[sage-support] Re: REDUCE in SAGE
John Cremona wrote:
I think it would be impossible to write an interface to a package you
do not (yet) know. Any Sage-REDUCE interface should be written by
someone who knows REDUCE very well. They possibly do not need to know
Sage so well.
John Cremona
I agree with the above. Unfortunately, the intersection of Sage and
REDUCE users is as far as I know empty. Thus Hazem I hope you will
learn REDUCE very well, so you can write a Sage/REDUCE interface.
I made an attempt at this a while ago -- it's in the file
devel/sage/sage/interfaces/reduce.py
included in every copy of Sage. I didn't know reduce at all,
so didn't get so far.
You can try what is there and maye get somewhere...
sage: import sage.interfaces.reduce as r
sage: r.reduce('2+2')
boom?
William
2008/10/13 Hazem [EMAIL PROTECTED]:
Hi William,
I am interested in learning REDUCE by using the Sage interface. I
don't know if it is a requirement to know REDUCE beforehand, or how
well, in order to be able to write the interface. Also, I am a
beginning user of Sage and my Python skills are rudimentary, although
I have a feeling I could pick it up quickly.
Another reason I posted the question was because I have a physicist
friend who asked me if he could use REDUCE and Sage together.
So to answer your question, I would do it if it seemed easy enough for
me :)
With my respects and admiration for your work,
Hazem
On Oct 13, 3:03 am, William Stein [EMAIL PROTECTED] wrote:
Hazem wrote:
Does anyone know how to use the REDUCE algebra package in SAGE? is it
even possible yet?
It is not possible yet. Are you interested in writing a Sage/REDUCE
interface?
William
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[sage-support] Re: [sage-devel] Re: Sage public notebook servers
Jason Grout wrote: William Stein wrote: Hello, A security researcher decided to purposely take down sage.math to demonstrate that it is possible to fork bomb the machine through the public sage notebook servers. I had always plan to run these comletley public servers until something like this happened. Therefore, sagenb.org (and the other public sage notebook servers I host) will be completely disable until further notice. I might re-enable them in the future if I set them up from scratch using a vmware virtual machine and vmware server. Given that I've never successfully configured vmware server on any Linux box, I don't know when this will happen. If a Sage developer would like to attempt to do this instead of me on sage.math please contact me, since this is not currently my highest priority (especially, because I'm in France traveling right now). If this is a final decision, at least for the short term, can we pull the links from the sage website and put some explanatory text up? Yes, this is a shortterm final decision. I always planned to run the public servers as is until some script kiddie $%%#$^% etc. I assume Harald Schilly will fix the website. Note that as I say above, this final decision really is short term, i.e., probably 2-3 weeks. vmware is perfect for this application. William --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: formatting not saved in notebooks
Dear all, I just installed sage 3.1.3.rc0 and the problem about losing the html formatting in notebook cells is still there. Does anyone have an idea how to fix this? Isn't anyone else annoyed by this?? Or am I doing something wrong? Thanks again for your help! Regards, Stan --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: [sage-devel] Re: Sage public notebook servers
I have experience with Xen. Can set up a virtual machine for Sage. It's not that difficult anyway. Serge William Stein wrote: Jason Grout wrote: William Stein wrote: Hello, A security researcher decided to purposely take down sage.math to demonstrate that it is possible to fork bomb the machine through the public sage notebook servers. I had always plan to run these comletley public servers until something like this happened. Therefore, sagenb.org (and the other public sage notebook servers I host) will be completely disable until further notice. I might re-enable them in the future if I set them up from scratch using a vmware virtual machine and vmware server. Given that I've never successfully configured vmware server on any Linux box, I don't know when this will happen. If a Sage developer would like to attempt to do this instead of me on sage.math please contact me, since this is not currently my highest priority (especially, because I'm in France traveling right now). If this is a final decision, at least for the short term, can we pull the links from the sage website and put some explanatory text up? Yes, this is a shortterm final decision. I always planned to run the public servers as is until some script kiddie $%%#$^% etc. I assume Harald Schilly will fix the website. Note that as I say above, this final decision really is short term, i.e., probably 2-3 weeks. vmware is perfect for this application. William --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: solve() problem: raise ValueError, Unable to solve %s for %s%(f, args)
