# Size of variable arrays:
sizeAlgebraic = 0
sizeStates = 0
sizeConstants = 15
from math import *
from numpy import *

def createLegends():
    legend_states = [""] * sizeStates
    legend_rates = [""] * sizeStates
    legend_algebraic = [""] * sizeAlgebraic
    legend_voi = ""
    legend_constants = [""] * sizeConstants
    legend_constants[0] = "Rsas in component ParaSys (UnitR)"
    legend_constants[1] = "Csas in component ParaSys (UnitC)"
    legend_constants[2] = "Lsas in component ParaSys (UnitL)"
    legend_constants[3] = "P0sas in component ParaSys (UnitP)"
    legend_constants[4] = "Q0sas in component ParaSys (UnitQ)"
    legend_constants[5] = "Rsat in component ParaSys (UnitR)"
    legend_constants[6] = "Csat in component ParaSys (UnitC)"
    legend_constants[7] = "Lsat in component ParaSys (UnitL)"
    legend_constants[8] = "P0sat in component ParaSys (UnitP)"
    legend_constants[9] = "Q0sat in component ParaSys (UnitQ)"
    legend_constants[10] = "Rsar in component ParaSys (UnitR)"
    legend_constants[11] = "Rscp in component ParaSys (UnitR)"
    legend_constants[12] = "Rsvn in component ParaSys (UnitR)"
    legend_constants[13] = "Csvn in component ParaSys (UnitC)"
    legend_constants[14] = "P0svn in component ParaSys (UnitP)"
    return (legend_states, legend_algebraic, legend_voi, legend_constants)

def initConsts():
    constants = [0.0] * sizeConstants; states = [0.0] * sizeStates;
    constants[0] = 0.003
    constants[1] = 0.08
    constants[2] = 0.000062
    constants[3] = 100.
    constants[4] = 0.
    constants[5] = 0.05
    constants[6] = 1.6
    constants[7] = 0.0017
    constants[8] = 100.
    constants[9] = 0.
    constants[10] = 0.5
    constants[11] = 0.52
    constants[12] = 0.075
    constants[13] = 20.5
    constants[14] = 0.
    return (states, constants)

def computeRates(voi, states, constants):
    rates = [0.0] * sizeStates; algebraic = [0.0] * sizeAlgebraic
    return(rates)

def computeAlgebraic(constants, states, voi):
    algebraic = array([[0.0] * len(voi)] * sizeAlgebraic)
    states = array(states)
    voi = array(voi)
    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)