human
I am working on the file "2019_RDM_course_nix.ipynb".
The first task is:
Referencing a single point or region in a DataArray
To reference only a single point or region, we can use a NIX tag. The NIX tag is a simpler form of the MultiTag that we will cover in a moment.
Can you write Python code for it?
 Give me a the Python code you requested?
assistant
#Here is the Python code you requested.

# We will create some more elaborate example data to make a point
# For this we need some equally elaborate code, which can be safely ignored.

# This code will create some mock membrane voltage traces for us

# ---- MOCK CODE AND DATA; the code can be safely ignored --------

class LIF(object):
    def __init__(self, stepsize=0.0001, offset=1.6, tau_m=0.025, tau_a=0.02, da=0.0, D=3.5):
        self.stepsize = stepsize  # simulation stepsize [s]
        self.offset = offset  # offset curent [nA]
        self.tau_m = tau_m  # membrane time_constant [s]
        self.tau_a = tau_a  # adaptation time_constant [s]
        self.da = da  # increment in adaptation current [nA]
        self.D = D  # noise intensity
        self.v_threshold = 1.0  # spiking threshold
        self.v_reset = 0.0  # reset voltage after spiking
        self.i_a = 0.0  # current adaptation current
        self.v = self.v_reset  # current membrane voltage
        self.t = 0.0  # current time [s]
        self.membrane_voltage = []
        self.spike_times = []

    def _reset(self):
        self.i_a = 0.0
        self.v = self.v_reset
        self.t = 0.0
        self.membrane_voltage = []
        self.spike_times = []

    def _lif(self, stimulus, noise):
        """
        euler solution of the membrane equation with adaptation current and noise
        """
        self.i_a -= self.i_a - self.stepsize/self.tau_a * (self.i_a)
        self.v += self.stepsize * ( -self.v + stimulus + noise + self.offset - self.i_a)/self.tau_m;
        self.membrane_voltage.append(self.v)

    def _next(self, stimulus):
        """
        working horse which delegates to the euler and gets the spike times
        """
        noise = self.D * (float(np.random.randn() % 10000) - 5000.0)/10000
        self._lif(stimulus, noise)
        self.t += self.stepsize
        if self.v > self.v_threshold and len(self.membrane_voltage) > 1:
            self.v = self.v_reset
            self.membrane_voltage[len(self.membrane_voltage)-1] = 2.0
           ...