On Sunday 12 October 2008, vpv wrote: Can someone please tell me why it is impossible to solve the following system of boolean equations in SAGE: sage: N=144 sage: P = BooleanPolynomialRing(N,'x',order='lex') sage: t = [] sage: for i in range(0,N): t.append(var(P.gen(i))) sage: print t,t t [x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15, x16, x17, x18, x19, x20, x21, x22, x23, x24, x25, x26, x27, x28, x29, x30, x31, x32, x33, x34, x35, x36, x37, x38, x39, x40, x41, x42, x43, x44, x45, x46, x47, x48, x49, x50, x51, x52, x53, x54, x55, x56, x57, x58, x59, x60, x61, x62, x63, x64, x65, x66, x67, x68, x69, x70, x71, x72, x73, x74, x75, x76, x77, x78, x79, x80, x81, x82, x83, x84, x85, x86, x87, x88, x89, x90, x91, x92, x93, x94, x95, x96, x97, x98, x99, x100, x101, x102, x103, x104, x105, x106, x107, x108, x109, x110, x111, x112, x113, x114, x115, x116, x117, x118, x119, x120, x121, x122, x123, x124, x125, x126, x127, x128, x129, x130, x131, x132, x133, x134, x135, x136, x137, x138, x139, x140, x141, x142, x143] sage: e = [x20 + x15 + 1, x21 + x15 + 1, x28 + x15, x29 + x15, x63 + x31 + x15, x63 + x36, x63 + x37, x63 + x39 + 1, x63 + x44 + 1, x63 + x45 + 1, x63 + x46 + 1, x79 + x47 + 1, x79 + x20 + 1, x79 + x21 + 1, x79 + x28, x79 + x29, x95 + x79 + x31 + 1, x36 + 1, x37 + 1, x95 + x39, x44, x45, x95 + x46, x95 + x47 + x111] sage: e [x20 + x15 + 1, x21 + x15 + 1, x28 + x15, x29 + x15, x63 + x31 + x15, x63 + x36, x63 + x37, x63 + x39 + 1, x63 + x44 + 1, x63 + x45 + 1, x63 + x46 + 1, x79 + x47 + 1, x79 + x20 + 1, x79 + x21 + 1, x79 + x28, x79 + x29, x95 + x79 + x31 + 1, x36 + 1, x37 + 1, x95 + x39, x44, x45, x95 + x46, x95 + x47 + x111] sage: v = [x20, x21, x28, x29, x15, x63, x31, x36, x37, x39, x44, x45, x46, x47, x79, x95, x111] sage: s = solve(e,v) sage-3.1.2/local/lib/python2.5/site-packages/sage/calculus/ equations.py in solve(f, *args, **kwds) 1431 s = m.solve(variables) 1432 except: - 1433 raise ValueError, Unable to solve %s for %s%(f, args) 1434 a = repr(s) 1435 sol_list = string_to_list_of_solutions(a) ValueError: Unable to solve [x20 + x15 + 1, x21 + x15 + 1, x28 + x15, x29 + x15, x63 + x31 + x15, x63 + x36, x63 + x37, x63 + x39 + 1, x63 + x44 + 1, x63 + x45 + 1, x63 + x46 + 1, x79 + x47 + 1, x79 + x20 + 1, x79 + x21 + 1, x79 + x28, x79 + x29, x95 + x79 + x31 + 1, x36 + 1, x37 + 1, x95 + x39, x44, x45, x95 + x46, x95 + x47 + x111] for ([x20, x21, x28, x29, x15, x63, x31, x36, x37, x39, x44, x45, x46, x47, x79, x95, x111],) solve() is aimed at symbolic expressions and not boolean polynomials. Computing a lexicographical Gröbner basis should do the trick. (Maybe solve() should support boolean polynomials, but I'm not sure yet) Cheers, Martin -- name: Martin Albrecht _pgp: http://pgp.mit.edu:11371/pks/lookup?op=getsearch=0x8EF0DC99 _www: http://www.informatik.uni-bremen.de/~malb _jab: [EMAIL PROTECTED] --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Diagonalizing a symbolic matrix
Hi, How can I diagonalize a matrix in the with symbolic values? The matrix has the form of: ((a, b, 0, 0), (b,-a,b,0), (0,b,a,b), (0,0,b,-a)) --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: Diagonalizing a symbolic matrix
On Tuesday 14 October 2008, sonium wrote:
((a, b, 0, 0),
(b,-a,b,0),
(0,b,a,b),
(0,0,b,-a))
Hi, try this:
sage: P.a,b = PolynomialRing(QQ)
sage: matrix(P,4,4,((a, b, 0, 0),
: (b,-a,b,0),
: (0,b,a,b),
: (0,0,b,-a)))
[ a b 0 0]
[ b -a b 0]
[ 0 b a b]
[ 0 0 b -a]
sage: A.echelon_form() # row_reduction by constant entries only
[ a b 0 0]
[ b -a b 0]
[ 0 b a b]
[ 0 0 b -a]
sage: A.echelon_form?
sage: A.echelon_form('frac') # over the fraction field
[1 0 0 0]
[0 1 0 0]
[0 0 1 0]
[0 0 0 1]
sage: A.echelon_form('bareiss') # fraction free
[ b -a 00]
[ 0 a*b b^2-a*b]
[ 0 0-a^2*b - b^3 a^3 + 2*a*b^2]
[ 0 00 -a^4 - 3*a^2*b^2 - b^4]
--
name: Martin Albrecht
_pgp: http://pgp.mit.edu:11371/pks/lookup?op=getsearch=0x8EF0DC99
_www: http://www.informatik.uni-bremen.de/~malb
_jab: [EMAIL PROTECTED]
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[sage-support] Re: parent of Set
On Tue, Oct 14, 2008 at 4:15 AM, Martin [EMAIL PROTECTED] wrote:
Am I doing something wrong in the session below?
I guess so, given the error messages.
