PyMethodBase.cxx

Go to the documentation of this file.

// @(#)root/tmva/pymva $Id$
// Authors: Omar Zapata, Lorenzo Moneta, Sergei Gleyzer 2015, Stefan Wunsch 2017
 
/**********************************************************************************
 * Project: TMVA - a Root-integrated toolkit for multivariate data analysis       *
 * Package: TMVA                                                                  *
 * Class  : PyMethodBase                                                          *
 *                                                                                *
 * Description:                                                                   *
 *      Virtual base class for all MVA method based on python                     *
 *                                                                                *
 **********************************************************************************/
 
#include <Python.h> // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
#include <TMVA/PyMethodBase.h>
 
#include "TMVA/DataSet.h"
#include "TMVA/DataSetInfo.h"
#include "TMVA/MsgLogger.h"
#include "TMVA/Results.h"
#include "TMVA/Timer.h"
#include "TMVA/Tools.h"
 
#include "TSystem.h"
 
#define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION
#include <numpy/arrayobject.h>
 
using namespace TMVA;
 
namespace TMVA {
namespace Internal {
class PyGILRAII {
   PyGILState_STATE m_GILState;
 
public:
   PyGILRAII() : m_GILState(PyGILState_Ensure()) {}
   ~PyGILRAII() { PyGILState_Release(m_GILState); }
};
} // namespace Internal
 
/// get current Python executable used by ROOT
TString Python_Executable() {
   TString python_version = gSystem->GetFromPipe("root-config --python-version");
   if (python_version.IsNull()) {
      TMVA::gTools().Log() << kFATAL << "Can't find a valid Python version used to build ROOT" << Endl;
      return nullptr;
   }
#ifdef _MSC_VER
   // on Windows there is a space before the version and the executable is python.exe
   // for both versions of Python
   python_version.ReplaceAll(" ", "");
   if (python_version[0] == '2' || python_version[0] == '3')
      return "python";
#endif
   if (python_version[0] == '2')
      return "python";
   else if (python_version[0] == '3')
      return "python3";
 
   TMVA::gTools().Log() << kFATAL << "Invalid Python version used to build ROOT : " << python_version << Endl;
   return nullptr;
}
 
} // namespace TMVA
 
ClassImp(PyMethodBase);
 
// NOTE: Introduce here nothing that breaks if multiple instances
// of the same method share these objects, e.g., the local namespace.
PyObject *PyMethodBase::fModuleBuiltin = NULL;
PyObject *PyMethodBase::fEval = NULL;
PyObject *PyMethodBase::fOpen = NULL;
 
PyObject *PyMethodBase::fModulePickle = NULL;
PyObject *PyMethodBase::fPickleDumps = NULL;
PyObject *PyMethodBase::fPickleLoads = NULL;
 
PyObject *PyMethodBase::fMain = NULL;
PyObject *PyMethodBase::fGlobalNS = NULL;
 
///////////////////////////////////////////////////////////////////////////////
 
PyMethodBase::PyMethodBase(const TString &jobName, Types::EMVA methodType, const TString &methodTitle, DataSetInfo &dsi,
                           const TString &theOption)
   : MethodBase(jobName, methodType, methodTitle, dsi, theOption),
      fClassifier(NULL)
{
   if (!PyIsInitialized()) {
      PyInitialize();
   }
 
   // Set up private local namespace for each method instance
   fLocalNS = PyDict_New();
   if (!fLocalNS) {
      Log() << kFATAL << "Can't init local namespace" << Endl;
   }
}
 
///////////////////////////////////////////////////////////////////////////////
 
PyMethodBase::PyMethodBase(Types::EMVA methodType,
                           DataSetInfo &dsi,
                           const TString &weightFile): MethodBase(methodType, dsi, weightFile),
   fClassifier(NULL)
{
   if (!PyIsInitialized()) {
      PyInitialize();
   }
 
   // Set up private local namespace for each method instance
   fLocalNS = PyDict_New();
   if (!fLocalNS) {
      Log() << kFATAL << "Can't init local namespace" << Endl;
   }
}
 
///////////////////////////////////////////////////////////////////////////////
 
PyMethodBase::~PyMethodBase()
{
   // should we delete here fLocalNS ?
}
 
///////////////////////////////////////////////////////////////////////////////
/// Evaluate Python code
///
/// \param[in] code Python code as string
/// \return Python object from evaluation of code line
///
/// Take a Python code as input and evaluate it in the local namespace. Then,
/// return the result as Python object.
 
