Python 如何在cython中从c数组公开numpy数组?
我希望它返回一个numpy数组。我怎么做 现在我必须做些什么Python 如何在cython中从c数组公开numpy数组?,python,numpy,cython,Python,Numpy,Cython,我希望它返回一个numpy数组。我怎么做 现在我必须做些什么 cpdef myf(): # pd has to be a c array. # Because it will then be consumed by some c function. cdef double pd[8000] # Do something with pd ... # Get a memoryview. cdef double[:] pd_view = pd
cpdef myf():
# pd has to be a c array.
# Because it will then be consumed by some c function.
cdef double pd[8000]
# Do something with pd
...
# Get a memoryview.
cdef double[:] pd_view = pd
# Coercion the memoryview to numpy array. Not working.
ret = np.asarray(pd)
return ret
在这里的
memview
示例中
我可以从carr\u视图
中创建一个numpy数组,carr
上的内存视图,一个C数组
# Memoryview on a C array
cdef int carr[3][3][3]
cdef int [:, :, :] carr_view = carr
carr_view[...] = narr_view # np.arange(27, dtype=np.dtype("i")).reshape((3, 3, 3))
carr_view[0, 0, 0] = 100
如果您只是在函数中声明数组,为什么不首先将其设置为numpy数组,那么当您需要c数组时,只需获取数据指针即可
# print np.array(carr) # cython error
print 'numpy array on carr_view'
print np.array(carr_view)
print np.array(carr_view).sum() # match sum3d(carr)
# or np.asarray(carr_view)
print 'numpy copy from carr_view'
carr_copy = np.empty((3,3,3))
carr_copy[...] = carr_view[...] # don't need indexed copy
print carr_copy
print carr_copy.sum() # match sum3d(carr)
我打错了字,
ret=np.asarray(pd_视图)
# print np.array(carr) # cython error
print 'numpy array on carr_view'
print np.array(carr_view)
print np.array(carr_view).sum() # match sum3d(carr)
# or np.asarray(carr_view)
print 'numpy copy from carr_view'
carr_copy = np.empty((3,3,3))
carr_copy[...] = carr_view[...] # don't need indexed copy
print carr_copy
print carr_copy.sum() # match sum3d(carr)
cimport numpy as np
import numpy as np
def myf():
cdef np.ndarray[double, ndim=1, mode="c"] pd_numpy = np.empty(8000)
cdef double *pd = &pd_numpy[0]
# Do something to fill pd with values
for i in range(8000):
pd[i] = i
return pd_numpy