I admit that I do not understand python types and methods yet. When
can I apply the functional notation, when the method notation? It
It's not just notation. Python supports both functions and methods,
and they are just completely different things.
seems that it's not a language thing, because they often return
It is a language thing, I think.
different things. As another example, Mod(5,3) and mod(5,3) seem to
agree, while 5.mod(3) is different and 5.Mod(3) is an error.
Is a method responsible for checking whether it's arguments are ofthe
right type/parent, or is there a possibility to restrict the
arguments to a given type/parent?
You should really read the free book Dive into Python. It's great (and free).
Martin
sage: reset()
sage: R=Set(range(0,20,2))
sage: R
{0, 2, 4, 6, 8, 10, 12, 14, 16, 18}
sage: R.type()
---
AttributeErrorTraceback (most recent call
last)
/home/rubey/ipython console in module()
AttributeError: 'Set_object_enumerated' object has no attribute 'type'
sage: R.parent()
---
AttributeErrorTraceback (most recent call
last)
/home/rubey/ipython console in module()
AttributeError: 'Set_object_enumerated' object has no attribute
'parent'
sage: type(R)
class 'sage.sets.set.Set_object_enumerated'
sage: parent(R)
class 'sage.sets.set.Set_object_enumerated'
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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[sage-support] Re: server issues
On Tue, Oct 14, 2008 at 6:36 AM, kcrisman [EMAIL PROTECTED] wrote: kcrisman, This was discussed recently. Several people said that if you start several Sage notebooks on the same machine or virtual machine, but different ports, things can scale up. It's having too many people on the same sage notebook that seems to be the problem. We aren't sure what the bottleneck is; someone needs to do some profiling to find out where it is. I am aware of the thread you are referring to; I am referring to something different, at least I believe so! How much memory do you allocate to the virtual server? Are you sure that all the memory is being used up? My sysadmin says probably 512 MB. That is not enough. Could you allocate, say... 4GB instead? Yes, swap space is completely full and main memory is very close to full. The machine does not halt - you can usually still log in. His point of view is that the current issue is not networking-related, but rather that the various notebooks opening up are creating so many processes that the system is overtaxed. He is probably right. What I am wondering is if anyone knows how quickly a) multiple logins to a notebook might do that or b) interact processes might do that (do the objects get cached, for instance?) or c) people forgetting to log out and perhaps leaving a notebook running might do that c) could easily. Did you set the timeout parameter for the server? timeout -- (default: 0) seconds until idle worksheet sessions automatically timeout, i.e., the corresponding Sage session terminates. 0 means 'never timeout'. Also, you can limit memory usage for individual projects. or d) something else I can't think of might do that. Sysadmin knows about VMs but not so much about internals of Sage, so he isn't sure if it's simply people logging in and then not logging out while the notebook is still active, or if it could be something else. I understand that to some extent there is a lot of uncertainty as to how efficiently the notebook works, but I know so little about how it works (and about interact) that I'm asking the stupid questions, in case one of them turns out to have part of the answer. They are not dumb, and it is very interesting thinking about a concrete example of the notebook being used in a constrained environment. William -- William Stein Associate 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 [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: Diagonalizing a symbolic matrix
Martin Albrecht [EMAIL PROTECTED] writes:
On Tuesday 14 October 2008, sonium wrote:
((a, b, 0, 0),
(b,-a,b,0),
(0,b,a,b),
(0,0,b,-a))
Hi, try this:
sage: A.echelon_form() # row_reduction by constant entries only
sage: A.echelon_form('frac') # over the fraction field
sage: A.echelon_form('bareiss') # fraction free
I thought the original author wanted to find the diagonalised matrix? I.e.,
the eigenvalues on the diagonal. Did I misunderstand?
