diff --git a/bindings/pyroot_experimental/PyROOT/CMakeLists.txt b/bindings/pyroot_experimental/PyROOT/CMakeLists.txt
index b63f0f3b77178efb2ed5dd5aadd51d16d71de700..e2329f764a5df34bac173ee947e8277eaf9e42b9 100644
--- a/bindings/pyroot_experimental/PyROOT/CMakeLists.txt
+++ b/bindings/pyroot_experimental/PyROOT/CMakeLists.txt
@@ -11,6 +11,7 @@ set(sources
src/PyROOTWrapper.cxx
src/TTreePyz.cxx
src/PrettyPrintingPyz.cxx
+ src/ArrayInterfacePyz.cxx
)
file(COPY python/ROOT DESTINATION ${localruntimedir})
diff --git a/bindings/pyroot_experimental/PyROOT/python/ROOT/pythonization/_rvec.py b/bindings/pyroot_experimental/PyROOT/python/ROOT/pythonization/_rvec.py
new file mode 100644
index 0000000000000000000000000000000000000000..c302381a8992d4fae68c450a5a91f83fc575c977
--- /dev/null
+++ b/bindings/pyroot_experimental/PyROOT/python/ROOT/pythonization/_rvec.py
@@ -0,0 +1,51 @@
+from ROOT import pythonization
+from libROOTPython import GetEndianess, GetVectorDataPointer, GetSizeOfType
+
+_array_interface_dtypes = [
+ "float", "double", "int", "long", "unsigned int", "unsigned long"
+]
+
+_array_interface_dtype_map = {
+ "float": "f",
+ "double": "f",
+ "int": "i",
+ "long": "i",
+ "unsigned int": "u",
+ "unsigned long": "u"
+}
+
+
+def get_array_interface(self):
+ cppname = type(self).__cppname__
+ for dtype in _array_interface_dtypes:
+ if cppname.endswith("<{}>".format(dtype)):
+ dtype_numpy = _array_interface_dtype_map[dtype]
+ dtype_size = GetSizeOfType(dtype)
+ endianess = GetEndianess()
+ size = self.size()
+ pointer = GetVectorDataPointer(self, cppname)
+ return {
+ "shape": (size, ),
+ "typestr": "{}{}{}".format(endianess, dtype_numpy, dtype_size),
+ "version": 3,
+ "data": (pointer, False)
+ }
+
+
+def add_array_interface_property(klass, name):
+ if True in [
+ "<{}>".format(dtype) in name for dtype in _array_interface_dtypes
+ ]:
+ klass.__array_interface__ = property(get_array_interface)
+
+
+@pythonization
+def pythonize_rvec(klass, name):
+ # Parameters:
+ # klass: class to be pythonized
+ # name: string containing the name of the class
+
+ # Add numpy array interface
+ add_array_interface_property(klass, name)
+
+ return True
diff --git a/bindings/pyroot_experimental/PyROOT/python/ROOT/pythonization/_stl_vector.py b/bindings/pyroot_experimental/PyROOT/python/ROOT/pythonization/_stl_vector.py
new file mode 100644
index 0000000000000000000000000000000000000000..7cb7cef7b3da6eba94b87cb7e7e3973710c92690
--- /dev/null
+++ b/bindings/pyroot_experimental/PyROOT/python/ROOT/pythonization/_stl_vector.py
@@ -0,0 +1,15 @@
+from ROOT import pythonization
+from ROOT.pythonization._rvec import add_array_interface_property
+
+
+@pythonization
+def pythonize_stl_vector(klass, name):
+ # Parameters:
+ # klass: class to be pythonized
+ # name: string containing the name of the class
+
+ # Add numpy array interface
+ # NOTE: The pythonization is reused from ROOT::VecOps::RVec
+ add_array_interface_property(klass, name)
+
+ return True
diff --git a/bindings/pyroot_experimental/PyROOT/src/ArrayInterfacePyz.cxx b/bindings/pyroot_experimental/PyROOT/src/ArrayInterfacePyz.cxx
new file mode 100644
index 0000000000000000000000000000000000000000..4ce721edac302ce7b5f7584ab59c08425ec1cd20
--- /dev/null
+++ b/bindings/pyroot_experimental/PyROOT/src/ArrayInterfacePyz.cxx
@@ -0,0 +1,78 @@
+#include "CPyCppyy.h"
+#include "CPPInstance.h"
+#include "PyROOTPythonize.h"
+#include "RConfig.h"
+#include "TInterpreter.h"
+
+#include <sstream>
+
+////////////////////////////////////////////////////////////////////////////
+/// \brief Get size of C++ data-type
+/// \param[in] self Always null, since this is a module function.
