
/*!
* \brief broadcast an std::vector<DType> to all others from root
* \param sendrecv_data the pointer to send or recive vector,
* for receiver, the vector does not need to be pre-allocated
* \param root the root of process
* \tparam DType the data type stored in vector, have to be simple data type
* that can be directly send by sending the sizeof(DType) data
*/
template<typename DType>
inline void Broadcast(std::vector<DType> *sendrecv_data, int root);
/*!
* \brief broadcast an std::string to all others from root
* \param sendrecv_data the pointer to send or recive vector,
* for receiver, the vector does not need to be pre-allocated
* \param root the root of process
*/
inline void Broadcast(std::string *sendrecv_data, int root);
/*!
* \brief perform in-place allreduce, on sendrecvbuf
* this function is NOT thread-safe
* Example Usage: the following code gives sum of the result
* vector<int> data(10);
* ...
* Allreduce<op::Sum>(&data[0], data.size());
* ...
* \param sendrecvbuf buffer for both sending and recving data
* \param count number of elements to be reduced
* \tparam OP see namespace op, reduce operator
* \tparam DType type of data
*/
template<typename OP, typename DType>
inline void Allreduce(DType *sendrecvbuf, size_t count);
/*!
* \brief load latest check point
* \param p_model pointer to the model
* \return the version number of check point loaded
* if returned version == 0, this means no model has been CheckPointed
* the p_model is not touched, user should do necessary initialization by themselves
*
* Common usage example:
* int iter = rabit::LoadCheckPoint(&model);
* if (iter == 0) model.InitParameters();
* for (i = iter; i < max_iter; ++i) {
* do many things, include allreduce
* rabit::CheckPoint(model);
* }
*
* \sa CheckPoint, VersionNumber
*/
inline int LoadCheckPoint(utils::ISerializable *p_model);
/*!
* \brief checkpoint the model, meaning we finished a stage of execution
* every time we call check point, there is a version number which will increase by one
*
* \param p_model pointer to the model
* \sa LoadCheckPoint, VersionNumber
*/
inline void CheckPoint(const utils::ISerializable &model);
/*!
* \return version number of current stored model,
* which means how many calls to CheckPoint we made so far
* \sa LoadCheckPoint, CheckPoint
*/
inline int VersionNumber(void);
} // namespace rabit
// implementation of template functions
#include "./rabit-inl.h"
#endif // RABIT_ALLREDUCE_H