sage: A= matrix(SR,4,4,((a, b, 0, 0),(b,-a,b,0),(0,b,a,b),(0,0,b,-a)))
sage: A.parent()
Full MatrixSpace of 4 by 4 dense matrices over Symbolic Ring
sage: A.eigenvalues()
[-sqrt(sqrt(5)*b^2 + 3*b^2 + 2*a^2)/sqrt(2),
sqrt(sqrt(5)*b^2 + 3*b^2 + 2*a^2)/sqrt(2),
-sqrt(-sqrt(5)*b^2 + 3*b^2 + 2*a^2)/sqrt(2),
sqrt(-sqrt(5)*b^2 + 3*b^2 + 2*a^2)/sqrt(2)]
sage: A.jordan_form()
[-sqrt(2*x^2 + sqrt(5)*b^2 - 3*b^2)/sqrt(2)|
0| 0|
0]
[--+--+--+--]
[ 0| sqrt(2*x^2 + sqrt(5)*b^2 -
3*b^2)/sqrt(2)| 0|
0]
[--+--+--+--]
[ 0|
0|-sqrt(2*x^2 - sqrt(5)*b^2 - 3*b^2)/sqrt(2)|
0]
[--+--+--+--]
[ 0|
0| 0| sqrt(2*x^2 - sqrt(5)*b^2 -
3*b^2)/sqrt(2)]
Martin
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[sage-support] server issues
kcrisman, This was discussed recently. Several people said that if you start several Sage notebooks on the same machine or virtual machine, but different ports, things can scale up. It's having too many people on the same sage notebook that seems to be the problem. We aren't sure what the bottleneck is; someone needs to do some profiling to find out where it is. I am aware of the thread you are referring to; I am referring to something different, at least I believe so! How much memory do you allocate to the virtual server? Are you sure that all the memory is being used up? My sysadmin says probably 512 MB. Yes, swap space is completely full and main memory is very close to full. The machine does not halt - you can usually still log in. His point of view is that the current issue is not networking-related, but rather that the various notebooks opening up are creating so many processes that the system is overtaxed. What I am wondering is if anyone knows how quickly a) multiple logins to a notebook might do that or b) interact processes might do that (do the objects get cached, for instance?) or c) people forgetting to log out and perhaps leaving a notebook running might do that or d) something else I can't think of might do that. Sysadmin knows about VMs but not so much about internals of Sage, so he isn't sure if it's simply people logging in and then not logging out while the notebook is still active, or if it could be something else. I understand that to some extent there is a lot of uncertainty as to how efficiently the notebook works, but I know so little about how it works (and about interact) that I'm asking the stupid questions, in case one of them turns out to have part of the answer. Thanks, - kcrisman --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: server issues
kcrisman wrote: kcrisman, This was discussed recently. Several people said that if you start several Sage notebooks on the same machine or virtual machine, but different ports, things can scale up. It's having too many people on the same sage notebook that seems to be the problem. We aren't sure what the bottleneck is; someone needs to do some profiling to find out where it is. I am aware of the thread you are referring to; I am referring to something different, at least I believe so! Okay, great. How much memory do you allocate to the virtual server? Are you sure that all the memory is being used up? My sysadmin says probably 512 MB. Yes, swap space is completely full and main memory is very close to full. The machine does not halt - you can usually still log in. His point of view is that the current issue is not networking-related, but rather that the various notebooks opening up are creating so many processes that the system is overtaxed. What I am wondering is if anyone knows how quickly a) multiple logins to a notebook might do that or b) interact processes might do that (do the objects get cached, for instance?) or c) people forgetting to log out and perhaps leaving a notebook running might do that or d) something else I can't think of might do that. Sysadmin knows about VMs but not so much about internals of Sage, so he isn't sure if it's simply people logging in and then not logging out while the notebook is still active, or if it could be something else. There is a timeout parameter for the notebook function that is supposed to automatically kill idle processes, I believe. That might alleviate problems stemming from (c). Jason --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] assume(...) is very slow
Dear all,
Is there a reason why the assume(...) command takes so much longer
than var(...)?
Example:
%time
var('av jbiom lwat p rwat veloc mort epot esv etv esb etb wv wb qbv
bv')
gives:
CPU time: 0.00 s, Wall time: 0.00 s
On the other hand,
%time
assume(p0, veloc0,
mort0,lwat0,jbiom0,rwat0,av0,av1,wv0,wb0,bv0)
gives:
CPU time: 2.91 s, Wall time: 8.78 s
This is with sage 3.1.2. on an Intel Mac with OS X 10.4.11.
Thanks for your help!
Stan
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[sage-support] plot problem with points and contours
I am trying to do a demo for a class and I have encountered a strange
and very annoying error (or I am missing something).
If I do:
{{{
var('x,y')
f = (x^2+y^2)^(.5)
cp = contour_plot(f,(-3,3),(-4,4), fill=False, plot_points = 80, cmap
= 'winter', contours=srange(2.9,3.1,.1))
g = x^2/4+y^2/9-1
gp = implicit_plot(g,(-3,3),(-4,4), plot_points = 80)
pts = point2d([[0,3],[2,0],[-2,0],[0,-3]])
show(cp+gp+pts,figsize = [7*3/4,7])
}}}
then the points with positive coordinates seem misplaced by about 1/10
of a unit; they should be on the ellipse.
-M. Hampton
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[sage-support] Re: plot problem with points and contours
On Tue, Oct 14, 2008 at 8:07 AM, Marshall Hampton [EMAIL PROTECTED] wrote:
I am trying to do a demo for a class and I have encountered a strange
and very annoying error (or I am missing something).
If I do:
{{{
var('x,y')
f = (x^2+y^2)^(.5)
cp = contour_plot(f,(-3,3),(-4,4), fill=False, plot_points = 80, cmap
= 'winter', contours=srange(2.9,3.1,.1))
g = x^2/4+y^2/9-1
gp = implicit_plot(g,(-3,3),(-4,4), plot_points = 80)
pts = point2d([[0,3],[2,0],[-2,0],[0,-3]])
show(cp+gp+pts,figsize = [7*3/4,7])
}}}
then the points with positive coordinates seem misplaced by about 1/10
of a unit; they should be on the ellipse.
-M. Hampton
If you replace 80 by 500 above then everything looks fine.
William
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[sage-support] Re: plot problem with points and contours
It appears this is caused somehow by implicit_plot; if I use
parametric_plot for the ellipse everything works normally.
-M. Hampton
On Oct 14, 10:07 am, Marshall Hampton [EMAIL PROTECTED] wrote:
I am trying to do a demo for a class and I have encountered a strange
and very annoying error (or I am missing something).
