[sage-support] pni and Sage 4.7
I am trying to try out SAGE on my Dell Latitude D410 laptop, which has a dual boot system running Vista and Ubuntu [Linux tony-laptop 2.6.32-33-generic #72-Ubuntu SMP Fri Jul 29 21:08:37 UTC 2011 i686 GNU/ Linux]. I downloaded SAGE 4.7 yesterday but the installation process warned that it might not run because of a lack of pni. That seems to be correct: * processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 13 model name : Intel(R) Pentium(R) M processor 2.00GHz stepping: 8 cpu MHz : 2000.000 cache size : 2048 KB fdiv_bug: no hlt_bug : no f00f_bug: no coma_bug: no fpu : yes fpu_exception : yes cpuid level : 2 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov clflush dts acpi mmx fxsr sse sse2 ss tm pbe nx up bts est tm2 bogomips: 3990.16 clflush size: 64 cache_alignment : 64 address sizes : 32 bits physical, 32 bits virtual power management: * The installation process suggested a work-around but warned that it might not work. It didn't! *** tony@tony-laptop:~/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts- i686-Linux$ sh sage -- | Sage Version 4.7.1, Release Date: 2011-08-11 | | Type notebook() for the GUI, and license() for information.| -- /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libcsage.so(print_backtrace+0x3b)[0x27b30e] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libcsage.so(sigdie+0x17)[0x27b34e] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libcsage.so(sage_signal_handler+0x1ad)[0x27ae70] [0x1a1400] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/python2.6/site-packages/sage/rings/ integer.so(initinteger+0x29fb)[0xad750b] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(_PyImport_LoadDynamicModule+0xb6) [0xea83a6] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xe2f78)[0xea5f78] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xe391f)[0xea691f] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xe3c1c)[0xea6c1c] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xe4296)[0xea7296] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(PyImport_ImportModuleLevel+0x3b) [0xea77cb] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xc7916)[0xe8a916] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(PyCFunction_Call+0x128)[0xe30c48] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(PyObject_Call+0x5c)[0xded73c] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(PyObject_CallFunction+0x65) [0xdf0115] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(PyImport_Import+0xb7)[0xea78e7] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/python2.6/site-packages/sage/rings/ complex_double.so(+0xfdf4)[0x4a1df4] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/python2.6/site-packages/sage/rings/ complex_double.so(initcomplex_double+0x18df)[0x4aa91f] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(_PyImport_LoadDynamicModule+0xb6) [0xea83a6] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xe2f78)[0xea5f78] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xe391f)[0xea691f] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xe3c1c)[0xea6c1c] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(+0xe4296)[0xea7296] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686- Linux/local/lib/libpython2.6.so.1.0(PyImport_ImportModuleLevel+0x3b) [0xea77cb] /home/tony/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts-i686-
[sage-support] Obtaining Size of a List and of elements of a List
Dear all, If I have a list, how do I obtain the cardinality of the list, the command Cardinality() doesn't seem to always work. For example, the following code produces a set ComSet of sets of combinations. Rows=3 RowVector=[2,3,2] ComSet=[] for j in range(Columns): C=Combinations(range(Rows),RowVector[j]) ComSet.append(C.list()) show(ComSet) However using Cardinality() on ComSet does not seem to work: ComSet.Cardinality() Basically I am looking for the mathematica command Length. Furthermore how would I be able to map that command on to the elements of ComSet? Many thanks, Vince -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Obtaining Size of a List and of elements of a List
