Hi,
On Monday 21 May 2012, Oleksandr Kazymyrov wrote:
> Dear all,
>
> 1. Why important next functions?
> k.a_times_b_minus_c
> k.a_times_b_plus_c
> k.c_minus_a_times_b
These shouldn't exist I'd say. The reason they do exist is that when I wrapped
Givaro it provided these functions so I figured I might as well provide them.
So what we should do is deprecate these functions and replace them by
functions starting with "_" indicating, that they are kinda internal. Can you
open a ticket?
> sage: k.some_elements ?
> ...
> Returns a collection of elements of this finite field *for use
> in unit testing.*
The function is indeed used in unitests as confirmed by
search_src("some_elements"). Perhaps it should start with an underscore?
> Why this function are defined as public?
> 2. Also a few misunderstanding functions
>
> - sage: *k.cardinality* ?
> Type: builtin_function_or_method
> Base Class: <type 'builtin_function_or_method'>
> String Form: <built-in method cardinality of
> FiniteField_givaro_with_category object at 0xbb0eaac>
> Namespace: Interactive
> Definition: k.cardinality(self)
> Docstring:
> Return the order of this finite field (*same as self.order()*).
Why is this confusing?
> - sage: *k.cayley_graph() *
>
> --------------------------------------------------------------------------
> - AttributeError Traceback (most recent call
> last)
>
> /home/hamsin/<ipython console> in <module>()
>
>
> /home/hamsin/bin/sage/local/lib/python2.7/site-packages/sage/categories/se
> migroups.pyc in cayley_graph(self, side, simple, elements, generators,
> connecting_set) 284 generators = connecting_set
> 285 if generators is None:
> --> 286 generators = self.semigroup_generators()
> 287 if isinstance(generators, (list, tuple)):
> 288 generators = dict((self(g), self(g)) for g in
> generators)
>
>
> /home/hamsin/bin/sage/local/lib/python2.7/site-packages/sage/structure/par
> ent.so in sage.structure.parent.Parent.__getattr__
> (sage/structure/parent.c:6805)()
>
>
> /home/hamsin/bin/sage/local/lib/python2.7/site-packages/sage/structure/par
> ent.so in sage.structure.parent.getattr_from_other_class
> (sage/structure/parent.c:3248)()
>
> AttributeError: 'FiniteField_givaro_with_category' object has no
> attribute 'semigroup_generators'
This is a bug, i.e., K inherits the generic cayley_graph() but does not
provide all the machinery needed to make it work.
> - sage: *k.has_base()*
> *True*
> sage: *k.has_base* ?
> Type: builtin_function_or_method
> Base Class: <type 'builtin_function_or_method'>
> String Form: <built-in method has_base of
> FiniteField_givaro_with_category object at 0xbb0eaac>
> Namespace: Interactive
> Definition: k.has_base(self, category=None)
> *??????*
The base of GF(p^k) is GF(p), the lack of documentation is a bug :)
> *
> - sage: *k.ngens* *?*
> Type: builtin_function_or_method
> Base Class: <type 'builtin_function_or_method'>
> String Form: <built-in method ngens of FiniteField_givaro_with_category
> object at 0xbb0eaac>
> Namespace: Interactive
> Definition: k.ngens(self)
> Docstring:
> The number of generators of the finite field. * Always 1.*
This is a generic function provided for compatibility with other parents in
Sage.
> *
> *
> - sage: *k.normalize_names ?*
> Type: builtin_function_or_method
> Base Class: <type 'builtin_function_or_method'>
> String Form: <built-in method normalize_names of
> FiniteField_givaro_with_category object at 0xbb0eaac>
> Namespace: Interactive
> Definition: k.normalize_names(self, ngens, names=None)
>
> sage: k.normalize_names()
This is a generic method that perhaps could be private, i.e.,
"_normalize_names()" or moved somewhere else?
> - sage: *k.on*
> k.one k.one_element
> sage: k.one ?
> Type: builtin_function_or_method
> Base Class: <type 'builtin_function_or_method'>
> String Form: <built-in method one_element of
> FiniteField_givaro_with_category object at 0xbb0eaac>
> Namespace: Interactive
> Definition: k.one(self)
> Docstring:
> Return the one element of this ring (cached), if it exists.
>
> EXAMPLES:
>
> sage: ZZ.*one_element()*
> 1
> sage: QQ.*one_element()*
> 1
> sage: QQ['x'].*one_element()*
> 1
>
> The result is cached:
>
> sage: ZZ.*one_element() *is *ZZ.one_element()*
> True
>
>
>
> - sage: *k.zero ? *
> Type: builtin_function_or_method
> Base Class: <type 'builtin_function_or_method'>
> String Form: <built-in method zero_element of
> FiniteField_givaro_with_category object at 0xbb0eaac>
> Namespace: Interactive
> Definition: k.zero(self)
> Docstring:
> Return the zero element of this ring (cached).
>
> EXAMPLES:
>
> sage: *ZZ.zero_element()*
> 0
> sage: *QQ.zero_element()*
> 0
> sage: QQ['x'].*zero_element()*
> 0
>
> The result is cached:
>
> sage: ZZ.*zero_element()* is ZZ.*zero_element()*
> True
These are aliases, I don't find this confusing.
Anyway, do you want to provide (documentation) patches for the issues you
discovered?
Cheers,
Martin
--
name: Martin Albrecht
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