If I do:
{{{
var('x,y')
f = (x^2+y^2)^(.5)
cp = contour_plot(f,(-3,3),(-4,4), fill=False, plot_points = 80, cmap
= 'winter', contours=srange(2.9,3.1,.1))
g = x^2/4+y^2/9-1
gp = implicit_plot(g,(-3,3),(-4,4), plot_points = 80)
pts = point2d([[0,3],[2,0],[-2,0],[0,-3]])
show(cp+gp+pts,figsize = [7*3/4,7])}}}
then the points with positive coordinates seem misplaced by about 1/10
of a unit; they should be on the ellipse.
-M. Hampton
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[sage-support] Re: plot problem with points and contours
On Oct 14, 2008, at 08:26 , Jason Grout wrote:
William Stein wrote:
On Tue, Oct 14, 2008 at 8:07 AM, Marshall Hampton [EMAIL PROTECTED]
wrote:
I am trying to do a demo for a class and I have encountered a
strange
and very annoying error (or I am missing something).
If I do:
{{{
var('x,y')
f = (x^2+y^2)^(.5)
cp = contour_plot(f,(-3,3),(-4,4), fill=False, plot_points = 80,
cmap
= 'winter', contours=srange(2.9,3.1,.1))
g = x^2/4+y^2/9-1
gp = implicit_plot(g,(-3,3),(-4,4), plot_points = 80)
pts = point2d([[0,3],[2,0],[-2,0],[0,-3]])
show(cp+gp+pts,figsize = [7*3/4,7])
}}}
then the points with positive coordinates seem misplaced by about
1/10
of a unit; they should be on the ellipse.
-M. Hampton
If you replace 80 by 500 above then everything looks fine.
You took the words right out of my mouth. However, that implicit plot
comes up as a black ellipse for me (3.1.2 and 3.1.3rc0). I don't
think
it should be filled, though, as it should be a plot of x^2/4+y^2/9==1,
not =1. Is anyone else seeing that problem?
I see the Black Blot in 3.1.3.rc0 as well.
Justin
--
Justin C. Walker, Curmudgeon at Large
Institute for the Absorption of Federal Funds
---
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I can't get Jesus on the phone,
But Ol' Milwaukee's Best is my best friend.
---
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[sage-support] Re: plot problem with points and contours
On Tue, Oct 14, 2008 at 9:00 AM, Marshall Hampton [EMAIL PROTECTED] wrote: Ah, right, sorry about that. So the points are in the right place, and the contours were being drawn wrong? That makes me feel much better. Yes. The contours were being drawn to too small of precision, hence not quite in the right spot. William --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: Diagonalizing a symbolic matrix
I thought the original author wanted to find the diagonalised matrix? I.e., the eigenvalues on the diagonal. Did I misunderstand? No, I misunderstood. Sorry for the noise. Cheers, Martin -- name: Martin Albrecht _pgp: http://pgp.mit.edu:11371/pks/lookup?op=getsearch=0x8EF0DC99 _www: http://www.informatik.uni-bremen.de/~malb _jab: [EMAIL PROTECTED] --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: formatting not saved in notebooks
Stan Schymanski wrote: Dear all, I just installed sage 3.1.3.rc0 and the problem about losing the html formatting in notebook cells is still there. Does anyone have an idea how to fix this? Isn't anyone else annoyed by this?? Or am I doing something wrong? Could you post an example worksheet, exactly what things you do to have the problem, what you see, and what you expect to have happen? That would help us nail down exactly what might be the problem. Thanks, Jason --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: plot problem with points and contours
Are you guys implying this is a natural fix? The behavior I see is a
bug, in my opinion. I don't want 500 contours for what I am doing.
Thanks for taking a look!
-M. Hampton
On Oct 14, 9:26 am, Jason Grout [EMAIL PROTECTED] wrote:
William Stein wrote:
On Tue, Oct 14, 2008 at 8:07 AM, Marshall Hampton [EMAIL PROTECTED] wrote:
I am trying to do a demo for a class and I have encountered a strange
and very annoying error (or I am missing something).
If I do:
{{{
var('x,y')
f = (x^2+y^2)^(.5)
cp = contour_plot(f,(-3,3),(-4,4), fill=False, plot_points = 80, cmap
= 'winter', contours=srange(2.9,3.1,.1))
g = x^2/4+y^2/9-1
gp = implicit_plot(g,(-3,3),(-4,4), plot_points = 80)
pts = point2d([[0,3],[2,0],[-2,0],[0,-3]])
show(cp+gp+pts,figsize = [7*3/4,7])
}}}
then the points with positive coordinates seem misplaced by about 1/10
of a unit; they should be on the ellipse.
-M. Hampton
If you replace 80 by 500 above then everything looks fine.
You took the words right out of my mouth. However, that implicit plot
comes up as a black ellipse for me (3.1.2 and 3.1.3rc0). I don't think
it should be filled, though, as it should be a plot of x^2/4+y^2/9==1,
not =1. Is anyone else seeing that problem?
