# -*- coding: utf-8 -*-
#
# hh_psc_alpha.py
#
# This file is part of NEST.
#
# Copyright (C) 2004 The NEST Initiative
#
# NEST is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# NEST is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with NEST.  If not, see <http://www.gnu.org/licenses/>.

"""
Example using Hodgkin-Huxley neuron
-----------------------------------

This example produces a rate-response (FI) curve of the Hodgkin-Huxley
neuron ``hh_psc_alpha`` in response to a range of different current (DC) stimulations.
The result is plotted using matplotlib.

Since a DC input affects only the neuron's channel dynamics, this routine
does not yet check correctness of synaptic response.
"""

import matplotlib.pyplot as plt
import nest
import numpy as np

nest.set_verbosity("M_WARNING")
nest.ResetKernel()

simtime = 1000

# Amplitude range, in pA
dcfrom = 0
dcstep = 20
dcto = 2000

h = 0.1  # simulation step size in mS

neuron = nest.Create("hh_psc_alpha")
sr = nest.Create("spike_recorder")

sr.record_to = "memory"

nest.Connect(neuron, sr, syn_spec={"weight": 1.0, "delay": h})

# Simulation loop
n_data = int(dcto / float(dcstep))
amplitudes = np.zeros(n_data)
event_freqs = np.zeros(n_data)
for i, amp in enumerate(range(dcfrom, dcto, dcstep)):
    neuron.I_e = float(amp)
    print(f"Simulating with current I={amp} pA")
    nest.Simulate(1000)  # one second warm-up time for equilibrium state
    sr.n_events = 0  # then reset spike counts
    nest.Simulate(simtime)  # another simulation call to record firing rate

    n_events = sr.n_events
    amplitudes[i] = amp
    event_freqs[i] = n_events / (simtime / 1000.0)

plt.plot(amplitudes, event_freqs)
plt.show()