# Size of variable arrays: sizeAlgebraic = 11 sizeStates = 3 sizeConstants = 21 from math import * from numpy import * def createLegends(): legend_states = [""] * sizeStates legend_rates = [""] * sizeStates legend_algebraic = [""] * sizeAlgebraic legend_voi = "" legend_constants = [""] * sizeConstants legend_voi = "time in component environment (millisecond)" legend_states[0] = "V in component membrane (millivolt)" legend_constants[0] = "C in component membrane (nanoF)" legend_constants[1] = "i_app in component membrane (nanoA)" legend_algebraic[10] = "i_tonic_e in component tonic_current (nanoA)" legend_algebraic[3] = "i_Na in component fast_sodium_current (nanoA)" legend_algebraic[8] = "i_NaP in component persistent_sodium_current (nanoA)" legend_algebraic[6] = "i_K in component potassium_current (nanoA)" legend_algebraic[9] = "i_leak in component leakage_current (nanoA)" legend_constants[2] = "E_Na in component fast_sodium_current (millivolt)" legend_constants[3] = "g_Na in component fast_sodium_current (nanoS)" legend_algebraic[0] = "m_infinity in component fast_sodium_current_m_gate (dimensionless)" legend_states[1] = "n in component potassium_current_n_gate (dimensionless)" legend_constants[4] = "theta_m in component fast_sodium_current_m_gate (millivolt)" legend_constants[5] = "omega_m in component fast_sodium_current_m_gate (millivolt)" legend_constants[6] = "g_K in component potassium_current (nanoS)" legend_constants[7] = "E_K in component potassium_current (millivolt)" legend_algebraic[1] = "n_infinity in component potassium_current_n_gate (dimensionless)" legend_algebraic[4] = "tau_n in component potassium_current_n_gate (millisecond)" legend_constants[8] = "tau_n_max in component potassium_current_n_gate (millisecond)" legend_constants[9] = "theta_n in component potassium_current_n_gate (millivolt)" legend_constants[10] = "omega_n in component potassium_current_n_gate (millivolt)" legend_constants[11] = "g_NaP in component persistent_sodium_current (nanoS)" legend_algebraic[7] = "m_infinity in component persistent_sodium_current_m_gate (dimensionless)" legend_states[2] = "h in component persistent_sodium_current_h_gate (dimensionless)" legend_constants[12] = "theta_m in component persistent_sodium_current_m_gate (millivolt)" legend_constants[13] = "omega_m in component persistent_sodium_current_m_gate (millivolt)" legend_algebraic[2] = "h_infinity in component persistent_sodium_current_h_gate (dimensionless)" legend_algebraic[5] = "tau_h in component persistent_sodium_current_h_gate (millisecond)" legend_constants[14] = "tau_h_max in component persistent_sodium_current_h_gate (millisecond)" legend_constants[15] = "theta_h in component persistent_sodium_current_h_gate (millivolt)" legend_constants[16] = "omega_h in component persistent_sodium_current_h_gate (millivolt)" legend_constants[17] = "g_leak in component leakage_current (nanoS)" legend_constants[18] = "E_leak in component leakage_current (millivolt)" legend_constants[19] = "g_tonic_e in component tonic_current (nanoS)" legend_constants[20] = "E_syn_e in component tonic_current (millivolt)" legend_rates[0] = "d/dt V in component membrane (millivolt)" legend_rates[1] = "d/dt n in component potassium_current_n_gate (dimensionless)" legend_rates[2] = "d/dt h in component persistent_sodium_current_h_gate (dimensionless)" return (legend_states, legend_algebraic, legend_voi, legend_constants) def initConsts(): constants = [0.0] * sizeConstants; states = [0.0] * sizeStates; states[0] = -50.0 constants[0] = 0.021 constants[1] = 0 constants[2] = 50 constants[3] = 28 states[1] = 0.01 constants[4] = -34 constants[5] = -5 constants[6] = 11.2 constants[7] = -85 constants[8] = 10 constants[9] = -29 constants[10] = -4 constants[11] = 