Python 将一个类声明为另一个类中的对象

我在cython中重新编写了一段python代码，由于我是新手，所以遇到了一些问题。我的代码如下：

  __Pyx_XDECREF_SET(cosmology, ((struct __pyx_obj_5tools_cosmology *)__pyx_t_3));

tools.pyx

import numpy as np
import copy
cimport numpy as np
ctypedef np.double_t DTYPE_T
cpdef double std_G,v_c
std_G=4.3e-9 # Newton's const   in Mpc (km/s)^2 M_sol^{-1}
v_c = 299792.458 #km/s

cdef extern from "math.h":
    double log(double) nogil
    double sqrt(double) nogil


cdef extern from "gsl/gsl_math.h":
    ctypedef struct gsl_function:
        double (* function) (double x, void * params)
        void * params

cdef extern from "gsl/gsl_integration.h":
    ctypedef struct gsl_integration_workspace
    gsl_integration_workspace *  gsl_integration_workspace_alloc(size_t n)
    void  gsl_integration_workspace_free(gsl_integration_workspace * w)
    int  gsl_integration_qags(const gsl_function * f, double a, double b, double epsabs, double epsrel, size_t limit, gsl_integration_workspace * workspace, double *result, double *abserr)
 cdef double do_callback(double x, void* params): 
      return (<ComovingDistMemoization>params).eval(x) 


 cdef class ComovingDistMemoization(object):
 cdef list _memotable
 def __init__(self, cosmology cosmo, memotable = None):

     if memotable is None:
        self._memotable = []

     self._memotable = memotable
     self.cosmology = cosmo
 def __call__(self, double z):


    if z in self._memotable:
        return self._memotable[z]

    def eval(z):

        return 1./sqrt(self.cosmology.hubble2(z))
    cdef gsl_integration_workspace* w =gsl_integration_workspace_alloc(1000)
    cdef gsl_function F            

    F.function = &do_callback 
    F.params = <void*>self 
    cdef double result = 3, error = 5
    cdef double y, err, dist
    gsl_integration_qags (&F, 0, z, 0, 1e-7, 1000, w, &result, &error) 
    y, err = result, error 

    gsl_integration_workspace_free(w) 

    dist = self.cosmology.v_c * y  #to get proper units, ie to put in the hubble length

    self._memotable[z] = dist

    return dist


cdef class cosmology(object):
cdef public double omega_m, omega_l, h, w, omega_r, G, v_c
cdef ComovingDistMemoization ComovingDistMemoization
def __init__(self,double omega_m = 0.3, double omega_l = 0.7, double h = 0.7, double w = -1, double omega_r = 0., double G = std_G):

    self.omega_m = omega_m
    self.omega_l = omega_l
    self.omega_r = omega_r
    self.h = h
    self.w = w
    self.G = G
    self.v_c = v_c

    self.comovingdist = ComovingDistMemoization(self)
def __copy__(self):

    return cosmology(omega_m = self.omega_m, omega_l = self.omega_l, h = self.h, w = self.w, omega_r = self.omega_r, G = self.G)

property H0:
   def __get__(self):
       return 100*self.h  #km/s/MPC

def hubble2(self, double z):
    cdef double inv_a
    inv_a = 1.+z
    return (self.omega_r*inv_a**4 + self.omega_m*inv_a**3 + \
              self.omega_l*(inv_a**(3*(1+self.w))) + (1 - self.omega_m - self.omega_l - self.omega_r)*inv_a**2)*self.H0**2

property hubble_length:
    def __get__(self):
        return self.v_c / self.H0

def rho_crit(self, double z):
    return 3.*self.hubble2(z)/(8*np.pi*self.G)


def angulardist(self, double z, double z2 = None):

    if z2 is None:
        return self.comovingdist(z) / (1+z)

    return (self.comovingdist(z2) - self.comovingdist(z)) / (1+z2)
class CosmologyFixedException(Exception): pass
cdef class CosmologySingleton(object):
cdef object _cosmology,startCosmology
cdef bint isMutable
cdef cosmology cosmology
def __cinit__(self, startCosmology = None, isMutable = True):
    self.isMutable = isMutable
    if startCosmology is None:
        self._cosmology = cosmology()
    else:
        self._cosmology = copy.copy(startCosmology)
def get_cosmology(self):
    return copy.copy(self._cosmology)
def set_cosmology(self, newcosmo):
    if not self.isMutable:
        raise CosmologyFixedException
    self._cosmology = copy.copy(newcosmo)
cosmology = property(get_cosmology, set_cosmology)
def __getattr__(self, name):
    return getattr(self._cosmology, name)

但是当我编译

c

代码时，我得到了以下错误：

 gcc -m64 -pthread -fno-strict-aliasing -Wstrict-prototypes -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -I/usr/include -I/vol/dalek/anaconda/include/python2.7 -c tools.c -o build/temp.linux-x86_64-2.7/tools.o

错误

tools.c: In function ‘inittools’:
tools.c:6880:3: error: ‘cosmology’ undeclared (first use in this function)
tools.c:6880:3: note: each undeclared identifier is reported only once for each function it appears in

tools.c代码中的参考行如下所示：

  __Pyx_XDECREF_SET(cosmology, ((struct __pyx_obj_5tools_cosmology *)__pyx_t_3));

---

类应该如何在另一个类中定义和声明，特别是作为一个对象？

@angs Cython应该支持C结构并在python和C之间建立连接，因此它也应该遵循C结构。这个问题对您仍然相关吗？看来这个方法可以简化。。。你有更简洁的例子吗？@saullocastrog'day！你有答案吗？还是解释得不好？解释得不好，例子太长。。。也许你可以把这个缩短一点…@SaulloCastro我同意！我需要修改解释！：P