juanpool's profile - activity

Finally option 3 did the job.

If I try to install the IPython 0.13 it will not work?

The ipython notebook was released with version 0.12 (see http://ipython.org/ipython-doc/rel-0....), but we ship an older version, 0.10.2 with Sage. There is some progress to upgrading the ipython package in Sage here.

If I run

$ sage -ipython notebook

then the IPython notebook does not start up, instead the following message appears,

Could not open file <notebook> for safe execution.

Is it possible to run an IPython notebook in sage?

Try running

$ sage -sh

from the command-line first. When you then run,

$ f2py -m -c rw2 rw2.f90

it will pick up Sage's copy of f2py (which will use Sage's Python).

I usually run python scripts using SAGE via the command,

sage -python program.py

Now I want to use f2py to use a FORTRAN subroutine in my program. In my Linux version (Ubuntu 12.04) I have installed f2py (version 2), but that version does not use SAGE's Python as I can see from the following. I have a FORTRAN code in rw2.f90 and I run in a linux console,

$f2py -m -c rw2 rw2.f90

and it throws the following message,

error: Command "gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fPIC -I/tmp/tmpyFNYE_/src.linux-x86_64-2.7 -I/usr/lib/python2.7/dist-packages/numpy/core/include -I/usr/include/python2.7 -c /tmp/tmpyFNYE_/src.linux-x86_64-2.7/fortranobject.c -o /tmp/tmpyFNYE_/tmp/tmpyFNYE_/src.linux-x86_64-2.7/fortranobject.o" failed with exit status 1

From the message, it is clear that f2py is trying to use the version of Python that comes with my ubuntu. But I want that f2py to use the SAGE's Python. How I do that?

Best regards

I am considering tree possible solutions.

1. Implementing this algorithm withing a python function.
2. Using the GNU Scientific Library (GSL) from within a SAGE program. More specifically this GSL function.
3. Using R from SAGE with the fBasic R package.

Best Regards.

A stable distribution, defined in wiki is basically defined by,

In probability theory, a random variable is said to be stable (or to have a stable distribution) if it has the property that a linear combination of two independent copies of the variable has the same distribution, up to location and scale parameters.

As far as I know, the family of stable distributions is defined by four parameters: mu, c, alpha and beta. I need to generate random numbers according to a given stable distribution, that is, to a given choice of the parameters of the stable distribution family.

How can it be done in SAGE? Is there some "statistical package" which provides this?

Best regards.

You can simply call the method .networkx_graph():

sage: import networkx as nx
sage: G = graphs.PetersenGraph()             
sage: ng = G.networkx_graph()                
sage: ng
<networkx.classes.graph.Graph object at 0xd3c2f8c>
sage: nx.double_edge_swap(ng)                
1

Incidentally, I didn't know this five minutes ago, so I should tell you how I found out. Lots of functionality for Sage objects lives inside them, in methods. Typically conversion functions are either called ".targettype" or "._targettype_", so I tried

sage: G.netw[HERE I HIT TAB]
      G.networkx_graph

which looked promising. And then typing

sage: G.networkx_graph?

gives the documentation:

       Creates a new NetworkX graph from the Sage graph.

       INPUT:

       * "copy" - if False, and the underlying implementation is a
         NetworkX graph, then the actual object itself is returned.

       EXAMPLES:

          sage: G = graphs.TetrahedralGraph()
          sage: N = G.networkx_graph()
          sage: type(N)
          <class 'networkx.classes.graph.Graph'>

          sage: G = graphs.TetrahedralGraph()
          sage: G = Graph(G, implementation='networkx')
          sage: N = G.networkx_graph()
          sage: G._backend._nxg is N
          False

          sage: G = Graph(graphs.TetrahedralGraph(), implementation='networkx')
          sage: N = G.networkx_graph(copy=False)
          sage: G._backend._nxg is N
          True

PS: Okay, to be perfectly honest, I tried it first and only looked at the documentation when I came to write this. But I would've looked at the documentation if it hadn't worked, I promise! :^)

Thanks very much DSM. That solves my problem. Fool of me. I tried using TAB in sage's notebook, and googled a lot. But I couldn't find it.

I want to use a function of networkx. More specifically I want to use the function

double_edge_swap()

provided in the networkx package included in Sage. For more information see here.

But, I have a Sage graph constructed with:

Graph()

So I want to convert the Sage's Graph() object to a networkx object. How I do that?

Best regards.