2.5 states[2] = 0.92 constants[12] = -45.1 constants[13] = -6 constants[14] = 10000 constants[15] = -53 constants[16] = 6 constants[17] = 2.2 constants[18] = -57.5 constants[19] = 0.2 constants[20] = 0 return (states, constants) def computeRates(voi, states, constants): rates = [0.0] * sizeStates; algebraic = [0.0] * sizeAlgebraic algebraic[1] = 1.00000/(1.00000+exp((states[0]-constants[9])/constants[10])) algebraic[4] = constants[8]/cosh((states[0]-constants[9])/(2.00000*constants[10])) rates[1] = (algebraic[1]-states[1])/algebraic[4] algebraic[2] = 1.00000/(1.00000+exp((states[0]-constants[15])/constants[16])) algebraic[5] = constants[14]/cosh((states[0]-constants[15])/(2.00000*constants[16])) rates[2] = (algebraic[2]-states[2])/algebraic[5] algebraic[10] = constants[19]*(1.00000/1000.00)*(states[0]-constants[20]) algebraic[0] = 1.00000/(1.00000+exp((states[0]-constants[4])/constants[5])) algebraic[3] = constants[3]*(power(algebraic[0], 3.00000))*(1.00000-states[1])*(1.00000/1000.00)*(states[0]-constants[2]) algebraic[7] = 1.00000/(1.00000+exp((states[0]-constants[12])/constants[13])) algebraic[8] = constants[11]*algebraic[7]*states[2]*(1.00000/1000.00)*(states[0]-constants[2]) algebraic[6] = constants[6]*(power(states[1], 4.00000))*(1.00000/1000.00)*(states[0]-constants[7]) algebraic[9] = constants[17]*(1.00000/1000.00)*(states[0]-constants[18]) rates[0] = (-(algebraic[3]+algebraic[8]+algebraic[6]+algebraic[9])+algebraic[10]+constants[1])/constants[0] return(rates) def computeAlgebraic(constants, states, voi): algebraic = array([[0.0] * len(voi)] * sizeAlgebraic) states = array(states) voi = array(voi) algebraic[1] = 1.00000/(1.00000+exp((states[0]-constants[9])/constants[10])) algebraic[4] = constants[8]/cosh((states[0]-constants[9])/(2.00000*constants[10])) algebraic[2] = 1.00000/(1.00000+exp((states[0]-constants[15])/constants[16])) algebraic[5] = constants[14]/cosh((states[0]-constants[15])/(2.00000*constants[16])) algebraic[10] = constants[19]*(1.00000/1000.00)*(states[0]-constants[20]) algebraic[0] = 1.00000/(1.00000+exp((states[0]-constants[4])/constants[5])) algebraic[3] = constants[3]*(power(algebraic[0], 3.00000))*(1.00000-states[1])*(1.00000/1000.00)*(states[0]-constants[2]) algebraic[7] = 1.00000/(1.00000+exp((states[0]-constants[12])/constants[13])) algebraic[8] = constants[11]*algebraic[7]*states[2]*(1.00000/1000.00)*(states[0]-constants[2]) algebraic[6] = constants[6]*(power(states[1], 4.00000))*(1.00000/1000.00)*(states[0]-constants[7]) algebraic[9] = constants[17]*(1.00000/1000.00)*(states[0]-constants[18]) return algebraic def solve_model(): """Solve model with ODE solver""" from scipy.integrate import ode # Initialise constants and state variables (init_states, constants) = initConsts() # Set timespan to solve over voi = linspace(0, 10, 500) # Construct ODE object to solve r = ode(computeRates) r.set_integrator('vode', method='bdf', atol=1e-06, rtol=1e-06, max_step=1) r.set_initial_value(init_states, voi[0]) r.set_f_params(constants) # Solve model states = array([[0.0] * len(voi)] * sizeStates) states[:,0] = init_states for (i,t) in enumerate(voi[1:]): if r.successful(): r.integrate(t) states[:,i+1] = r.y else: break # Compute algebraic variables algebraic = computeAlgebraic(constants, states, voi) return (voi, states, algebraic) def plot_model(voi, states, algebraic): """Plot variables against variable of integration""" import pylab (legend_states, legend_algebraic, legend_voi, legend_constants) = createLegends() pylab.figure(1) pylab.plot(voi,vstack((states,algebraic)).T) pylab.xlabel(legend_voi) pylab.legend(legend_states + legend_algebraic, loc='best') pylab.show() if __name__ == "__main__": (voi, states, algebraic) = solve_model() plot_model(voi, states, algebraic)