On Feb 4, 6:18 am, Pierre <[email protected]> wrote:
> hi,
Hi Pierre,
> i'm sure this used to work with earlier versions of sage, but now i'm
> getting this:
>
> sage: R.<a,b> = QQ[]
> sage: I= [a-b, a+2*b]*R
> sage: I.groebner_basis()
<SNIP>
> RuntimeError: Singular error:
> ? cannot open `general.lib`
> ? error occurred in STDIN line 2: `LIB "general.lib";`
There are two potential problems here:
(a) Your Sage install is broken. Where did you get it? Did you
install from sources?
(b) The more entertaining bug: LIB is the same as lib on OSX since
the default filesystem is case aware, but case insensitve. But you can
create a case-sensitive HFS volume on OSX where the above error would
manifest itself. I have complained about LIB being the same as local/
lib and we need to fix that since for the Cygwin port import libs do
have the lib extension and that can cause havoc with the Singular high
level libraries. The Debian port stuffs them somewhere else, too, so
we can easily do the same. This should certainly be done once we
update to the new upstream Singular release when it is out.
If (b) is the case you might be able to fix this by linking LIB to lib
in $SAGE_LOCAL.
> **********************************************************************
>
> and, if i try again, i get the unexpected:
>
> sage: I.groebner_basis()
> verbose 0 (1790: multi_polynomial_ideal.py, groebner_basis) Warning:
> falling back to very slow toy implementation.
> [a, b]
This happens probably because Singular errorored out, but I am not
100% sure and too lazy to look at the code :)
> what's up ? i'm using sage 3.1.4. I'm on os X now, and i haven't done
> a lot of sage since i switched from ubuntu, so perhaps it's just not
> installed properly -- but what could i have done possibly wrong ?
3.1.4 is a little long in the tooth and 3.3 has significant fixes for
Groebner basis in Sage via Singular, so I would recommend you update
to 3.3 once it is out in a couple days.
> thanks !
> pierre
Cheers,
Michael
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