PySpice duplicate declaration error in multithread parallel setting

[YuxinPan]

Environment (OS, Python version, PySpice version, simulator)

Ubuntu 20.04, Python 3.9.7, PySpice 1.5

Expected Behaviour

Work with Python Thread for parallel circuit simulation

Actual Behaviour

Exception in thread Thread-9:
Traceback (most recent call last):
  File "/home/kyle/anaconda3/lib/python3.9/threading.py", line 973, in _bootstrap_inner
    self.run()
  File "/home/kyle/anaconda3/lib/python3.9/threading.py", line 910, in run
    self._target(*self._args, **self._kwargs)
  File "/tmp/ipykernel_621643/3113114828.py", line 15, in sim_thread
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/PySpice/Spice/Netlist.py", line 1292, in simulator
    return CircuitSimulator.factory(self, *args, **kwargs)
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/PySpice/Spice/Simulation.py", line 1167, in factory
    return sub_cls(circuit, *args, **kwargs)
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/PySpice/Spice/NgSpice/Simulation.py", line 99, in __init__
    self._ngspice_shared = NgSpiceShared.new_instance()
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/PySpice/Spice/NgSpice/Shared.py", line 449, in new_instance
    instance = cls(ngspice_id=ngspice_id, send_data=send_data, verbose=verbose)
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/PySpice/Spice/NgSpice/Shared.py", line 479, in __init__
    self._load_library(verbose)
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/PySpice/Spice/NgSpice/Shared.py", line 533, in _load_library
    ffi.cdef(fh.read())
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/cffi/api.py", line 112, in cdef
    self._cdef(csource, override=override, packed=packed, pack=pack)
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/cffi/api.py", line 126, in _cdef
    self._parser.parse(csource, override=override, **options)
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/cffi/cparser.py", line 389, in parse
    self._internal_parse(csource)
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/cffi/cparser.py", line 428, in _internal_parse
    realtype, quals = self._get_type_and_quals(
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/cffi/cparser.py", line 674, in _get_type_and_quals
    tp = self._get_struct_union_enum_type('struct', type, name)
  File "/home/kyle/anaconda3/lib/python3.9/site-packages/cffi/cparser.py", line 821, in _get_struct_union_enum_type
    raise CDefError("duplicate declaration of struct %s" % name)
cffi.CDefError: <cdef source string>:7: duplicate declaration of struct ngcomplex

Steps to reproduce the behaviour

The minimally required code to reproduce this error is attached below:

from threading import Thread
from PySpice.Spice.Netlist import Circuit
from PySpice.Unit import *

def sim_thread(index):
    circuit = Circuit('Resistor Bridge')

    circuit.V('input', 1, circuit.gnd, 10@u_V)
    circuit.R(1, 1, 2, 2@u_kΩ)
    circuit.R(2, 1, 3, 1@u_kΩ)
    circuit.R(3, 2, circuit.gnd, 1@u_kΩ)
    circuit.R(4, 3, circuit.gnd, 2@u_kΩ)
    circuit.R(5, 3, 2, 2@u_kΩ)

    simulator = circuit.simulator(temperature=25, nominal_temperature=25)
    analysis = simulator.operating_point()
    
threads = [None] * 2
    
for i in range(len(threads)):
    threads[i] = Thread(target=sim_thread, args=(i,))
    threads[i].start()
    
for i in range(len(threads)):
    threads[i].join()

Note that the above code works when only 1 thread is called, indicating that the setup and environment are functioning (not an issue with single thread code).

[YuxinPan]

Hi @FabriceSalvaire !

I am wondering if you are aware of any successful implementation of PySpice simulation in multi-thread envorinment?

Thanks a lot.