首先让我道歉，如果这是一个简单的问题，或者之前已经回答过。事实是，我甚至不知道如何对我的问题进行搜索。
假设我有以下一组耦合ODE：
dN / dt =（h N（t）+ i Q（t））* G（t）
dQ / dt =（j N（t）+ l Q（t））* G（t）
这是我用来绘制ODE的代码：
import numpy
import matplotlib.pyplot as plt
from scipy import constants
from scipy.integrate import odeint
plt.ion()
#-------------------------------------INITIAL CONSTANT PARAMETERS-------------------------------------------
wavelenght = 1908e-9 #meter
wp0 = 300e-6 #laser beam diameter
conc = 1.0 #dopant concentration
crosssection = 6.5e-14 #spectroscopic absorption cross section in m2
lifetime = 230e-6 #upper lifetime
cavity_l = 200e-3 #total lenght of cavity in mm
gain_l = 10e-3 #lenght of gain medium
n_gain = 1.82 #refraction index gain medium
R_OC = 0.3 #reflectivity OC
additional_loss = 0.05 #additional losses
loss_time_max = 10.0e5 #max loss instroduced by q-switch
r = 10 #times above threshold laser is pumped before q-switch opens
t0 = 0
tf = 20e-12
tpulse = 1e-9
ttotal = 10e-9
#-------------------------------------INITIAL VARIABLE PARAMETERS-------------------------------------------
#number density from concentration percentage
Ntotalyag = conc*3*4.55/((3*88.9 + 5*27.0 + 12*16.0)*constants.m_p)
#nominator: 3 at of Y * mass density of Y3Al5O12
#denominator: mass of the Y3Al5O12 unit, calculated from the relative atomic weights and the proton mass
beam_area = numpy.pi*(wp0/2)*(wp0/2)
roundtrip_time = 2.0*((cavity_l-gain_l)/constants.c)+(n_gain*gain_l/constants.c) #time for light to travel back and forth inside cavity
losscoef = - numpy.log(R_OC) + additional_loss
popinversionthreshold = losscoef * beam_area/(2.0 * crosssection)
Wp = 0.0 #pumping rate
#-------------------------------------FUNCTIONS-------------------------------------------
def f(y, t, L):
q = y[0]
DeltaN = y[1]
if t > tf:
losscoef_t = 0.0
else:
losscoef_t = loss_time_max - ((loss_time_max - losscoef)/(tf))*t
# gupta Handbook of photonics ch about micro laser
L= L.append(losscoef_t)
f0 = q*((DeltaN/popinversionthreshold)-1.0) * losscoef_t/roundtrip_time
f1 = Wp*(Ntotalyag-DeltaN) - q*((DeltaN*losscoef_t)/(popinversionthreshold*roundtrip_time)) - DeltaN/lifetime
return [f0, f1]
#-------------------------------------ODE SOLVING 1-------------------------------------------
# initial conditions
q0 = 0.01 # initial photon population
DeltaN0 = r * popinversionthreshold # initial inverted population
y0 = [q0, DeltaN0] # initial condition vector
t = numpy.linspace(0, ttotal, 1000) # time grid
L = []
# solve the DEs
soln = odeint(f, y0, t, args=(L,))
Q = soln[:, 0]
N = soln[:, 1]
#-------------------------------------PLOTS---------------------------------------------------
plt.figure()
plt.plot(t, Q, label='Photon')
plt.plot(t, N, label='Population')
plt.legend(loc=0)
以上不起作用，因为我假设我可以计算每个时间步t的G（t），但我注意到len（L）与Q或N不同。 基本上我的问题是，如何计算ODE上随时间步长变化的参数？
非常感谢