+/// \param[in] args C++ data-type as Python string
+///
+/// This function returns the length of a C++ data-type in bytes
+/// as a Python integer.
+PyObject *PyROOT::GetSizeOfType(PyObject * /*self*/, PyObject *args)
+{
+ // Get name of data-type
+ PyObject *pydtype = PyTuple_GetItem(args, 0);
+ std::string dtype = CPyCppyy_PyUnicode_AsString(pydtype);
+
+ // Call interpreter to get size of data-type using `sizeof`
+ long size;
+ std::stringstream code;
+ code << "*((long*)" << &size << ") = (long)sizeof(" << dtype << ")";
+ gInterpreter->Calc(code.str().c_str());
+
+ // Return size of data-type as integer
+ PyObject *pysize = PyInt_FromLong(size);
+ return pysize;
+}
+
+////////////////////////////////////////////////////////////////////////////
+/// \brief Get pointer to the data of a vector
+/// \param[in] self Always null, since this is a module function.
+/// \param[in] args[0] Data-type of the C++ object as Python string
+/// \param[in] args[1] Python representation of the C++ object.
+///
+/// This function returns the pointer to the data of a vector as an Python
+/// integer.
+PyObject *PyROOT::GetVectorDataPointer(PyObject * /*self*/, PyObject *args)
+{
+ // Get pointer of C++ object
+ PyObject *pyobj = PyTuple_GetItem(args, 0);
+ auto instance = (CPyCppyy::CPPInstance *)(pyobj);
+ auto cppobj = instance->GetObject();
+
+ // Get name of C++ object as string
+ PyObject *pycppname = PyTuple_GetItem(args, 1);
+ std::string cppname = CPyCppyy_PyUnicode_AsString(pycppname);
+
+ // Call interpreter to get pointer to data (using `data` method)
+ long pointer;
+ std::stringstream code;
+ code << "*((long*)" << &pointer << ") = reinterpret_cast<long>(reinterpret_cast<" << cppname << "*>(" << cppobj
+ << ")->data())";
+ gInterpreter->Calc(code.str().c_str());
+
+ // Return pointer as integer
+ PyObject *pypointer = PyInt_FromLong(pointer);
+ return pypointer;
+}
+
+////////////////////////////////////////////////////////////////////////////
+/// \brief Get endianess of the system
+/// \param[in] self Always null, since this is a module function.
+/// \param[out] Endianess as Python string
+///
+/// This function returns endianess of the system as a Python integer. The
+/// return value is either '<' or '>' for little or big endian, respectively.
+PyObject *PyROOT::GetEndianess(PyObject * /* self */)
+{
+#ifdef R__BYTESWAP
+ return CPyCppyy_PyUnicode_FromString("<");
+#else
+ return CPyCppyy_PyUnicode_FromString(">");
+#endif
+}
diff --git a/bindings/pyroot_experimental/PyROOT/src/PyROOTModule.cxx b/bindings/pyroot_experimental/PyROOT/src/PyROOTModule.cxx
index 5c6db005adebeff31f09413e28c112fed8592827..a2cbbfa509e4ae6eb897f55dc2ee2becf83878c5 100644
--- a/bindings/pyroot_experimental/PyROOT/src/PyROOTModule.cxx
+++ b/bindings/pyroot_experimental/PyROOT/src/PyROOTModule.cxx
@@ -31,6 +31,12 @@ static PyMethodDef gPyROOTMethods[] = {{(char *)"PythonizeTTree", (PyCFunction)P
(char *)"Pythonizations for class TTree"},
{(char *)"AddPrettyPrintingPyz", (PyCFunction)PyROOT::AddPrettyPrintingPyz, METH_VARARGS,
(char *)"Add pretty printing pythonization"},
+ {(char *)"GetEndianess", (PyCFunction)PyROOT::GetEndianess, METH_NOARGS,
+ (char *)"Get endianess of the system"},
+ {(char *)"GetVectorDataPointer", (PyCFunction)PyROOT::GetVectorDataPointer, METH_VARARGS,