On Fri, Sep 2, 2011 at 3:44 AM, Vince vincent.kni...@gmail.com wrote: Dear all, If I have a list, how do I obtain the cardinality of the list, the command Cardinality() doesn't seem to always work. For example, the following code produces a set ComSet of sets of combinations. Rows=3 RowVector=[2,3,2] ComSet=[] for j in range(Columns): C=Combinations(range(Rows),RowVector[j]) ComSet.append(C.list()) show(ComSet) What's Columns? However using Cardinality() on ComSet does not seem to work: ComSet.Cardinality() Basically I am looking for the mathematica command Length. FYI, most Python and Sage commands start with a lower case. In this case, however, what you're looking for is len(ComSet). If you have an object x, type x-dot-tab to see what methods it supports. Furthermore how would I be able to map that command on to the elements of ComSet? Use list comprehensions (it's a Python thing). sage: L = [[1, 2, 3], [4, 5]] sage: [len(a) for a in L] [3, 2] -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Obtaining Size of a List and of elements of a List
Many thanks for this. Apologies for incomplete code: Columns=3. Vince On 2 Sep 2011 12:01, Robert Bradshaw rober...@math.washington.edu wrote: On Fri, Sep 2, 2011 at 3:44 AM, Vince vincent.kni...@gmail.com wrote: Dear all, If I have a list, how do I obtain the cardinality of the list, the command Cardinality() doesn't seem to always work. For example, the following code produces a set ComSet of sets of combinations. Rows=3 RowVector=[2,3,2] ComSet=[] for j in range(Columns): C=Combinations(range(Rows),RowVector[j]) ComSet.append(C.list()) show(ComSet) What's Columns? However using Cardinality() on ComSet does not seem to work: ComSet.Cardinality() Basically I am looking for the mathematica command Length. FYI, most Python and Sage commands start with a lower case. In this case, however, what you're looking for is len(ComSet). If you have an object x, type x-dot-tab to see what methods it supports. Furthermore how would I be able to map that command on to the elements of ComSet? Use list comprehensions (it's a Python thing). sage: L = [[1, 2, 3], [4, 5]] sage: [len(a) for a in L] [3, 2] -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Obtaining Size of a List and of elements of a List
I'm afraid that's not working. Appartently len has been removed and replaced with cardinality(). Thanks for the tip about .[tab]. However I still seem to be rather stuck: If I run this code: Columns=3 Rows=3 RowVector=[2,3,2] ComSet=[] for j in range(Columns): C=Combinations(range(Rows),RowVector[j]) ComSet.append(C.list()) show(ComSet) ComSet then appears as: [[[0,1],[0,2],[1,2]],[[0,1,2]],[[0,1],[0,2],[1,2]]] which is what I require. If I then use .[tab] on ComSet I get various options, none of which include len and or cardinality. The only option that looks relatively right would be count but I can't seem to find any help on that command and can't seem to use it correctly. If I use .[tab] on any element of ComSet, for example on [[0,1],[0,2],[1,2] ] I seem to get a similar problem (and len does not appear as an option): Defining: C=[[0,1],[0,2],[1,2]] and then C.[tab] gives me the same options as before (i.e. count which I don't seem to be able to find any help for). If however I define C in a different manner: C=Combinations(range(3),2) then C.[tab] does indeed give me cardinality. I am obviously missing something simple. Is there a straightforward way to obtain the length of a set? Any further help would be greatly appreciated, Vince On 2 September 2011 12:01, Robert Bradshaw rober...@math.washington.eduwrote: On Fri, Sep 2, 2011 at 3:44 AM, Vince vincent.kni...@gmail.com wrote: Dear all, If I have a list, how do I obtain the cardinality of the list, the command Cardinality() doesn't seem to always work. For example, the following code produces a set ComSet of sets of combinations. Rows=3 RowVector=[2,3,2] ComSet=[] for j in range(Columns): C=Combinations(range(Rows),RowVector[j]) ComSet.append(C.list()) show(ComSet) What's Columns? However using Cardinality() on ComSet does not seem to work: ComSet.Cardinality() Basically I am looking for the mathematica command Length. FYI, most Python and Sage commands start with a lower case. In this case, however, what you're looking for is len(ComSet). If you have an object x, type x-dot-tab to see what methods it supports. Furthermore how would I be able to map that command on to the elements of ComSet? Use list comprehensions (it's a Python thing). sage: L = [[1, 2, 3], [4, 5]] sage: [len(a) for a in L] [3, 2] -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org -- Dr Vincent Knight Cardiff School of Mathematics Senghennydd Road, Cardiff CF24 4AG (+44) 29 2087 5548 www.vincent-knight.com @drvinceknight http://twitter.com/#!/drvinceknight Skype: drvinceknight -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: integral() error
On Sep 1, 11:19 pm, Justin C. Walker jus...@mac.com wrote:
On Sep 1, 2011, at 19:31 , robin hankin wrote:
Hi.
sage 4.7.1, macosx 10.6.8, firefox 5.0.
