Source code for brian2.equations.refractory

Module implementing Brian's refractory mechanism.

from brian2.units.fundamentalunits import Unit, DIMENSIONLESS
from brian2.units.allunits import second

from .equations import (Equations, SingleEquation, DIFFERENTIAL_EQUATION,
                        PARAMETER, Expression, BOOLEAN)

__all__ = ['add_refractoriness']

[docs]def check_identifier_refractory(identifier): ''' Check that the identifier is not using a name reserved for the refractory mechanism. The reserved names are `not_refractory`, `refractory`, `refractory_until`. Parameters ---------- identifier : str The identifier to check. Raises ------ ValueError If the identifier is a variable name used for the refractory mechanism. ''' if identifier in ('not_refractory', 'refractory', 'refractory_until'): raise SyntaxError('The name "%s" is used in the refractory mechanism ' ' and should not be used as a variable ' 'name.' % identifier)
[docs]def add_refractoriness(eqs): ''' Extends a given set of equations with the refractory mechanism. New parameters are added and differential equations with the "unless refractory" flag are changed so that their right-hand side is 0 when the neuron is refractory (by multiplication with the ``not_refractory`` variable). Parameters ---------- eqs : `Equations` The equations without refractory mechanism. Returns ------- new_eqs : `Equations` New equations, with added parameters and changed differential equations having the "unless refractory" flag. ''' new_equations = [] # replace differential equations having the active flag for eq in eqs.values(): if eq.type == DIFFERENTIAL_EQUATION and 'unless refractory' in eq.flags: # the only case where we have to change anything new_code = 'int(not_refractory)*(' + eq.expr.code + ')' new_equations.append(SingleEquation(DIFFERENTIAL_EQUATION, eq.varname, eq.dim, expr=Expression(new_code), flags=eq.flags)) else: new_equations.append(eq) # add new parameters new_equations.append(SingleEquation(PARAMETER, 'not_refractory', DIMENSIONLESS, var_type=BOOLEAN)) new_equations.append(SingleEquation(PARAMETER, 'lastspike', second.dim)) return Equations(new_equations)