+ (char *)"Get pointer to data of vector"},
+ {(char *)"GetSizeOfType", (PyCFunction)PyROOT::GetSizeOfType, METH_VARARGS,
+ (char *)"Get size of data-type"},
{NULL, NULL, 0, NULL}};
#if PY_VERSION_HEX >= 0x03000000
diff --git a/bindings/pyroot_experimental/PyROOT/src/PyROOTPythonize.h b/bindings/pyroot_experimental/PyROOT/src/PyROOTPythonize.h
index c0473053efa94a0362fca162e17c174ca5ec1c8b..668418c0032d78718692876772bf0f042ee1355c 100644
--- a/bindings/pyroot_experimental/PyROOT/src/PyROOTPythonize.h
+++ b/bindings/pyroot_experimental/PyROOT/src/PyROOTPythonize.h
@@ -8,6 +8,9 @@ namespace PyROOT {
PyObject *AddPrettyPrintingPyz(PyObject *self, PyObject *args);
PyObject *PythonizeTTree(PyObject *self, PyObject *args);
+PyObject *GetEndianess(PyObject *self);
+PyObject *GetVectorDataPointer(PyObject *self, PyObject *args);
+PyObject *GetSizeOfType(PyObject *self, PyObject *args);
} // namespace PyROOT
diff --git a/bindings/pyroot_experimental/PyROOT/test/CMakeLists.txt b/bindings/pyroot_experimental/PyROOT/test/CMakeLists.txt
index 0a59db7d6596b8ced162bd8344466c58e671c6a7..9a3d8dac57649ce4f687a0f01e0dd0dd1ba8653a 100644
--- a/bindings/pyroot_experimental/PyROOT/test/CMakeLists.txt
+++ b/bindings/pyroot_experimental/PyROOT/test/CMakeLists.txt
@@ -1,5 +1,6 @@
# General pythonizations
ROOT_ADD_PYUNITTEST(pyroot_pretty_printing pretty_printing.py)
+ROOT_ADD_PYUNITTEST(pyroot_array_interface array_interface.py)
# TTree pythonizations
ROOT_ADD_PYUNITTEST(pyroot_pyz_ttree_branch_attr ttree_branch_attr.py
diff --git a/bindings/pyroot_experimental/PyROOT/test/array_interface.py b/bindings/pyroot_experimental/PyROOT/test/array_interface.py
new file mode 100644
index 0000000000000000000000000000000000000000..544682795feb08ac0b5694b79339324db104c9c2
--- /dev/null
+++ b/bindings/pyroot_experimental/PyROOT/test/array_interface.py
@@ -0,0 +1,50 @@
+import unittest
+import ROOT
+import numpy as np
+
+
+class ArrayInterface(unittest.TestCase):
+ # Helpers
+ dtypes = [
+ "int", "unsigned int", "long", "unsigned long", "float", "double"
+ ]
+
+ def get_maximum_for_dtype(self, dtype):
+ if np.issubdtype(dtype, np.integer):
+ return np.iinfo(dtype).max
+ if np.issubdtype(dtype, np.floating):
+ return np.finfo(dtype).max
+
+ def get_minimum_for_dtype(self, dtype):
+ if np.issubdtype(dtype, np.integer):
+ return np.iinfo(dtype).min
+ if np.issubdtype(dtype, np.floating):
+ return np.finfo(dtype).min
+
+ def check_memory_adoption(self, root_obj, np_obj):
+ root_obj[0] = self.get_maximum_for_dtype(np_obj.dtype)
+ root_obj[1] = self.get_minimum_for_dtype(np_obj.dtype)
+ self.assertEqual(root_obj[0], np_obj[0])
+ self.assertEqual(root_obj[1], np_obj[1])
+
+ def check_shape(self, expected_shape, np_obj):
+ self.assertEqual(expected_shape, np_obj.shape)
+
+ # Tests
+ def test_RVec(self):
+ for dtype in self.dtypes:
+ root_obj = ROOT.ROOT.VecOps.RVec(dtype)(2)
+ np_obj = np.asarray(root_obj)
+ self.check_memory_adoption(root_obj, np_obj)
+ self.check_shape((2, ), np_obj)
+
+ def test_STLVector(self):
+ for dtype in self.dtypes:
+ root_obj = ROOT.std.vector(dtype)(2)
+ np_obj = np.asarray(root_obj)
+ self.check_memory_adoption(root_obj, np_obj)
+ self.check_shape((2, ), np_obj)
+
+
+if __name__ == '__main__':
+ unittest.main()