When I use the sage notebook the following happens:
var('x')
integral(exp(x),x)
Traceback (click to the left of this block for traceback)
...
RuntimeError: ECL says: THROW: The catch MACSYMA-QUIT is undefined.
What happens if you do
sage: maxima_console()
and what happens with
sage: x.simplify()
(which just sends it to Maxima and back)?
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[sage-support] Re: Labels and others in 3D plots
var('x, y, z');
@interact
def _(a=(-1,1,.1),b=(-1,1,.1),c=(-2,2,.2)):
A1 = implicit_plot3d(z==c,(x,-2.1,2),(y,-2,2),(z,-2,2),
color='red', opacity=0.25, axes=true)
A2 = implicit_plot3d(y==c,(x,-2.1,2),(y,-2,2),(z,-2,2),
color='orange', opacity=0.25, axes=true)
A3 = implicit_plot3d(x==c,(x,-2.1,2),(y,-2,2),(z,-2,2),
color='green', opacity=0.25, axes=true)
S = plot3d(a*x^2-b*y^2,(x,-2,2),(y,-2,2))
def _(which_figure=[A1,A2,A3]):
show(S+which_figure)
You have two different definitions here, but you only call one of them
in the interact, I think - I've never tried this construction, and I'm
not sure it's legit. In any case, even if you created A1 etc., you
couldn't make them options in the second def, because how would they
appear? A1 isn't a string, it's a plot, so I don't know how that
would show up in a dropdown menu.
What about this?
var('x, y, z');
@interact
def
_(a=(-1,1,.1),b=(-1,1,.1),c=(-2,2,.2),which_figure=['1','2','3']):
A1 = implicit_plot3d(z==c,(x,-2.1,2),(y,-2,2),(z,-2,2),
color='red', opacity=0.25, axes=true)
A2 = implicit_plot3d(y==c,(x,-2.1,2),(y,-2,2),(z,-2,2),
color='orange', opacity=0.25, axes=true)
A3 = implicit_plot3d(x==c,(x,-2.1,2),(y,-2,2),(z,-2,2),
color='green', opacity=0.25, axes=true)
S = plot3d(a*x^2-b*y^2,(x,-2,2),(y,-2,2))
show(eval(S+A%s%which_figure))
I'm having trouble with the Jmol and Java plugin in my browser right
now (anyone else having this trouble with 4.7.1 on Safari 5.x?), but
@interact
def _(wh=['1','2']):
A1 = plot(x^2,(x,0,1))
A2 = plot(sqrt(x),(x,0,1))
show(eval(A%s%wh))
works fine, so this should as well, I *think*.
The magic potion here is that we append the formatted string (%s) for
the variable (wh) to A, and then tell Python to evaluate the Python
object you would get if A1 (for instance) were not a string, but an
input to Python.