Jason
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[sage-support] Final Sage 3.1.3 sources are out
Hello folks, here are the minimal fixes for the final 3.1.3: #4271: Paul Zimmermann: improve coverage test of ell_generic.py to 100%, and fix typos [Reviewed by John Cremona] #4272: Michael Abshoff: add the files from new coercion to the reference manual [Reviewed by Mike Hansen] #4279: Michael Abshoff: Sage 3.1.3.rc0: numerical noise in rings/ real_lazy.pyx [Reviewed by Mike Hansen] Sources and a sage.math binary are at http://sage.math.washington.edu/home/mabshoff/release-cycles-3.1.3/ The upgrade does not work yet, but hopefully should be done later on tonight. Cheers, Michael --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: assume(...) is very slow
This could be greatly sped up by changing
maxima.assume('...')
to
maxima.eval(assume(..))
in the calculus code...
sage: timeit(maxima.eval('assume(x0)'))
5 loops, best of 3: 53.2 ms per loop
sage: timeit(maxima.assume(x0))
5 loops, best of 3: 122 ms per loop
I don't have time to do this...
On Tue, Oct 14, 2008 at 7:32 AM, Stan Schymanski [EMAIL PROTECTED] wrote:
Dear all,
Is there a reason why the assume(...) command takes so much longer
than var(...)?
Example:
%time
var('av jbiom lwat p rwat veloc mort epot esv etv esb etb wv wb qbv
bv')
gives:
CPU time: 0.00 s, Wall time: 0.00 s
On the other hand,
%time
assume(p0, veloc0,
mort0,lwat0,jbiom0,rwat0,av0,av1,wv0,wb0,bv0)
gives:
CPU time: 2.91 s, Wall time: 8.78 s
This is with sage 3.1.2. on an Intel Mac with OS X 10.4.11.
Thanks for your help!
Stan
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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[sage-support] Re: parent of Set
I believe I understood now: sage: ?parent Type: function snip Return x.parent() if defined, or type(x) if not. I wonder why this is a function, and not a method of Parent? (Am I right that all Sage parents inherit from Parent? Would be great to know this) Set_object inherits from Set_generic, and does not define a parent method, for whatever reason, maybe because the elements of the set need not have a common type. I just saw on http://trac.sagemath.org/sage_trac/attachment/ticket/2314/coerce_2_sets.patch a patch to primes.py, which, in particular, makes Primes inherit from a new class Subset instead of Set_generic. I guess this adresses the issue. It would be wonderful to hear either of yes, correct, or no, you are mistaken. Many thanks, Martin --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: parent of Set
On Oct 14, 2008, at 1:33 PM, Martin Rubey wrote: I believe I understood now: sage: ?parent Type: function snip Return x.parent() if defined, or type(x) if not. I wonder why this is a function, and not a method of Parent? Typically one uses the parent() function when one has an element (such as an integer) and wants it's Parent. This is why it's not an element of the Parent. The docstring should have some better examples, e.g. sage: parent(5) Integer Ring sage: parent(1/2) Rational Field sage: parent(1.5) Real Field with 53 bits of precision (Am I right that all Sage parents inherit from Parent? Would be great to know this) Yes, that is correct. Set_object inherits from Set_generic, and does not define a parent method, for whatever reason, maybe because the elements of the set need not have a common type. I just saw on http://trac.sagemath.org/sage_trac/attachment/ticket/2314/ coerce_2_sets.patch a patch to primes.py, which, in particular, makes Primes inherit from a new class Subset instead of Set_generic. I guess this adresses the issue. It would be wonderful to hear either of yes, correct, or no, you are mistaken. I'm not sure exactly what your question is, but sets don't really have a parent, as the set of all sets is not a category. - Robert --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: REDUCE in SAGE
What is the functionality in REDUCE which you need which is not
already provided in Sage? My impression is that REDUCE is a rather
old package which has not been actively developed for some time
(though I may well be wrong -- I last used it in the 1980s).
John
2008/10/14 Hazem [EMAIL PROTECTED]:
Interesting...there's an opportunity for me to contribute ro Sage.
Very exciting!
I'll have a look at your attempt, William.
In the meantime, can anyone direct me to a comparison between REDUCE
and Mathematica, Maple, MuPAD, Axiom, or Maxima or some of the other
familiar packages? I haven't found anything like that. It will help
provide me with motivation for learning REDUCE. From what i could
gather so far from the REDUCE documentation, it seems quite
impressive, and since there's a free version available for download
(the pay version is relatively affordable), it would be expecially
suited for inclusion as an optional package in Sage (optional
because although there is a free download version, and the full source
is viewable, it is not GPL-free i believe).
Unfortunately, as I have stated in an earlier posting, I work mostly
with numerical analysis and simulation (Matlab/Scilab/LabVIEW), so a
diversion into REDUCE (and Sage, for that matter) will be done on my
free time, and it may take me a while before I am in a position to
write an interface, if ever, so don't wait for me if you feel like
doing it yourself!
regards,
Hazem
On Oct 14, 2:10 am, William Stein [EMAIL PROTECTED] wrote:
John Cremona wrote:
I think it would be impossible to write an interface to a package you
do not (yet) know. Any Sage-REDUCE interface should be written by
someone who knows REDUCE very well. They possibly do not need to know
Sage so well.
