我有这个方程组:
def Diffeq(v,t, lam, gam,a):
c=[i for i in range(0,len(v))]
vdot = np.empty_like(v)
for i in range(0,len(v)):
if i == 0:
vdot[0] = gam*c[1]*v[1]
elif i == (len(v)-1):
vdot[i] = lam*a[i-1]*v[i-1] - (lam*a[i]+gam*c[i])*v[i]
else:
vdot[i]= lam*a[i-1]*v[i-1] - (lam*a[i]+gam*c[i])*v[i]+
gam*c[i+1]*v[i+1]
return vdot
其中lambda,gamma和a是以下参数集(N = 1000):
a = [6*i*(N-i)/(N-1.0) for i in range (0,N+1)]
gamma = 1
lam = 2
如果我打电话给
t = np.linspace(0,3,100)
incond=np.array([0.0]*(N+1) #from 0 to 1000 included
incond[i0] =1.0
y = odeint(Diffeq, incond, t, args=(lam,gamma,a))
然后我尝试绘制y的期望值:
finalv = np.array([0.0]*100)
for time in range(0,100):
for k in range(0,N+1):
finalv[time] = finalv[time] + (k)*y[time][k]
如果我想将t间隔更改为
t = linspace(0,50,100)
有时候,如果我对a的值进行一些调整,则会收到此运行时警告:
/home/myub/Desktop/Odeintegration.py:79: RuntimeWarning: overflow
encountered in double_scalars