- kcrisman
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Re: [sage-support] Obtaining Size of a List and of elements of a List
In your code, ComSet is a Python list (not a set) as are many of its components, and you use len(x) to get the size: sage: ComSet, type(ComSet), len(ComSet) ([[[0, 1], [0, 2], [1, 2]], [[0, 1, 2]], [[0, 1], [0, 2], [1, 2]]], type 'list', 3) sage: ComSet[0], type(ComSet[0]), len(ComSet[0]) ([[0, 1], [0, 2], [1, 2]], type 'list', 3) sage: ComSet[0][0], type(ComSet[0][0]), len(ComSet[0][0]) ([0, 1], type 'list', 2) sage: ComSet[0][0][0], type(ComSet[0][0][0]) (0, type 'int') cardinality is a method not of Python lists, but of the Combinations object. For example: sage: C Combinations of [0, 1, 2] of length 2 sage: C.cardinality() 3 sage: list(C) [[0, 1], [0, 2], [1, 2]] sage: C.list() [[0, 1], [0, 2], [1, 2]] sage: len(C.list()) 3 The reason tab-completion doesn't reveal len is because len is a function, not a method on the object, and the dot-tab procedure returns the object's contents. (Admittedly, if you type ComSet.__[tab], you can see the special methods, including ComSet.__len__ which is used behind the scenes, but you would never write ComSet.__len__() in real code.) Does that help? Doug -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: Bug in Graph.is_chordal
Hi Nathann, after this line (line 9520 in http://trac.sagemath.org/sage_trac/attachment/ticket/11735/trac_11735.patch): g.delete_vertices([vv for vv in g.neighbors(v) if vv != y and vv != x]) How can one be sure that x and y are still connected? (otherwise no path x -- y exists) I don't know whether this holds for the current code. In the paper another method of choosing v,x,y is described, and the authors prove that x,y stay connected. For the patch, I'm not familiar with the version control system used and unfortunately I don't have time to learn it now. Regards, Jan On Sep 1, 6:23 pm, Nathann Cohen nathann.co...@gmail.com wrote: Hello ! I'm finally back to the civilisation if you want us to deal with this patch :-) Nathann On 29 August 2011 15:46, Nathann Cohen nathann.co...@gmail.com wrote: Hello Jan !!! I am sorry for my vry slow answers, I am on vacation right now, with very very bad WiFi connections when I get some. If you think you would sleep better with copying the implementation given in the paper, then the best is probably to write a patch for this. I like mine better, just because I feel like I understand how it works, but to be honest I do not really mind in this case as it is so easy to check whether the code is correct. What would you think of writing a patch to change the current behaviour to match the paper using your code, while letting my version of it (the updated/fixed one) in the code as a comment ? Before returning the result, it should be checked, for instance like I did in my patch. If at some point the value returned is incorrect, the exception should be There was an error in the computed answer... Please report the bug or something alike so that we quickly learn of it and fix the mistake. What do you think ? What I fear the most are silent mistakes.. The ones you do not notice. In these situations I don't mind Sage answering me that it wasn't able to do the computations, especially when the patch is already written :-) If you have time to create the patch, I will try to review it as soon as I get back to the civilisation (possibly next friday). Otherwise we'll talk about it then :-) Thank you for your work, by the way ! Nathann -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: pni and Sage 4.7
From the location of your sage install ~/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts- i686-Linux I see you downloaded a prebuild binairy, I guess what's going wrong is that this binary was compiled in such a way that it's not compatible with your system. This post https://groups.google.com/forum/#!topic/sage-support/XJS-3u5z7ws might be of help. I don't know if we have old prebuild binary's publically available somewhere, but at least we have old source code on http://www.sagemath.org/src-old/ -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Re: pni and Sage 4.7
On Fri, Sep 2, 2011 at 10:00 AM, Maarten Derickx m.derickx.stud...@gmail.com wrote: From the location of your sage install ~/Documents/sage-4.7.1-linux-32bit-ubuntu_10.04_lts- i686-Linux I see you downloaded a prebuild binairy, I guess what's going wrong is that this binary was compiled in such a way that it's not compatible with your system. This post https://groups.google.com/forum/#!topic/sage-support/XJS-3u5z7ws might be of help. I don't know if we have old prebuild binary's publically available somewhere, That won't help. but at least we have old source code on http://www.sagemath.org/src-old/ And current source code: http://www.sagemath.org/download-source.html -- William -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org -- William Stein Professor of Mathematics University of Washington http://wstein.org -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Re: Bug in Graph.is_chordal
Hellooo Jan !
It is 20:20, it is almost dark outside and I am getting home by bike.
Worst of all, I am being assaulted by hungry mosquitoes. I re-read it
the following enough times to be sure that if I miswrote v instead
of x somewhere, reading it again wouldn't have changed anything.
When v is considered for removal, it is a leaf of the lex-BFS tree.
Its father (and first discoverer) is named x, and we suppose that
there is a vertex y which is not a neighbor of x, otherwise v is
removed without any problem.