John Cremona
I agree with the above. Unfortunately, the intersection of Sage and
REDUCE users is as far as I know empty. Thus Hazem I hope you will
learn REDUCE very well, so you can write a Sage/REDUCE interface.
I made an attempt at this a while ago -- it's in the file
devel/sage/sage/interfaces/reduce.py
included in every copy of Sage. I didn't know reduce at all,
so didn't get so far.
You can try what is there and maye get somewhere...
sage: import sage.interfaces.reduce as r
sage: r.reduce('2+2')
boom?
William
2008/10/13 Hazem [EMAIL PROTECTED]:
Hi William,
I am interested in learning REDUCE by using the Sage interface. I
don't know if it is a requirement to know REDUCE beforehand, or how
well, in order to be able to write the interface. Also, I am a
beginning user of Sage and my Python skills are rudimentary, although
I have a feeling I could pick it up quickly.
Another reason I posted the question was because I have a physicist
friend who asked me if he could use REDUCE and Sage together.
So to answer your question, I would do it if it seemed easy enough for
me :)
With my respects and admiration for your work,
Hazem
On Oct 13, 3:03 am, William Stein [EMAIL PROTECTED] wrote:
Hazem wrote:
Does anyone know how to use the REDUCE algebra package in SAGE? is it
even possible yet?
It is not possible yet. Are you interested in writing a Sage/REDUCE
interface?
William- Hide quoted text -
- Show quoted text -
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[sage-support] Re: parent of Set
William Stein [EMAIL PROTECTED] writes: On Tue, Oct 14, 2008 at 4:15 AM, Martin [EMAIL PROTECTED] wrote: Am I doing something wrong in the session below? I guess so, given the error messages. I admit that I do not understand python types and methods yet. When can I apply the functional notation, when the method notation? It It's not just notation. Python supports both functions and methods, and they are just completely different things. I probably should have asked: why doesn't R after sage: R=Set(range(0,20,2)) have a parent method? I thought that parent is defined by Sage... Maybe differently put: why is the result of Set fundamentally different from, say, the result of vector? (I'm trying to say: fundamentally different with respect to their properties as Python objects) One difference I can see is that vector returns a type, and Set a class, but I couldn't find a definitive answer on the web. http://www.python.org/download/releases/2.2.3/descrintro/ says: Python 2.2 introduces the first phase of type/class unification. This is a series of changes to Python intended to remove most of the differences between built-in types and user-defined classes. but I guess I'm misunderstanding something here, since sage.modules.vector_integer_dense.Vector_integer_dense is certainly not built-in... sage: type(vector([1,2,3])) type 'sage.modules.vector_integer_dense.Vector_integer_dense' sage: type(Set([1,2,3])) class 'sage.sets.set.Set_object_enumerated' Please help! Not sure, whether it's a similar question: why doesn't Primes() export intersect, union, etc. Is this a design decision, a language problem, or just because it's not yet implemented? seems that it's not a language thing, because they often return different things. It is a language thing, I think. It would be great if you could give me a hint. As another example, Mod(5,3) and mod(5,3) seem to agree, while 5.mod(3) is different and 5.Mod(3) is an error. I could not find an answer to that question in Dive into Python, not in the python reference. Are you saying that Integer Ring cannot implement a Mod method, or that it should not? Is a method responsible for checking whether it's arguments are ofthe right type/parent, or is there a possibility to restrict the arguments to a given type/parent? You should really read the free book Dive into Python. It's great (and free). Well, looking at this book, I got the impression that the answer to my question is yes, it's the methods responsibility and no, there is no other possibility. I was hoping for a different answer, but if it's that way, that's OK, too. I'm very sorry if my questions are stupid, but it's really hard for me to grasp the way things work in Sage and Python. Until recently I thought that FriCAS and Sage would be relatively similar, it seems to me now that they are extremely different. I hope I'm only having beginner's troubles. Hoping for your patience, Martin --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: plot problem with points and contours
On Tue, Oct 14, 2008 at 8:42 AM, Marshall Hampton [EMAIL PROTECTED] wrote: Are you guys implying this is a natural fix? The behavior I see is a bug, in my opinion. I don't want 500 contours for what I am doing. 500 is not the number of contours but the *precision*. You have to up it or you won't get what you want. --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: parent of Set
