Question

PYTHON 相关我这个哪里出错了

代码是
from qutip import*
from math import*
import numpy as np
wc=1.0*2*pi
wa=1.0*2*pi
N=20
g=np.linspace(0,2.5,50)*2*pi
a=tensor(destroy(N),qeye(2))
sm=tensor(qeye(N),destroy(2))
nc=a.dag()*a
na=sm.dag()*sm
na_expt=zeros(len(g))
nc_expt=zeros(len(g))
for k in range(len(g)):
H=wc*nc+wa*na+g[k]*(a.dag()+a)*(sm+sm.dag())
ekets,evals=H.eigenstates()
psi_gnd=ekets[0.0]
na_expt[k]=expect(na,psi_gnd)
nc_expt[k]=expect(nc,psi_gnd)
rho_cavity=qutip.ptrace(psi_gnd,0.0)
xvec=np.linspace(-7.5,7.5,200)
w=winger(rho_cavity,xvec,xvec)

运行后出现Traceback (most recent call last):
File "C:\Python27\Lib\site-packages\pythonwin\pywin\framework\scriptutils.py", line 323, in RunScript
debugger.run(codeObject, __main__.__dict__, start_stepping=0)
File "C:\Python27\Lib\site-packages\pythonwin\pywin\debugger\__init__.py", line 60, in run
_GetCurrentDebugger().run(cmd, globals,locals, start_stepping)
File "C:\Python27\Lib\site-packages\pythonwin\pywin\debugger\debugger.py", line 655, in run
exec cmd in globals, locals
File "C:\Users\wqh\Documents\pig2.py", line 1, in <module>
from qutip import*
File "C:\Python27\lib\site-packages\qutip\qobj.py", line 1274, in ptrace
return Q.ptrace(sel)
AttributeError: 'numpy.float64' object has no attribute 'ptrace'

请问是哪错了

Answer 1

rho_cavity=qutip.ptrace(psi_gnd,0.0)

我没有你的库，但我觉得你的方法调用错误了，改成下面的内容试一下。

rho_cavity=qutip.ptrace.ptrace(psi_gnd,0.0)

追问

改成你说的那样了 还是出错这次成了 AttributeError: 'function' object has no attribute 'ptrace'这了

追答

这个问题就是你对方法的调用出现了问题，我没有你的环境不好重现，你自己上网找一下对应函数的说明看一下，用yahoo、bing（有google最好）啥的搜一下相关的函数。