PyObject *PyMethodBase::Eval(TString code)
{
   if(!PyIsInitialized()) PyInitialize();
   PyObject *pycode = Py_BuildValue("(sOO)", code.Data(), fGlobalNS, fLocalNS);
   PyObject *result = PyObject_CallObject(fEval, pycode);
   Py_DECREF(pycode);
   return result;
}
 
///////////////////////////////////////////////////////////////////////////////
/// Initialize Python interpreter
///
/// NOTE: We introduce a shared global namespace `fGlobalNS`, but using
/// a private local namespace `fLocalNS`. This prohibits the interference
/// of instances of the same method with the same factory, e.g., by overriding
/// variables in the same local namespace.
 
void PyMethodBase::PyInitialize()
{
   TMVA::MsgLogger Log;
 
   bool pyIsInitialized = PyIsInitialized();
   if (!pyIsInitialized) {
      Py_Initialize();
   }
 
   TMVA::Internal::PyGILRAII raii;
   if (!pyIsInitialized) {
      _import_array();
   }
 
   // note fMain is a borrowed reference
   fMain = PyImport_AddModule("__main__");
   if (!fMain) {
      Log << kFATAL << "Can't import __main__" << Endl;
      Log << Endl;
   }
   Py_INCREF(fMain);
 
   fGlobalNS = PyModule_GetDict(fMain);
   if (!fGlobalNS) {
      Log << kFATAL << "Can't init global namespace" << Endl;
      Log << Endl;
   }
   Py_INCREF(fGlobalNS);
 
   #if PY_MAJOR_VERSION < 3
   //preparing objects for eval
   PyObject *bName =  PyUnicode_FromString("__builtin__");
   // Import the file as a Python module.
   // returns a new reference
   fModuleBuiltin = PyImport_Import(bName);
   if (!fModuleBuiltin) {
      Log << kFATAL << "Can't import __builtin__" << Endl;
      Log << Endl;
   }
   #else
   //preparing objects for eval
   PyObject *bName =  PyUnicode_FromString("builtins");
   // Import the file as a Python module.
   fModuleBuiltin = PyImport_Import(bName);
   if (!fModuleBuiltin) {
      Log << kFATAL << "Can't import builtins" << Endl;
      Log << Endl;
   }
   #endif
 
   // note mDict is a borrowed reference
   PyObject *mDict = PyModule_GetDict(fModuleBuiltin);
   fEval = PyDict_GetItemString(mDict, "eval");
   fOpen = PyDict_GetItemString(mDict, "open");
    // fEval and fOpen are borrowed referencers and we need to keep them alive
   if (fEval) Py_INCREF(fEval);
   if (fOpen) Py_INCREF(fOpen);
 
   // bName is a new reference (from PyUnicode_FromString)
   Py_DECREF(bName);
 
   //preparing objects for pickle
   PyObject *pName = PyUnicode_FromString("pickle");
   // Import the file as a Python module.
   // return object is a new reference !
   fModulePickle = PyImport_Import(pName);
   if (!fModulePickle) {
      Log << kFATAL << "Can't import pickle" << Endl;
      Log << Endl;
   }
   PyObject *pDict = PyModule_GetDict(fModulePickle);
   // note the following return objects are borrowed references
   fPickleDumps = PyDict_GetItemString(pDict, "dump");
   fPickleLoads = PyDict_GetItemString(pDict, "load");
   if (fPickleDumps) Py_INCREF(fPickleDumps);
   if (fPickleLoads) Py_INCREF(fPickleLoads);
 
   Py_DECREF(pName);
}
 
///////////////////////////////////////////////////////////////////////////////
// Finalize Python interpreter
 
void PyMethodBase::PyFinalize()
{
   if (fEval) Py_DECREF(fEval);
   if (fOpen) Py_DECREF(fOpen);
   if (fModuleBuiltin) Py_DECREF(fModuleBuiltin);
   if (fPickleDumps) Py_DECREF(fPickleDumps);
   if (fPickleLoads) Py_DECREF(fPickleLoads);
   if(fMain) Py_DECREF(fMain);//objects fGlobalNS and fLocalNS will be free here
   if (fGlobalNS) Py_DECREF(fGlobalNS);
   Py_Finalize();
}
 
///////////////////////////////////////////////////////////////////////////////
/// Check Python interpreter initialization status
///
/// \return Boolean whether interpreter is initialized
 
int PyMethodBase::PyIsInitialized()
{
   if (!Py_IsInitialized()) return kFALSE;
   if (!fEval) return kFALSE;
   if (!fModuleBuiltin) return kFALSE;
   if (!fPickleDumps) return kFALSE;
   if (!fPickleLoads) return kFALSE;
   return kTRUE;
}
 
///////////////////////////////////////////////////////////////////////////////
/// Serialize Python object
///
/// \param[in] path Path where object is written to file
/// \param[in] obj Python object
///
/// The input Python object is serialized and written to a file. The Python
/// module `pickle` is used to do so.
 
void PyMethodBase::Serialize(TString path, PyObject *obj)
{
   if(!PyIsInitialized()) PyInitialize();
 
   PyObject *file_arg = Py_BuildValue("(ss)", path.Data(),"wb");
   PyObject *file = PyObject_CallObject(fOpen,file_arg);
   PyObject *model_arg = Py_BuildValue("(OO)", obj,file);
   PyObject *model_data = PyObject_CallObject(fPickleDumps , model_arg);
 
   Py_DECREF(file_arg);
   Py_DECREF(file);
   Py_DECREF(model_arg);
   Py_DECREF(model_data);
}
 
