# Size of variable arrays: sizeAlgebraic = 10 sizeStates = 3 sizeConstants = 7 from math import * from numpy import * def createLegends(): legend_states = [""] * sizeStates legend_rates = [""] * sizeStates legend_algebraic = [""] * sizeAlgebraic legend_voi = "" legend_constants = [""] * sizeConstants legend_algebraic[0] = "u_in_e in component Environment (J_per_C)" legend_voi = "t in component Environment (second)" legend_states[0] = "v_1_e in component Voice_coil_equations (C_per_s)" legend_algebraic[8] = "a_1_e in component Voice_coil_equations (C_per_s2)" legend_states[1] = "q_C_m in component Voice_coil_equations (metre)" legend_states[2] = "v_2_m in component Voice_coil_equations (m_per_s)" legend_algebraic[9] = "a_2_m in component Voice_coil_equations (m_per_s2)" legend_algebraic[2] = "u_R_e in component Voice_coil_equations (J_per_C)" legend_algebraic[6] = "u_L_e in component Voice_coil_equations (J_per_C)" legend_algebraic[4] = "u_1_e in component Voice_coil_equations (J_per_C)" legend_algebraic[1] = "u_2_m in component Voice_coil_equations (J_per_m)" legend_algebraic[3] = "u_C_m in component Voice_coil_equations (J_per_m)" legend_algebraic[5] = "u_R_m in component Voice_coil_equations (J_per_m)" legend_algebraic[7] = "u_L_m in component Voice_coil_equations (J_per_m)" legend_constants[0] = "E_1 in component Voice_coil_equations (J_per_C2)" legend_constants[1] = "E_2 in component Voice_coil_equations (J_per_m2)" legend_constants[2] = "R_1_e in component Voice_coil_equations (Js_per_C2)" legend_constants[3] = "R_2_m in component Voice_coil_equations (Js_per_m2)" legend_constants[4] = "L_1_e in component Voice_coil_equations (Js2_per_C2)" legend_constants[5] = "L_2_m in component Voice_coil_equations (Js2_per_m2)" legend_constants[6] = "Bl in component Voice_coil_equations (Js_per_C_m)" legend_rates[0] = "d/dt v_1_e in component Voice_coil_equations (C_per_s)" legend_rates[1] = "d/dt q_C_m in component Voice_coil_equations (metre)" legend_rates[2] = "d/dt v_2_m in component Voice_coil_equations (m_per_s)" return (legend_states, legend_algebraic, legend_voi, legend_constants) def initConsts(): constants = [0.0] * sizeConstants; states = [0.0] * sizeStates; states[0] = 0 states[1] = 0 states[2] = 0 constants[0] = 1 constants[1] = 100 constants[2] = 5 constants[3] = 0.4 constants[4] = 0.2 constants[5] = 0.01 constants[6] = 6 return (states, constants) def computeRates(voi, states, constants): rates = [0.0] * sizeStates; algebraic = [0.0] * sizeAlgebraic rates[1] = states[2] algebraic[0] = 50.0000*sin(50.0000*2.00000* pi*voi) algebraic[2] = constants[2]*states[0] algebraic[4] = constants[6]*states[2] rootfind_0(voi, constants, rates, states, algebraic) rootfind_1(voi, constants, rates, states, algebraic) rates[0] = algebraic[8] algebraic[1] = constants[6]*states[0] algebraic[3] = constants[1]*states[1] algebraic[5] = constants[3]*states[2] rootfind_2(voi, constants, rates, states, algebraic) rootfind_3(voi, constants, rates, states, algebraic) rates[2] = algebraic[9] return(rates) def computeAlgebraic(constants, states, voi): algebraic = array([[0.0] * len(voi)] * sizeAlgebraic) states = array(states) voi = array(voi) algebraic[0] = 50.0000*sin(50.0000*2.00000* pi*voi) algebraic[2] = constants[2]*states[0] algebraic[4] = constants[6]*states[2] algebraic[1] = constants[6]*states[0] algebraic[3] = constants[1]*states[1] algebraic[5] = constants[3]*states[2] return algebraic initialGuess0 = None def rootfind_0(voi, constants, states, algebraic): """Calculate value of algebraic variable for DAE""" from scipy.optimize import fsolve global initialGuess0 if initialGuess0 is None: initialGuess0 = 0.1 if not iterable(voi): algebraic[6] = fsolve(residualSN_0, initialGuess0, args=(algebraic, voi, constants, rates, states), xtol=1E-6) initialGuess0 = algebraic[6] else: for (i,t) in enumerate(voi): algebraic[6][i] = fsolve(residualSN_0, initialGuess0, args=(algebraic[:,i], voi[i], constants, rates, states[:,i]), xtol=1E-6) initialGuess0 = algebraic[6][i] def residualSN_0(algebraicCandidate, algebraic, voi, constants, rates, states): algebraic[6] = algebraicCandidate return (algebraic[0]) - (algebraic[2]+algebraic[6]+algebraic[4]) initialGuess1 = None def rootfind_1(voi, constants, states, algebraic): """Calculate value of algebraic variable for DAE""" from scipy.optimize import fsolve global initialGuess1 if initialGuess1 is None: initialGuess1 = 0.1 if not iterable(voi): algebraic[8] = fsolve(residualSN_1, initialGuess1, args=(algebraic, voi, constants, rates, states), xtol=1E-6) initialGuess1 = algebraic[8] else: for (i,t) in enumerate(voi): algebraic[8][i] = fsolve(residualSN_1, initialGuess1, args=(algebraic[:,i], voi[i], constants, rates, states[:,i]), xtol=1E-6) initialGuess1 = algebraic[8][i] def residualSN_1(algebraicCandidate, algebraic, voi, constants, rates, states): algebraic[8] = algebraicCandidate return (algebraic[6]) - (constants[4]*algebraic[8]) initialGuess2 = None def rootfind_2(voi, constants, states, algebraic): """Calculate value of algebraic variable for DAE""" from scipy.optimize import fsolve global initialGuess2 if initialGuess2 is None: initialGuess2 = 0.1 if not iterable(voi): algebraic[7] = fsolve(residualSN_2, initialGuess2, args=(algebraic, voi, constants, rates, states), xtol=1E-6) initialGuess2 = algebraic[7] else: for (i,t) in enumerate(voi): algebraic[7][i] = fsolve(residualSN_2, initialGuess2, args=(algebraic[:,i], voi[i], constants, rates, states[:,i]), xtol=1E-6) initialGuess2 = algebraic[7][i] def residualSN_2(algebraicCandidate, algebraic, voi, constants, rates, states): algebraic[7] = algebraicCandidate return (algebraic[1]) - (algebraic[3]+algebraic[5]+algebraic[7]) initialGuess3 = None def rootfind_3(voi, constants, states, algebraic): """Calculate value of algebraic variable for DAE""" from scipy.optimize import fsolve global initialGuess3 if initialGuess3 is None: initialGuess3 = 0.1 if not iterable(voi): algebraic[9] = fsolve(residualSN_3, initialGuess3, args=(algebraic, voi, constants, rates, states), xtol=1E-6) initialGuess3 = algebraic[9] else: for (i,t) in enumerate(voi): algebraic[9][i] = fsolve(residualSN_3, initialGuess3, args=(algebraic[:,i], voi[i], constants, rates, states[:,i]), xtol=1E-6) initialGuess3 = algebraic[9][i] def residualSN_3(algebraicCandidate, algebraic, voi, constants, rates, states): algebraic[9] = algebraicCandidate return (algebraic[7]) - (constants[5]*algebraic[9]) 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)