# Issue with running the model **URL:** \ **Category:** Support\ **Created:** [8 February 2022 13:14 UTC](https://brian.discourse.group/t/issue-with-running-the-model/604 "2022-02-08T13:14:01Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![dokato](https://avatars.discourse-cdn.com/v4/letter/d/f1d935/32.png) [@dokato](https://brian.discourse.group/u/dokato)\ **Post date:** [8 February 2022 13:14 UTC](https://brian.discourse.group/t/issue-with-running-the-model/604/1 "2022-02-08T13:14:01Z")
# Description of problem I’m getting the difficult to debug error when I try to run the code included below. The error message is not very informative. # Minimal code to reproduce problem ```auto tau_e=5 * ms # excitatory synaptic time constant tau_i=10 * ms # inhibitory synaptic time constant tau_Ia = 1000*ms # adaptation current tau_ref = 2 * ms, # refractory time SFA = 0.1 * nS, # conductance adaptation Vr=-60 * mV # resting potential VT=-35 * mV # spike threshold DeltaT=1 * mV g_l = 5 * nS # leak conductance E_l = -60 * mV E_e = 0 * mV # excitatory synaptic potential E_i = -75 * mV # inhibitory synaptic potential E_Ia = -90*mV C_m = 100 * pF # capacitance start_scope() eqs = ''' dv/dt = (g_l*(E_l-v) + g_e*(E_e-v) - g_i*(E_i-v) - g_Ia*(E_Ia-v))/C_m : volt (unless refractory) dg_e/dt = -g_e/tau_e : siemens dg_i/dt = -g_i/tau_i : siemens dg_Ia/dt = -g_Ia/tau_Ia : siemens ''' G = NeuronGroup(10, eqs, threshold='v > VT', reset='''v = Vr; g_Ia-=SFA''', refractory = tau_ref) G.v = -30 * mV M = StateMonitor(G, 'v', record=True) run(duration = 100*ms) plot(M.t/ms, M.v[0]) xlabel('Time (ms)') ylabel('v') ``` # What you have aready tried I tried to use `Equations`. # Full traceback of error (if relevant) ```auto File ~/anaconda3/envs/brian/lib/python3.10/re.py:240, in findall(pattern, string, flags) 233 """Return a list of all non-overlapping matches in the string. 234 235 If one or more capturing groups are present in the pattern, return (...) 238 239 Empty matches are included in the result.""" --> 240 return _compile(pattern, flags).findall(string) TypeError: expected string or bytes-like object The above exception was the direct cause of the following exception: BrianObjectException Traceback (most recent call last) Input In [69], in 33 G.v = -60 * mV 35 M = StateMonitor(G, 'v', record=True) ---> 37 run(duration = 100*ms) 39 plot(M.t/ms, M.v[0]) 40 xlabel('Time (ms)') File ~/anaconda3/envs/brian/lib/python3.10/site-packages/brian2/units/fundamentalunits.py:2428, in check_units..do_check_units..new_f(*args, **kwds) 2421 error_message = (f"Function '{f. __name__ }' " 2422 f"expected a quantitity with unit " 2423 f"{unit} for argument '{k}' but got " 2424 f"'{value}'") 2425 raise DimensionMismatchError(error_message, 2426 get_dimensions(newkeyset[k])) -> 2428 result = f(*args, **kwds) 2429 if 'result' in au: 2430 if isinstance(au['result'], Callable) and au['result'] != bool: File ~/anaconda3/envs/brian/lib/python3.10/site-packages/brian2/core/magic.py:373, in run(duration, report, report_period, namespace, profile, level) 310 @check_units(duration=second, report_period=second) 311 def run(duration, report=None, report_period=10*second, namespace=None, 312 profile=None, level=0): 313 """ 314 run(duration, report=None, report_period=10*second, namespace=None, level=0) 315 (...) 371 intended use. See `MagicNetwork` for more details. 