contraction_compressed method

[maxtremblay]

Hello, I accidentally found the TensorNetwork.contract_compressed method and I tried to use it. However, I get this weird error message regarding Numba

File "/home/maxime/Documents/procus/examples/decoding.py", line 105, in <module>
    solution = decoder.optimize(noise)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/procus/optimizer.py", line 89, in optimize
    distribution = self._update_solution_distribution(network, distribution)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/procus/optimizer.py", line 99, in _update_solution_distribution
    contraction = self.contraction.contract(
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/procus/optimizer.py", line 68, in contract
    return network.contract_compressed(
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/quimb/tensor/tensor_core.py", line 5407, in contract_compressed
    return tn._contract_compressed_tid_sequence(
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/quimb/tensor/tensor_core.py", line 5267, in _contract_compressed_tid_sequence
    _compress_neighbors(tid_new, t_new, d)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/quimb/tensor/tensor_core.py", line 5215, in _compress_neighbors
    self._compress_between_tids(
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/quimb/tensor/tensor_core.py", line 4197, in _compress_between_tids
    tensor_compress_bond(ta, tb, **compress_opts)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/quimb/tensor/tensor_core.py", line 922, in tensor_compress_bond
    T1_L, T1_R = T1.split(left_inds=left_env_ix, right_inds=shared_ix,
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/quimb/tensor/tensor_core.py", line 2098, in split
    return tensor_split(self, *args, **kwargs)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/quimb/tensor/tensor_core.py", line 792, in tensor_split
    left, s, right = split_fn(array, **opts)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/quimb/tensor/decomp.py", line 435, in qr
    return _qr_numba(x)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/dispatcher.py", line 439, in _compile_for_args
    raise e
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/dispatcher.py", line 372, in _compile_for_args
    return_val = self.compile(tuple(argtypes))
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/dispatcher.py", line 909, in compile
    cres = self._compiler.compile(args, return_type)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/dispatcher.py", line 79, in compile
    status, retval = self._compile_cached(args, return_type)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/dispatcher.py", line 93, in _compile_cached
    retval = self._compile_core(args, return_type)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/dispatcher.py", line 106, in _compile_core
    cres = compiler.compile_extra(self.targetdescr.typing_context,
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/compiler.py", line 604, in compile_extra
    pipeline = pipeline_class(typingctx, targetctx, library,
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/compiler.py", line 308, in __init__
    config.reload_config()
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/config.py", line 414, in reload_config
    _env_reloader.update()
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/config.py", line 107, in update
    self.process_environ(new_environ)
  File "/home/maxime/.miniconda/envs/procus-env/lib/python3.9/site-packages/numba/core/config.py", line 353, in process_environ
    raise RuntimeError("Cannot set NUMBA_NUM_THREADS to a "
RuntimeError: Cannot set NUMBA_NUM_THREADS to a different value once the threads have been launched (currently have 4, trying to set 8)

I tried to fix the number of threads using numba.set_num_threads(8) unsuccessfully. I don't know if this is more a numba issue or a quimb issue.

Also, should I consider this method production-ready? I am asking since it is not documented.

[jcmgray]

Hi @maxtremblay.

Firstly, no - this is very much not production or supported in any way yet! its some experimental infrastructure but several other things are needed to use it accurately and it will undergo lots of changes / improvements.

Regarding the bug however, this seems unrelated to contract_compressed. I suppose NUMBA_NUM_THREADS is being set somewhere else but not via an environment variable, meaning quimb needs some way of finding that out before exporting the env var itself. Do you know which/if any other packages you are importing also interact with numba?