On Thu, Mar 3, 2011 at 7:08 AM, luisfe <lftab...@yahoo.es> wrote:
> Could someone highlight why the following happens?
>
> from a sage session, the names that can be imported from
> sage.rings.integer_ring are:
>
> {{{
> EuclideanDomains Z factor
> is_IntegerRing
> IntegerRing ZZ factorization ring
> IntegerRing_class arith gmp_randrange sage
> ParentWithGens clear_mpz_globals init_mpz_globals
> Sequence crt_basis integer_ring_python
> }}}
>
> However, from a sage -ipython session we have the following:
>
> {{{
> IntegerRing clear_mpz_globals factor
> init_mpz_globals
> IntegerRing_class crt_basis gmp_randrange
> is_IntegerRing
> }}}
>
> Imported names and variables defined without def are not available in
> ipython?
I'm not following you
dhcp-172-31-80-120:~ robertwb$ sage -ipython
Python 2.6.4 (r264:75706, Nov 17 2010, 02:06:41)
Type "copyright", "credits" or "license" for more information.
IPython 0.9.1 -- An enhanced Interactive Python.
? -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help -> Python's own help system.
object? -> Details about 'object'. ?object also works, ?? prints more.
In [1]: import sage.all
In [2]: dir(sage.rings.integer_ring)
Out[2]: ['EuclideanDomains', 'IntegerRing', 'IntegerRing_class',
'ParentWithGens', 'Sequence', 'Z', 'ZZ', '__builtins__', '__doc__',
'__file__', '__name__', '__package__', 'clear_mpz_globals',
'crt_basis', 'factor', 'factorization', 'gmp_randrange',
'init_mpz_globals', 'integer_ring_python', 'is_IntegerRing', 'ring',
'sage']
> I suspect that this has to do with cython and extension modules and
> has a bad impact on lazy_import since not all names can be
> lazy_imported.
Why? They look like they're all there to me.
> Moreover, on a pure ipython session it is trivial to
> get segfaults unless one import all from sage.all
>
> {{{
> $ sage -ipython
> In [1]: from sage.rings.integer_ring import *
> ...
> AttributeError: 'module' object has no attribute 'ZZ'
> In [2]: from sage.rings.integer_ring import *
>
> In [3]: IntegerRing()
>
>
> ------------------------------------------------------------
> Unhandled SIGSEGV: A segmentation fault occurred in Sage.
> This probably occurred because a *compiled* component
> of Sage has a bug in it (typically accessing invalid memory)
> and is not properly wrapped with sig_on(), sig_off().
> You might want to run Sage under gdb with 'sage -gdb' to debug this.
> Sage will now terminate (sorry).
> ------------------------------------------------------------
> }}}
Yes, this fragility is a known bug, and one of the reasons I mentioned
doing a lazy import of everything the global namespace is not going to
work.
- Robert
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