Error when using scv.tl.velocity_graph

[KforKuma]

Quite similar to https://github.com/theislab/scvelo/issues/954 Interestingly in all 4 times I tried, it worked once but failed other times. I still don't know why.

my anndata object is very small so I guess using pancreas could produce same result, I'm gonna try it later (since my server is currently with internet problem)

update: after waiting for two hours with pancreas dataset, this line didn't return anything. so i guess it's not very reproducible, let me test it further.

scv.tl.velocity_graph(matching_velo)

Error output

```pytb computing velocity graph (using 1/24 cores) 0%| | 0/8389 [00:00", line 1, in File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/site-packages/scvelo/tools/velocity_graph.py", line 373, in velocity_graph vgraph.compute_cosines(n_jobs=n_jobs, backend=backend) File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/site-packages/scvelo/tools/velocity_graph.py", line 185, in compute_cosines res = parallelize( File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/site-packages/scvelo/core/_parallelize.py", line 121, in wrapper queue = Manager().Queue() File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/multiprocessing/managers.py", line 723, in temp token, exp = self._create(typeid, *args, **kwds) File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/multiprocessing/managers.py", line 606, in _create conn = self._Client(self._address, authkey=self._authkey) File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/multiprocessing/connection.py", line 513, in Client answer_challenge(c, authkey) File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/multiprocessing/connection.py", line 757, in answer_challenge message = connection.recv_bytes(256) # reject large message File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/multiprocessing/connection.py", line 221, in recv_bytes buf = self._recv_bytes(maxlength) File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/multiprocessing/connection.py", line 419, in _recv_bytes buf = self._recv(4) File "/data/HeLab/miniconda3/envs/scvpy10/lib/python3.10/multiprocessing/connection.py", line 388, in _recv raise EOFError EOFError ```

Versions

```pytb scvelo==0.3.1 scanpy==1.9.6 anndata==0.10.3 loompy==3.0.7 numpy==1.26.2 scipy==1.11.4 matplotlib==3.7.0 sklearn==1.1.3 pandas==2.1.4 ```

[WeilerP]

Looks like a local issue with multithreading to me and similar to #746 as described in #954.