Why should there be a x-y path avoiding all of v's neighbors ? Well,
first note that v is the furthest vertex from the source. Not
strictly, of course, but a lex-BFS is a BFS, and as we are testing for
removal the vertices in the reverse of the discovery order, it means
that in the lex-BFS exploration the vertex v is the last one to be
discovered (without considering the vertices that have been deleted
since the beginning of the elimination algorithm). Hence, it is the
one which is the further away from the source, even if other vertices
may be at equal distance from the source.
Now, how can v be adjacent to the other vertices of the graph ? Well,
for instance v can not be connected to any of x's ancestors, as its
distance from the source is strictly greater than the distance between
x and the source. Hence there is a path from x to the source of the
lex-BFS which does not touch any of x's neighbors. By the same reason,
the vertex y can not be closer than v from the source. If it were,
there would be a path from y to the source (from ancestor to ancestor)
which would avoid all of v's neighbors.
Hence, at some point, when the lex-BFS algorithm was processing all
the vertices at distance d(source, y) = d(source, v), it picked y
before v (we are removing the vertices in reverse order). But then, we
know that y and v have different sets of neighbors among the vertices
at distance d(source, { v or y} ) - 1 from the source. We know that
because by assumption y is not adjacent to x. In this case, because y
was picked before v in the lex-BFS ordering, it means that the lex-BFS
code of y at this moment was strictly greater than the lex-BFS code of
v.
Hence there is a neighbor of y at distance d(source, y) - 1 which is
not a neighbor of v. Hence there is a path from y to the source going
through this vertex which avoids all of v's neighbors, hence
connectedness, hence certificate, hence I can jump on my bike to
escape the mosquitoes.
Nathann
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[sage-support] How make typesetting be the default in all notebooks?
How make typesetting be the default in all notebooks? (i.e. I don't want users to have to check the Typeset checkbox all the time.) Sincerely, Chris Seberino P.S. I tried googling for it but could not find the answer. -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: Bug in Graph.is_chordal
Hi Nathann,
First, thank you for taking time to give a very detailed reply.
I'm sorry but I'm not yet done bothering you :-]
I think this is wrong:
When v is considered for removal, it is a leaf of the lex-BFS tree.
Its father (and first discoverer) is named x, and we suppose that
there is a vertex y which is not a neighbor of x, otherwise v is
removed without any problem.
(I also mentioned this in message #3, but it seems it still holds)
Consider: g = graph({1:[2,3,4,5],2:[3,5],4:[3,5]}).
g is like [the 4-cycle 2--3--4--5] + [(1,x) for x in [2 .. 5]]
g is not chordal.
A LexBFS ordering (reverse elimination ordering) could be [1, 2, 3, 5,
4].
Notice that all v in [2 .. 5] have father equal to 1.
But then x is adjacent to every other vertex, i.e. we can't find y.
Regards,
Jan
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Re: [sage-support] Obtaining Size of a List and of elements of a List
Thanks, This really has clarified everything :) Much appreciated, Vince On 2 Sep 2011 14:49, D. S. McNeil dsm...@gmail.com wrote: In your code, ComSet is a Python list (not a set) as are many of its components, and you use len(x) to get the size: sage: ComSet, type(ComSet), len(ComSet) ([[[0, 1], [0, 2], [1, 2]], [[0, 1, 2]], [[0, 1], [0, 2], [1, 2]]], type 'list', 3) sage: ComSet[0], type(ComSet[0]), len(ComSet[0]) ([[0, 1], [0, 2], [1, 2]], type 'list', 3) sage: ComSet[0][0], type(ComSet[0][0]), len(ComSet[0][0]) ([0, 1], type 'list', 2) sage: ComSet[0][0][0], type(ComSet[0][0][0]) (0, type 'int') cardinality is a method not of Python lists, but of the Combinations object. For example: sage: C Combinations of [0, 1, 2] of length 2 sage: C.cardinality() 3 sage: list(C) [[0, 1], [0, 2], [1, 2]] sage: C.list() [[0, 1], [0, 2], [1, 2]] sage: len(C.list()) 3 The reason tab-completion doesn't reveal len is because len is a function, not a method on the object, and the dot-tab procedure returns the object's contents. (Admittedly, if you type ComSet.__[tab], you can see the special methods, including ComSet.__len__ which is used behind the scenes, but you would never write ComSet.__len__() in real code.) Does that help? Doug -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] How make typesetting be the default in all notebooks?
