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https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision 9e456bc70e7bc9ee9726d356d7167457e585fd4c authored by Raymond Hettinger on 24 February 2019, 19:44:55 UTC, committed by Miss Islington (bot) on 24 February 2019, 19:44:55 UTC 
bpo-36018: Add properties for mean and stdev (GH-12022)
 


Responding to suggestions on the tracker and some off-line suggestions.

Davin suggested that english named accessors instead of greek letters would result in more intelligible user code. Steven suggested that the parameters still need to be *mu* and *theta* which are used elsewhere (and I noted those parameter names are used in linked-to resources). 

Michael suggested proving-out the API by seeing whether it generalized to *Lognormal*.  I did so and found that Lognormal distribution parameters *mu* and *sigma*  do not represent the mean and standard deviation of the lognormal distribution (instead, they are for the underlying regular normal distribution).

Putting these ideas together, we have NormalDist parameterized by *mu* and *sigma* but offering English named properties for accessors.  That gives lets us match other API that access mu and sigma, it matches the external resources on the topic, gives us clear english names in user code. The API extends nicely to LogNormal where the parameters and the summary statistic accessors are not the same.


https://bugs.python.org/issue36018
1 parent a875ea5
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Tip revision: 9e456bc70e7bc9ee9726d356d7167457e585fd4c authored by Raymond Hettinger on 24 February 2019, 19:44:55 UTC
bpo-36018: Add properties for mean and stdev (GH-12022)
Tip revision: 9e456bc
odictobject.h 
#ifndef Py_ODICTOBJECT_H
#define Py_ODICTOBJECT_H
#ifdef __cplusplus
extern "C" {
#endif


/* OrderedDict */
/* This API is optional and mostly redundant. */

#ifndef Py_LIMITED_API

typedef struct _odictobject PyODictObject;

PyAPI_DATA(PyTypeObject) PyODict_Type;
PyAPI_DATA(PyTypeObject) PyODictIter_Type;
PyAPI_DATA(PyTypeObject) PyODictKeys_Type;
PyAPI_DATA(PyTypeObject) PyODictItems_Type;
PyAPI_DATA(PyTypeObject) PyODictValues_Type;

#define PyODict_Check(op) PyObject_TypeCheck(op, &PyODict_Type)
#define PyODict_CheckExact(op) (Py_TYPE(op) == &PyODict_Type)
#define PyODict_SIZE(op) PyDict_GET_SIZE((op))

PyAPI_FUNC(PyObject *) PyODict_New(void);
PyAPI_FUNC(int) PyODict_SetItem(PyObject *od, PyObject *key, PyObject *item);
PyAPI_FUNC(int) PyODict_DelItem(PyObject *od, PyObject *key);

/* wrappers around PyDict* functions */
#define PyODict_GetItem(od, key) PyDict_GetItem(_PyObject_CAST(od), key)
#define PyODict_GetItemWithError(od, key) \
    PyDict_GetItemWithError(_PyObject_CAST(od), key)
#define PyODict_Contains(od, key) PyDict_Contains(_PyObject_CAST(od), key)
#define PyODict_Size(od) PyDict_Size(_PyObject_CAST(od))
#define PyODict_GetItemString(od, key) \
    PyDict_GetItemString(_PyObject_CAST(od), key)

#endif

#ifdef __cplusplus
}
#endif
#endif /* !Py_ODICTOBJECT_H */
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