Problem calling ROOT.TExec from a python script

ROOT
1

Dear rooters,

I have a problem with using TExec from a python script, which I use to setup custom color palettes.
A similar issue (also related with TExec) occured to me with the same script some time ago: see Multiple color palettes with python freezes program.

The following dummy script reproduces the problem:

#!/usr/bin/env python
import ROOT
import ctypes

ROOT.gROOT.SetBatch(1)
ROOT.gStyle.SetOptStat(0)

C = ROOT.TCanvas('C', 'C', 500, 500)
xmax = 5.
h1 = ROOT.TH2F('h1', '', 200, -xmax, xmax, 200, -xmax, xmax)
for i in range(0, 100000, 1):
    a, b = ctypes.c_double(), ctypes.c_double()
    ROOT.gRandom.Rannor(a, b)
    h1.Fill(a.value, b.value)

h1.Draw('col')
dt = ROOT.TDatime()
t = ROOT.TText(-0.9 * xmax, 0.9 * xmax, 't')
t.SetTextAlign(13)
t.SetTextSize(.05)
t.SetTextColor(4)
t.Draw()
ex = ROOT.TExec('ex', 'TPython::Exec("dt.Set()");TPython::Exec("t.SetTitle(dt.AsString())")')
ex.Draw()
ROOT.gPad.Update()
C.Print('./texec_problem.pdf')

Error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/delaossa/local/miniconda3/envs/root_base/lib/python3.8/site-packages/ROOT/__init__.py", line 22, in <module>
    import cppyy
  File "/Users/delaossa/local/miniconda3/envs/root_base/lib/python3.8/site-packages/cppyy/__init__.py", line 60, in <module>
    importlib.import_module(libcppyy_mod_name)
  File "/Users/delaossa/local/miniconda3/envs/root_base/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
SystemError: initialization of libcppyy3_8 did not return an extension module
Traceback (most recent call last):
  File "<string>", line 1, in <module>
NameError: name 'dt' is not defined
Traceback (most recent call last):
  File "<string>", line 1, in <module>
NameError: name 't' is not defined

My system is macOS BigSur 11.5.1 and I installed the root_base package with conda:

conda install -c conda-forge root_base=6.24.2=py38hc87488e_0

Python version:

Python 3.8.10 | packaged by conda-forge | (default, May 10 2021, 22:58:09)
[Clang 11.1.0 ] on darwin

The script works just fine on a Linux machine with the same root_base version and python 3.8.10.

Any ideas? Thank you very much!

2

Hello,

It could be a problem with the installation, according to this message:

SystemError: initialization of libcppyy3_8 did not return an extension module

What happens if you do import libcppyy3_8 directly from the Python prompt? Does it fail with the same error?

3

Hello,
import libcppyy3_8 goes fine (no warnings or anything):

Python 3.8.10 | packaged by conda-forge | (default, May 10 2021, 22:58:09)
[Clang 11.1.0 ] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import libcppyy3_8
>>>

However, import libcppyy says something else:

Python 3.8.10 | packaged by conda-forge | (default, May 10 2021, 22:58:09)
[Clang 11.1.0 ] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import cppyy
/Users/delaossa/local/miniconda3/envs/root_base/lib/python3.8/site-packages/cppyy_backend/loader.py:113: UserWarning: No precompiled header available (/Users/delaossa/local/miniconda3/envs/root_base/lib/python3.8/site-packages/cppyy_backend/etc not writable); this may impact performance.
  warnings.warn('No precompiled header available (%s); this may impact performance.' % msg)
>>>

Does it help to pin down the problem?
Thank you very much for looking into this!

4

Hello,

Looks like the libcppyy library is fine, no idea why it complains in the first case. The warning when importing cppyy is unrelated.

I tried the code above both with a conda ROOT installation (6.24.2, Py3.9) and master from source and I can’t reproduce.

Perhaps recreating the environment would help?

What happens if you do:

conda create -c conda-forge root_base=6.24.2 --name root_624
conda activate root_624

and try to run the code again?

5

Hello,
I get exactly the same error.

Python 3.9.6 | packaged by conda-forge | (default, Jul 11 2021, 03:36:15)
[Clang 11.1.0 ] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

root
   ------------------------------------------------------------------
  | Welcome to ROOT 6.24/02                        https://root.cern |
  | (c) 1995-2021, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for macosx64 on Jul 03 2021, 08:06:00                      |
  | From tag , 28 June 2021                                          |
  | With                                                             |
  | Try '.help', '.demo', '.license', '.credits', '.quit'/'.q'       |
   ------------------------------------------------------------------

and the error:

python texec_problem.py
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/delaossa/local/miniconda3/envs/root_624/lib/python3.9/site-packages/ROOT/__init__.py", line 22, in <module>
    import cppyy
  File "/Users/delaossa/local/miniconda3/envs/root_624/lib/python3.9/site-packages/cppyy/__init__.py", line 60, in <module>
    importlib.import_module(libcppyy_mod_name)
  File "/Users/delaossa/local/miniconda3/envs/root_624/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
SystemError: initialization of libcppyy3_9 did not return an extension module
Traceback (most recent call last):
  File "<string>", line 1, in <module>
NameError: name 'dt' is not defined
Traceback (most recent call last):
  File "<string>", line 1, in <module>
NameError: name 't' is not defined
(bool) false
Traceback (most recent call last):
  File "<string>", line 1, in <module>
NameError: name 'dt' is not defined
Traceback (most recent call last):
  File "<string>", line 1, in <module>
NameError: name 't' is not defined
(bool) false
Info in <TCanvas::Print>: pdf file ./texec_problem.pdf has been created

Did you try with a Mac too?
Could be a matter of the environment over which my conda is installed?
I have Command_Line_Tools_for_Xcode_12.5.1 and the latest Homebrew installed.
Cheers

6

No, I tried on Linux, I’ll try to reproduce on a Mac.

@chrisburr have you seen this before?

7

Could be a matter of the environment over which my conda is installed?

You could perhaps try cleaning that environment?

8

I can reproduce on Mac 11, this is enough to see the libcppyy error:

>>> import ROOT
>>> ROOT.TPython.Exec("")
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/sftnight/miniconda3/envs/root_624/lib/python3.9/site-packages/ROOT/__init__.py", line 22, in <module>
    import cppyy
  File "/Users/sftnight/miniconda3/envs/root_624/lib/python3.9/site-packages/cppyy/__init__.py", line 60, in <module>
    importlib.import_module(libcppyy_mod_name)
  File "/Users/sftnight/miniconda3/envs/root_624/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
SystemError: initialization of libcppyy3_9 did not return an extension module

So it’s an issue with TPython, still don’t know the reason though.

9

I can’t reproduce on the same machine with a ROOT installation built from source. It might be something related to the conda installation on MacOS then, @chrisburr any thoughts? The problem seems to happen during the initialization of TPython.

10

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