372 """ --> 373 return magic_network.run(duration, report=report, report_period=report_period, 374 namespace=namespace, profile=profile, level=2+level) File ~/anaconda3/envs/brian/lib/python3.10/site-packages/brian2/core/magic.py:230, in MagicNetwork.run(self, duration, report, report_period, namespace, profile, level) 227 def run(self, duration, report=None, report_period=10*second, 228 namespace=None, profile=None, level=0): 229 self._update_magic_objects(level=level+1) --> 230 Network.run(self, duration, report=report, report_period=report_period, 231 namespace=namespace, profile=profile, level=level+1) File ~/anaconda3/envs/brian/lib/python3.10/site-packages/brian2/core/base.py:293, in device_override..device_override_decorator..device_override_decorated_function(*args, **kwds) 291 return getattr(curdev, name)(*args, **kwds) 292 else: --> 293 return func(*args, **kwds) File ~/anaconda3/envs/brian/lib/python3.10/site-packages/brian2/units/fundamentalunits.py:2428, in check_units..do_check_units..new_f(*args, **kwds) 2421 error_message = (f"Function '{f. __name__ }' " 2422 f"expected a quantitity with unit " 2423 f"{unit} for argument '{k}' but got " 2424 f"'{value}'") 2425 raise DimensionMismatchError(error_message, 2426 get_dimensions(newkeyset[k])) -> 2428 result = f(*args, **kwds) 2429 if 'result' in au: 2430 if isinstance(au['result'], Callable) and au['result'] != bool: File ~/anaconda3/envs/brian/lib/python3.10/site-packages/brian2/core/network.py:1006, in Network.run(self, duration, report, report_period, namespace, profile, level) 1003 if namespace is None: 1004 namespace = get_local_namespace(level=level+3) -> 1006 self.before_run(namespace) 1008 if len(all_objects) == 0: 1009 return # TODO: raise an error? warning? File ~/anaconda3/envs/brian/lib/python3.10/site-packages/brian2/core/base.py:293, in device_override..device_override_decorator..device_override_decorated_function(*args, **kwds) 291 return getattr(curdev, name)(*args, **kwds) 292 else: --> 293 return func(*args, **kwds) File ~/anaconda3/envs/brian/lib/python3.10/site-packages/brian2/core/network.py:894, in Network.before_run(self, run_namespace) 892 obj.before_run(run_namespace) 893 except Exception as ex: --> 894 raise BrianObjectException("An error occurred when preparing an object.", obj) from ex 896 # Check that no object has been run as part of another network before 897 for obj in all_objects: BrianObjectException: Error encountered with object named 'neurongroup_17_stateupdater'. Object was created here (most recent call only, full details in debug log): File '/var/folders/zt/s4rb4_kj4pnbmcqw7xyw52hw0000gn/T/ipykernel_88701/1728005146.py', line 28, in G = NeuronGroup(10, ``` Clearly I made a mistake somewhere, not sure where? ---
**Author:** ![mstimberg](https://yyz2.discourse-cdn.com/free1/user_avatar/brian.discourse.group/mstimberg/32/11_2.png) [@mstimberg](https://brian.discourse.group/u/mstimberg)\ **Post date:** [8 February 2022 13:33 UTC](https://brian.discourse.group/t/issue-with-running-the-model/604/2 "2022-02-08T13:33:31Z")
Hi. This error message is indeed not very helpful… The problem is the definition of `tau_ref` (and `SFA` which would have raised an error later): > [@dokato](#): > > ```auto > tau_ref = 2 * ms, # refractory time > SFA = 0.1 * nS, # conductance adaptation > > ``` Both variables have a comma on the right-hand side, the variable `tau_ref` is therefore a tuple `(2*ms, )` instead of a `Quantity`. For the refractory period, Brian tries to treat everything that is not a `Quantity` as a string expression, which leads to the error message. ---
**Author:** ![dokato](https://avatars.discourse-cdn.com/v4/letter/d/f1d935/32.png) [@dokato](https://brian.discourse.group/u/dokato)\ **Post date:** [8 February 2022 14:25 UTC](https://brian.discourse.group/t/issue-with-running-the-model/604/3 "2022-02-08T14:25:49Z")
Oh, of course, thank you @mstimberg . Too much c&p, too little coffee today 😉