Hi, Unfortunately, I don't think there is support for this feature at present. If there were, it would likely be implemented via the Settings link in the notebook for a given user. On Fri, Sep 2, 2011 at 11:49 AM, Chris Seberino cseber...@gmail.com wrote: How make typesetting be the default in all notebooks? (i.e. I don't want users to have to check the Typeset checkbox all the time.) Sincerely, Chris Seberino P.S. I tried googling for it but could not find the answer. -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org -- William Stein Professor of Mathematics University of Washington http://wstein.org -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: How make typesetting be the default in all notebooks?
On Sep 2, 3:20 pm, William Stein wst...@gmail.com wrote: Unfortunately, I don't think there is support for this feature at present. If there were, it would likely be implemented via the Settings link in the notebook for a given user. Just to make sure we are talking about the same thing So there is nothing I can add to init.sage that is equivalent to clicking the Typeset checkbox in a worksheet? Sincerely, Chris -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Re: Bug in Graph.is_chordal
Consider: g = graph({1:[2,3,4,5],2:[3,5],4:[3,5]}).
Hahahahhahaaha ! Dead right :-)
And the code works anyway because the tree it returns actually is *NOT* a
BFS tree :-)
sage: g.lex_BFS(tree = True)[1].edges()
[(2, 1, None), (3, 2, None), (4, 5, None), (5, 2, None)]
Two (obvious) black patches in my previous proof :
* It totally ignores the edges between classes of vertices with the same
distance to the source -- precisely what your counter-example destroys.
* without considering the last neighbor of v discovered before v itself,
its process does not ensure that the neighborhood of a removed vertex is
indeed simplicial. Very bad indeed :-)
For a time I thought I would be able to patch my proof, but in the end I
don't get how this recognition algorithm works... Which is a pity because I
am sure I had found a clear explanation in a paper when I implemented all
that stuff. What I need right now is some sleep though. Sounds like this
will really require a patch :-)
Thank you for your perseverance ! At the least I enjoyed the time thinking
of this algorithm again and (re ?)-learned a few nice tricks ;-)
Good night !
Nathann
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[sage-support] Re: How make typesetting be the default in all notebooks?
On 9/2/11 3:51 PM, Chris Seberino wrote: On Sep 2, 3:20 pm, William Steinwst...@gmail.com wrote: Unfortunately, I don't think there is support for this feature at present. If there were, it would likely be implemented via the Settings link in the notebook for a given user. Just to make sure we are talking about the same thing So there is nothing I can add to init.sage that is equivalent to clicking the Typeset checkbox in a worksheet? When you click Help in the notebook, searching the page for Typeset leads to this: Type pretty_print_default() in an input cell and press shift-enter. All future output will be typeset automatically. Can you try to put pretty_print_default() in the init.sage and see if that works? Thanks, Jason -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: How make typesetting be the default in all notebooks?
On Sep 2, 6:49 pm, Jason Grout jason-s...@creativetrax.com wrote: Type pretty_print_default() in an input cell and press shift-enter. All future output will be typeset automatically. Can you try to put pretty_print_default() in the init.sage and see if that works? Jason Thankfully that works great. There is one potential tiny bug fyi I found If you alter typsetting with pretty_print_default, then it works fine but it does not magically add/remove the check in the checkbox of the worksheet. In other words, adding prety_print_default() to init.sage works but the worksheet still shows an unchecked Typeset box in a new worksheet which may confuse some users. I suppose a fix would require pretty_print_default invocations triggering some javascript code to add/remove the check? I don't know. Sincerely, Chris -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] noob q: working directory
Hi everybody.
In the tutorial:
Alternatively, evaluating c.save('filename.png')
will save the plot to the given file.
I tried it, then searched my disk for the relevant filename
with no result. Is it a bug? What directory ought it to be in?
If I try to read in a file, what is the base directory?
...
Also: ARGH. Google Groups won't let me register with my preferred
address (bro...@pobox.com).
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