Using QEPCAD in sagenb and/or sagecell

[fbotana]

Hi,

yesterday I posted a question regarding QEPCAD uses under Sage. Since it seems that I did not explain the issue, I'm trying again:

I would like to use QEPCAD in sagecell: Sending

var('a,b,c,d,x,y,z')
qf = qepcad_formula
ellipse = 3*x^2 + 2*x*y + y^2 - x + y - 7
F = qf.exists(y, ellipse == 0)
qepcad(F)

to sagecell I get an error:

OSError: [Errno 13] Permission denied: '/home/sageserver/sage/local/share/sage/ext/QEPCAD/'

The sagecell permalink: http://sagecell.sagemath.org/?q=cxpnrv

A similar thing happens with sagenb server: 
...
RuntimeError: Unable to start QEPCAD

AFAIK qepcad is the only software under Sage able to solve semialgebraic systems. Enabling QEPCAD would be welcome!

Thank you.

[Jason Grout]

On 10/10/13 1:44 PM, fbotana wrote:
> Hi,
>
> yesterday I posted a question

> <http://groups.google.com/group/sage-support/t/b388b6c45a7d535f>

> regarding QEPCAD uses under Sage. Since it seems that I did not explain
> the issue, I'm trying again:
>
> I would like to use QEPCAD in sagecell: Sending
>
> var('a,b,c,d,x,y,z')
> qf = qepcad_formula
> ellipse = 3*x^2 + 2*x*y + y^2 - x + y - 7
> F = qf.exists(y, ellipse == 0)
> qepcad(F)
>
> to sagecell I get an error:
>
> OSError: [Errno 13] Permission denied: '/home/sageserver/sage/local/share/sage/ext/QEPCAD/'
>

Right now, qepcad is not installed on the sage cell server. I'm trying
to install it now.

Jason

[Jason Grout]

It worked! I'm in the process of rolling out the update. Give it maybe
1/2 hour or so.

Jason

[William Stein]

Just curious... which version of Sage did you use, and did you install
it by doing anything other than

sage -i qepcad

I just tried the above with both sage-5.12 and sage-5.11 on
cloud.sagemath (so ubuntu 12.04 LTS), and the build fails with:

g++: error: /usr/local/sage/sage-5.12/spkg/build/qepcad-1.50/src/saclib2.2.0/lib/saclibo.a:
No such file or directory
g++: error: /usr/local/sage/sage-5.12/spkg/build/qepcad-1.50/src/saclib2.2.0/lib/saclibo.a:
No such file or directory
make[1]: *** [opt] Error 1

>
>
> Jason
>
>
>
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--
William Stein
Professor of Mathematics
University of Washington
http://wstein.org

[Jason Grout]

On 10/10/13 3:19 PM, William Stein wrote:
> Just curious... which version of Sage did you use, and did you install
> it by doing anything other than
>
> sage -i qepcad
>

That's it. It's on CentOS 6.4.

> I just tried the above with both sage-5.12 and sage-5.11 on
> cloud.sagemath (so ubuntu 12.04 LTS), and the build fails with:

I know. That's why I was surprised. QEPCad isn't installed on
sagenb.org for the same reason.

I'm still getting errors when the sage worker process tries to execute
qepcad (likely a permission issue of some sort---it's hard to tell since
qepcad just core dumps when I try to run it), but I can execute it as
the sage server user just fine.

Thanks,

Jason

[Jason Grout]

On 10/10/13 2:09 PM, Jason Grout wrote:
> It worked! I'm in the process of rolling out the update. Give it maybe
> 1/2 hour or so.

It works now:

http://sagecell.sagemath.org/?q=xlgebu

Jason