用Cython C code语言编译失败，类型化memoryviews [英] cython C code compilation fails with typed memoryviews

问题描述

以下code编译没有在用Cython问题：

The following code compiles without issues in cython:

cdef class Double:
    cdef double v
    def __init__(self, double v):
        self.v = v
    cdef double incr(self) nogil:
        self.v += 1
        return self.v

cdef int f(Double[:] xs):
    cdef int i, N
    N = xs.shape[0]
    for i in range(N):
        xs[i].incr()
    return 0

然而，当我尝试编译生成的C code，gcc编译器将停止与一个错误：

However, when I try to compile the generated C code, the gcc compiler stops with an error:

test.c: In function '__pyx_f_4test_f':
test.c:1491:55: error: 'PyObject {aka struct _object}' has no member named '__pyx_vtab'
     ((struct __pyx_vtabstruct_4test_Double *)__pyx_t_3->__pyx_vtab)->incr(__pyx_t_3);

在哪里的错误，我在做什么？需要注意的是，当我使用标准memorytypes（例如，使用同一code没有任何问题，双重[：] XS 参数在˚F功能）。

此外，有没有办法用来释放里面的的吉˚F函数双[：] ？如果我尝试了，我得到一个错误信息

Additionally, is there a way to release the gil inside the f function with Double[:]? If I try that, I get an error message

test.pyx:13:10: Cannot access buffer with object dtype without gil

纵观产生code，我看到了几个电话到 __ Pyx_INCREF 和 __ Pyx_DECREF ，其中然而，似乎并不需要我。

Looking at the generated code, I see a couple of calls to __Pyx_INCREF and __Pyx_DECREF, which however seems not needed to me.

修改

经过一些讨论，我现在可以找到变通方法，并能够编译C code：例如使用对象[：] XS 在函数定义中，然后抹上（小于双＆GT;（XS [I]））INCR（）在for循环。然而，这些解决方法引入更蟒蛇互动，这是真的，我想什么来避免。

Following some discussion, I can now find workarounds and be able to compile the C code: for example use object[:] xs in the function definition, and then cast (<Double>(xs[i])).incr() in the for loop. However, these workaround introduce even more python interaction, which is really what I would like to avoid.

在更一般的问题是：有在用Cython的方式来处理的CDEF类同质列表（类型化的缓冲区或类似）所以，没有蟒开销和GIL可以释放？的

In more general terms, the question is: is there a way in cython to deal with a homogeneous list of cdef class (a typed buffer or similar) so that there is no python overhead and the GIL can be released?

推荐答案

请检查这个话题，你的情况可能是类似于它：
<一href=\"http://stackoverflow.com/questions/31119510/cython-have-sequence-of-extension-types-as-attribute-of-another-extension-type\">Cython:有扩展类型为能够访问CDEF方法的另一个扩展类型属性的序列

Please check this topic, your case is probably similar to it: Cython: have sequence of Extension Types as attribute of another Extension Type with access to cdef methods

请尝试也为谷歌搜索 __ pyx_vtab - 搜索结果显示了谁也有类似的问题，我查了第一个简单，看起来有些解决方案是有太多的问题的人民：
https://groups.google.com/forum/#​​!topic/cython -Users / 3tUDIc11Xak

Please also try Googling for __pyx_vtab - search results shows questions from peoples who has similar problem, I checked first one briefly and looks that some solution is there too: https://groups.google.com/forum/#!topic/cython-users/3tUDIc11Xak

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