OSError: cannot load library 'libngspice.so'

[tamenol]

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

Linux Ubuntu 16.04
Python 3.5
PySpice 1.1.4

Expected Behaviour

Running

import PySpice.Logging.Logging as Logging
logger = Logging.setup_logging()

from PySpice.Spice.NgSpice.Shared import NgSpiceShared

ngspice = NgSpiceShared.new_instance()

print(ngspice.exec_command('version -f'))
print(ngspice.exec_command('print all'))
print(ngspice.exec_command('devhelp resistor'))

without erros.

Actual Behaviour

(venv) speklap:thesis_pcb$ python -i run.py

2018-06-01 15:02:01,206 - PySpice.Spice.NgSpice.Shared.NgSpiceShared.new_instance - INFO - New instance for id 0
Traceback (most recent call last):
File "run.py", line 6, in
ngspice = NgSpiceShared.new_instance()
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/PySpice/Spice/NgSpice/Shared.py", line 338, in new_instance
instance = cls(ngspice_id=ngspice_id, send_data=send_data)
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/PySpice/Spice/NgSpice/Shared.py", line 356, in init
self._load_library()
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/PySpice/Spice/NgSpice/Shared.py", line 381, in _load_library
self._ngspice_shared = ffi.dlopen(library_path)
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/cffi/api.py", line 141, in dlopen
lib, function_cache = _make_ffi_library(self, name, flags)
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/cffi/api.py", line 802, in _make_ffi_library
backendlib = _load_backend_lib(backend, libname, flags)
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/cffi/api.py", line 797, in _load_backend_lib
raise OSError(msg)
OSError: cannot load library 'libngspice.so': libngspice.so: cannot open shared object file: No such file or directory. Additionally, ctypes.util.find_library() did not manage to locate a library called 'libngspice.so'

Steps to reproduce the behaviour

I've install pyspice using pip in a virtual environment. ngspice I tried installing through apt-get and through tarball. I can open the ngspice 'console' and use it to simulate but can't use it with python.

I can't locate libngspice.so on my system, also my $LD_LIBRARY_PATH shows up empty.

How can I fix this? Thanks

[FabriceSalvaire]

can you confirm on version 1.2 ?

[tamenol]

I've reinstalled it using
$ pip install git+https://github.com/FabriceSalvaire/PySpice

2018-06-07 18:10:33,939 - PySpice.Spice.NgSpice.Shared.NgSpiceShared.new_instance - INFO - New instance for id 0
2018-06-07 18:10:33,967 - PySpice.Spice.NgSpice.Shared.NgSpiceShared._load_library - DEBUG - Load libngspice.so
Traceback (most recent call last):
File "run.py", line 6, in
ngspice = NgSpiceShared.new_instance()
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/PySpice/Spice/NgSpice/Shared.py", line 331, in new_instance
instance = cls(ngspice_id=ngspice_id, send_data=send_data)
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/PySpice/Spice/NgSpice/Shared.py", line 349, in init
self._load_library()
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/PySpice/Spice/NgSpice/Shared.py", line 375, in _load_library
self._ngspice_shared = ffi.dlopen(library_path)
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/cffi/api.py", line 141, in dlopen
lib, function_cache = _make_ffi_library(self, name, flags)
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/cffi/api.py", line 802, in _make_ffi_library
backendlib = _load_backend_lib(backend, libname, flags)
File "/home/speklap/Projects/InProgress/thesis_pcb/venv/lib/python3.5/site-packages/cffi/api.py", line 797, in _load_backend_lib
raise OSError(msg)
OSError: cannot load library 'libngspice.so': libngspice.so: cannot open shared object file: No such file or directory. Additionally, ctypes.util.find_library() did not manage to locate a library called 'libngs
pice.so'

$LD_LIBRARY_PATH is still empty. Do I need to insert some path to $LD_LIBRARY_PATH?

[FabriceSalvaire]

what is the path of libngspice.so on your env ?

[tamenol]

I had installed ngspice using apt-get. I couldn't find the library myself as well. I purged it and tried installing through git with the correct configure option to create the shared library. I haven't got it installed properly yet this way. Something is still broken on my system it seems. Will report back once I got ngspice working.

[FabriceSalvaire]

You have to check the shared library is provided in the package, some linux distributions don't include it.

[peteut]

Hitting the same error, using Debian buster. The filename is libngspice.so.0 in this case.

$ sudo ldconfig -p | grep libngspice.so
        libngspice.so.0 (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libngspice.so.0

[peteut]

ctyles.util.find_library should probably be used here:

from ctypes.util import find_library

ngspice_lib_filename = find_library('ngspice')

[oe1rsa]

sudo apt-get libngspice0-dev

[tadeussilver]

I have a similar error when trying to simulate this example
https://pyspice.fabrice-salvaire.fr/examples/filter/low-pass-rc-filter.html
I get the following error
`2020-05-25 00:55:20,166 - PySpice.Spice.NgSpice.Shared.NgSpiceShared.new_instance - INFO - New instance for id 0
2020-05-25 00:55:20,166 - PySpice.Spice.NgSpice.Shared.NgSpiceShared._load_library - WARNING - Set locale LC_NUMERIC to C

---

OSError Traceback (most recent call last)

in ()
----> 1 simulator = circuit.simulator(temperature=25, nominal_temperature=25)
2 analysis = simulator.ac(start_frequency=1@u_Hz, stop_frequency=1@u_MHz, number_of_points=10, variation='dec')

8 frames

/usr/local/lib/python3.6/dist-packages/cffi/api.py in _load_backend_lib(backend, name, flags)
825 if first_error is not None:
826 msg = "%s. Additionally, %s" % (first_error, msg)
--> 827 raise OSError(msg)
828 return backend.load_library(path, flags)
829

OSError: cannot load library 'libngspice.so': libngspice.so: cannot open shared object file: No such file or directory. Additionally, ctypes.util.find_library() did not manage to locate a library called 'libngspice.so'

when trying to install libngspice0 library I get another errorProcessing triggers for libc-bin (2.27-3ubuntu1) ...
/sbin/ldconfig.real: /usr/local/lib/python3.6/dist-packages/ideep4py/lib/libmkldnn.so.0 is not a symbolic link

Errors were encountered while processing:
libngspice0:amd64`
I have already tried many things, almost none of them works, I am not very good at programming, among other things, I really need the module to work in the circuit simulation because I do not have multisim due to the economic resources, therefore if anyone has any solution I am grateful.

my system details are as follows
ubuntu 18.04, python 3.6.2, pyspice 1.4.2

[tamenol]

Yeah I'm sorry. This is too long ago for me and I don't know anymore what I did.

[tadeussilver]

help, I already investigated a lot without result, do you know a better alternative than pyscpice?