Example #1
0
    def __init__(self,
                 morphology=None,
                 model=None,
                 threshold=None,
                 reset=NoReset(),
                 refractory=0 * ms,
                 level=0,
                 clock=None,
                 unit_checking=True,
                 compile=False,
                 freeze=False,
                 implicit=True,
                 Cm=0.9 * uF / cm**2,
                 Ri=150 * ohm * cm,
                 bc_type=2,
                 diffeq_nonzero=True):
        clock = guess_clock(clock)
        N = len(morphology)  # number of compartments

        if isinstance(model, str):
            model = Equations(model, level=level + 1)

        model += Equations('''
		v:volt # membrane potential
		''')

        # Process model equations (Im) to extract total conductance and the remaining current
        if use_sympy:
            try:
                membrane_eq = model._string['Im']  # the membrane equation
            except:
                raise TypeError, "The transmembrane current Im must be defined"
            # Check conditional linearity
            ids = get_identifiers(membrane_eq)
            _namespace = dict.fromkeys(
                ids, 1.
            )  # there is a possibility of problems here (division by zero)
            _namespace['v'] = AffineFunction()
            eval(membrane_eq, model._namespace['v'], _namespace)
            try:
                eval(membrane_eq, model._namespace['v'], _namespace)
            except:  # not linear
                raise TypeError, "The membrane current must be linear with respect to v"
            # Extracts the total conductance from Im, and the remaining current
            z = symbolic_eval(membrane_eq)
            symbol_v = sympy.Symbol('v')
            b = z.subs(symbol_v, 0)
            a = -sympy.simplify(z.subs(symbol_v, 1) - b)
            gtot_str = "_gtot=" + str(a) + ": siemens/cm**2"
            I0_str = "_I0=" + str(b) + ": amp/cm**2"
            model += Equations(
                gtot_str + "\n" + I0_str, level=level +
                1)  # better: explicit insertion with namespace of v
        else:
            raise TypeError, "The Sympy package must be installed for SpatialNeuron"

        # Equations for morphology (isn't it a duplicate??)
        eqs_morphology = Equations("""
		diameter : um
		length : um
		x : um
		y : um
		z : um
		area : um**2
		""")

        full_model = model + eqs_morphology

        NeuronGroup.__init__(self,
                             N,
                             model=full_model,
                             threshold=threshold,
                             reset=reset,
                             refractory=refractory,
                             level=level + 1,
                             clock=clock,
                             unit_checking=unit_checking,
                             implicit=implicit)
        self.model_with_diffeq_nonzero = diffeq_nonzero
        self._state_updater = SpatialStateUpdater(self, clock)
        self.Cm = ones(len(self)) * Cm
        self.Ri = Ri
        self.bc_type = bc_type  #default boundary condition on leaves
        self.bc = ones(len(self))  # boundary conditions on branch points
        self.changed = True

        # Insert morphology
        self.morphology = morphology
        self.morphology.compress(diameter=self.diameter,
                                 length=self.length,
                                 x=self.x,
                                 y=self.y,
                                 z=self.z,
                                 area=self.area)
Example #2
0
    def __init__(self,
                 morphology=None,
                 model=None,
                 threshold=None,
                 reset=NoReset(),
                 refractory=0 * ms,
                 level=0,
                 clock=None,
                 unit_checking=True,
                 compile=False,
                 freeze=False,
                 Cm=0.9 * uF / cm**2,
                 Ri=150 * ohm * cm):
        clock = guess_clock(clock)
        N = len(morphology)  # number of compartments

        if isinstance(model, str):
            model = Equations(model, level=level + 1)

        model += Equations('''
        v:volt # membrane potential
        ''')

        # Process model equations (Im) to extract total conductance and the remaining current
        if use_sympy:
            try:
                membrane_eq = model._string['Im']  # the membrane equation
            except:
                raise TypeError, "The transmembrane current Im must be defined"
            # Check conditional linearity
            ids = get_identifiers(membrane_eq)
            _namespace = dict.fromkeys(
                ids, 1.
            )  # there is a possibility of problems here (division by zero)
            _namespace['v'] = AffineFunction()
            eval(membrane_eq, model._namespace['v'], _namespace)
            try:
                eval(membrane_eq, model._namespace['v'], _namespace)
            except:  # not linear
                raise TypeError, "The membrane current must be linear with respect to v"
            # Extracts the total conductance from Im, and the remaining current
            z = symbolic_eval(membrane_eq)
            symbol_v = sympy.Symbol('v')
            b = z.subs(symbol_v, 0)
            a = -sympy.simplify(z.subs(symbol_v, 1) - b)
            gtot_str = "_gtot=" + str(a) + ": siemens/cm**2"
            I0_str = "_I0=" + str(b) + ": amp/cm**2"
            model += Equations(
                gtot_str + "\n" + I0_str, level=level +
                1)  # better: explicit insertion with namespace of v
        else:
            raise TypeError, "The Sympy package must be installed for SpatialNeuron"

        # Equations for morphology (isn't it a duplicate??)
        eqs_morphology = Equations("""
        diameter : um
        length : um
        x : um
        y : um
        z : um
        area : um**2
        """)

        full_model = model + eqs_morphology

        # Create the state updater
        NeuronGroup.__init__(self,
                             N,
                             model=full_model,
                             threshold=threshold,
                             reset=reset,
                             refractory=refractory,
                             level=level + 1,
                             clock=clock,
                             unit_checking=unit_checking,
                             implicit=True)

        #Group.__init__(self, full_model, N, unit_checking=unit_checking, level=level+1)
        #self._eqs = model
        #var_names = full_model._diffeq_names
        self.Cm = Cm  # could be a vector?
        self.Ri = Ri
        self._state_updater = SpatialStateUpdater(self, clock)
        #S0 = {}
        # Fill missing units
        #for key, value in full_model._units.iteritems():
        #    if not key in S0:
        #        S0[key] = 0 * value
        #self._S0 = [0] * len(var_names)
        #for var, i in zip(var_names, count()):
        #    self._S0[i] = S0[var]

        # Insert morphology
        self.morphology = morphology
        self.morphology.compress(diameter=self.diameter,
                                 length=self.length,
                                 x=self.x,
                                 y=self.y,
                                 z=self.z,
                                 area=self.area)