///////////////////////////////////////////////////////////////////////////////
/// Unserialize Python object
///
/// \param[in] path Path to serialized Python object
/// \param[in] obj Python object where the unserialized Python object is loaded
///  \return Error code
 
Int_t PyMethodBase::UnSerialize(TString path, PyObject **obj)
{
   // Load file
   PyObject *file_arg = Py_BuildValue("(ss)", path.Data(),"rb");
   PyObject *file = PyObject_CallObject(fOpen,file_arg);
   if(!file) return 1;
 
   // Load object from file using pickle
   PyObject *model_arg = Py_BuildValue("(O)", file);
   *obj = PyObject_CallObject(fPickleLoads , model_arg);
   if(!obj) return 2;
 
   Py_DECREF(file_arg);
   Py_DECREF(file);
   Py_DECREF(model_arg);
 
   return 0;
}
 
///////////////////////////////////////////////////////////////////////////////
/// Execute Python code from string
///
/// \param[in] code Python code as string
/// \param[in] errorMessage Error message which shall be shown if the execution fails
/// \param[in] start Start symbol
///
/// Helper function to run python code from string in local namespace with
/// error handling
/// `start` defines the start symbol defined in PyRun_String (Py_eval_input,
/// Py_single_input, Py_file_input)
 
void PyMethodBase::PyRunString(TString code, TString errorMessage, int start) {
   fPyReturn = PyRun_String(code, start, fGlobalNS, fLocalNS);
   if (!fPyReturn) {
      Log() << kWARNING << "Failed to run python code: " << code << Endl;
      Log() << kWARNING << "Python error message:" << Endl;
      PyErr_Print();
      Log() << kFATAL << errorMessage << Endl;
   }
}
 
///////////////////////////////////////////////////////////////////////////////
/// Execute Python code from string
///
/// \param[in] code Python code as string
/// \param[in] globalNS Global Namespace for Python Session
/// \param[in] localNS Local Namespace for Python Session
///
/// Overloaded static Helper function to run python code
/// from string and throw runtime error if the Python session
/// is unable to execute the code
 
void PyMethodBase::PyRunString(TString code, PyObject *globalNS, PyObject *localNS){
   PyObject *fPyReturn = PyRun_String(code, Py_single_input, globalNS, localNS);
   if (!fPyReturn) {
      std::cout<<"\nPython error message:\n";
      PyErr_Print();
      throw std::runtime_error("\nFailed to run python code: "+code);
   }
}
 
///////////////////////////////////////////////////////////////////////////////
/// Returns `const char*` from Python string in PyObject
///
/// \param[in] string Python String object
/// \return String representation in `const char*`
 
const char* PyMethodBase::PyStringAsString(PyObject* string){
   PyObject* encodedString = PyUnicode_AsUTF8String(string);
   const char* cstring = PyBytes_AsString(encodedString);
   return cstring;
}
 
//////////////////////////////////////////////////////////////////////////////////
/// \brief Utility function which retrieves and returns the values of the Tuple
///        object as a vector of size_t
///
/// \param[in] tupleObject Python Tuple object
/// \return vector of tuple members
 
std::vector<size_t> PyMethodBase::GetDataFromTuple(PyObject* tupleObject){
   std::vector<size_t>tupleVec;
   for(Py_ssize_t tupleIter=0;tupleIter<PyTuple_Size(tupleObject);++tupleIter){
      auto itemObj = PyTuple_GetItem(tupleObject,tupleIter);
      if (itemObj == Py_None)
         tupleVec.push_back(0);  // case shape is for example (None,2,3)
      else
         tupleVec.push_back((size_t)PyLong_AsLong(itemObj));
   }
   return tupleVec;
}
 
//////////////////////////////////////////////////////////////////////////////////
/// \brief Utility function which retrieves and returns the values of the List
///        object as a vector of size_t
///
/// \param[in] listObject Python List object
/// \return vector of list members
 
std::vector<size_t> PyMethodBase::GetDataFromList(PyObject* listObject){
   std::vector<size_t>listVec;
   for(Py_ssize_t listIter=0; listIter<PyList_Size(listObject);++listIter){
               listVec.push_back((size_t)PyLong_AsLong(PyList_GetItem(listObject,listIter)));
         }
   return listVec;
}
 
//////////////////////////////////////////////////////////////////////////////////
/// \brief Utility function which checks if a given key is present in a Python 
///        dictionary object and returns the associated value or throws runtime
///        error. This is to replace PyDict_GetItemWithError in Python 2.
///
/// \param[in] listObject Python Dict object
/// \return Associated value PyObject
PyObject* PyMethodBase::GetValueFromDict(PyObject* dict, const char* key){
   #if PY_MAJOR_VERSION >= 3   // using PyDict_GetItemWithError that is available only in Python3
   return PyDict_GetItemWithError(dict,PyUnicode_FromString(key));
   #else
   if(!PyDict_Contains(dict, PyUnicode_FromString(key))){
      throw std::runtime_error(std::string("Key ")+key+" does not exist in the dictionary.");
   } else {
      return PyDict_GetItemString(dict, key);
   }
   #endif
}