Hi,
In my code I had the following part:
self.pcd = np.zeros((X, Y, A, B), dtype=np.uint8)
self.tree_chain.SetBranchAddress("photon_count_data", self.pcd)
where photon_count_data is photon_count_data[1][1][48][48]/b
It used to work in older ROOT versions (6.30 I think), but now I get an error:
File "/home/lewhoo/workspace/etos/eusottrees/datatree.py", line 1652, in set_physical_tree
self.tree_chain.SetBranchAddress("photon_count_data", self.pcd)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/lewhoo/software/root/root-6.38.00/lib/ROOT/_pythonization/_ttree.py", line 266, in _SetBranchAddress
data_type = _determine_data_type(addr)
File "/home/lewhoo/software/root/root-6.38.00/lib/ROOT/_pythonization/_ttree.py", line 233, in _determine_data_type
return _get_cpp_type_from_numpy_type(addr.__array_interface__["typestr"][1:])
File "/home/lewhoo/software/root/root-6.38.00/lib/ROOT/_pythonization/_rvec.py", line 149, in _get_cpp_type_from_numpy_type
raise RuntimeError("Object not convertible: Python object has unknown data-type '" + dtype + "'.")
RuntimeError: Object not convertible: Python object has unknown data-type 'u1'.
The workaround (suggested by Gemini 
) is to use GetBranch(“…”).SetAddress(…) and this works. However, it seems that proper conversion from numpy array uint8 to C++ unsigned char is missing.
ROOT Version: 6.38
Platform: Fedora 43