Robert Bradshaw [EMAIL PROTECTED] writes: On Oct 14, 2008, at 1:33 PM, Martin Rubey wrote: I believe I understood now: sage: ?parent Type: function snip Return x.parent() if defined, or type(x) if not. I wonder why this is a function, and not a method of Parent? Typically one uses the parent() function when one has an element (such as an integer) and wants it's Parent. This is why it's not an element of the Parent. Hm, I do not understand that. Why wouldn't one want to use 5.parent(), for example? (The method notation together with tab completion is really nice...) Well, I suppose that some people prefer usual functional notation. The docstring should have some better examples, e.g. sage: parent(5) Integer Ring sage: parent(1/2) Rational Field sage: parent(1.5) Real Field with 53 bits of precision Well, actually, I find the current docstring OK, it answered my question, at least partially. OK, maybe some more examples wouldn't hurt. But what I really do not understand is why Parent doesn't implement a parent method... (Am I right that all Sage parents inherit from Parent? Would be great to know this) Yes, that is correct. OK, great. Set_object inherits from Set_generic, and does not define a parent method, for whatever reason, maybe because the elements of the set need not have a common type. I just saw on http://trac.sagemath.org/sage_trac/attachment/ticket/2314/ coerce_2_sets.patch a patch to primes.py, which, in particular, makes Primes inherit from a new class Subset instead of Set_generic. I guess this adresses the issue. It would be wonderful to hear either of yes, correct, or no, you are mistaken. I'm not sure exactly what your question is, The question was, why does parent(Primes()) give an answer, while Primes().parent() yields an error. but sets don't really have a parent, well, they do: sage: parent(Set([1,2,3])) class 'sage.sets.set.Set_object_enumerated' ;-) I think it's ok to have things without parent, but I do not understand yet, why x.f() and f(x) are designed differently in some cases. One case I stepped into was parent, the other was Mod. as the set of all sets is not a category. Äh? You don't mean category in the mathematical sense here, do you? http://en.wikipedia.org/wiki/Category_of_sets Does Sage have it's own notion of category, just as FriCAS? (since set of all sets doesn't make sense, I guess you mean class of all sets) Martin --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: plot problem with points and contours
William Stein wrote:
On Tue, Oct 14, 2008 at 8:07 AM, Marshall Hampton [EMAIL PROTECTED] wrote:
I am trying to do a demo for a class and I have encountered a strange
and very annoying error (or I am missing something).
If I do:
{{{
var('x,y')
f = (x^2+y^2)^(.5)
cp = contour_plot(f,(-3,3),(-4,4), fill=False, plot_points = 80, cmap
= 'winter', contours=srange(2.9,3.1,.1))
g = x^2/4+y^2/9-1
gp = implicit_plot(g,(-3,3),(-4,4), plot_points = 80)
pts = point2d([[0,3],[2,0],[-2,0],[0,-3]])
show(cp+gp+pts,figsize = [7*3/4,7])
}}}
then the points with positive coordinates seem misplaced by about 1/10
of a unit; they should be on the ellipse.
-M. Hampton
If you replace 80 by 500 above then everything looks fine.
You took the words right out of my mouth. However, that implicit plot
comes up as a black ellipse for me (3.1.2 and 3.1.3rc0). I don't think
it should be filled, though, as it should be a plot of x^2/4+y^2/9==1,
not =1. Is anyone else seeing that problem?
Jason
--~--~-~--~~~---~--~~
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URLs: http://www.sagemath.org
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[sage-support] Re: REDUCE in SAGE
Interesting...there's an opportunity for me to contribute ro Sage.
Very exciting!
I'll have a look at your attempt, William.
In the meantime, can anyone direct me to a comparison between REDUCE
and Mathematica, Maple, MuPAD, Axiom, or Maxima or some of the other
familiar packages? I haven't found anything like that. It will help
provide me with motivation for learning REDUCE. From what i could
gather so far from the REDUCE documentation, it seems quite
impressive, and since there's a free version available for download
(the pay version is relatively affordable), it would be expecially
suited for inclusion as an optional package in Sage (optional
because although there is a free download version, and the full source
is viewable, it is not GPL-free i believe).
Unfortunately, as I have stated in an earlier posting, I work mostly
with numerical analysis and simulation (Matlab/Scilab/LabVIEW), so a
diversion into REDUCE (and Sage, for that matter) will be done on my
free time, and it may take me a while before I am in a position to
write an interface, if ever, so don't wait for me if you feel like
doing it yourself!
regards,
Hazem
On Oct 14, 2:10 am, William Stein [EMAIL PROTECTED] wrote:
John Cremona wrote:
I think it would be impossible to write an interface to a package you
do not (yet) know. Any Sage-REDUCE interface should be written by
someone who knows REDUCE very well. They possibly do not need to know
Sage so well.
John Cremona
I agree with the above. Unfortunately, the intersection of Sage and
REDUCE users is as far as I know empty. Thus Hazem I hope you will
learn REDUCE very well, so you can write a Sage/REDUCE interface.
I made an attempt at this a while ago -- it's in the file
devel/sage/sage/interfaces/reduce.py
included in every copy of Sage. I didn't know reduce at all,
so didn't get so far.
You can try what is there and maye get somewhere...
sage: import sage.interfaces.reduce as r
sage: r.reduce('2+2')
boom?
William
2008/10/13 Hazem [EMAIL PROTECTED]:
Hi William,
I am interested in learning REDUCE by using the Sage interface. I
don't know if it is a requirement to know REDUCE beforehand, or how
well, in order to be able to write the interface. Also, I am a
beginning user of Sage and my Python skills are rudimentary, although
I have a feeling I could pick it up quickly.
Another reason I posted the question was because I have a physicist
friend who asked me if he could use REDUCE and Sage together.
So to answer your question, I would do it if it seemed easy enough for
me :)
With my respects and admiration for your work,
Hazem
On Oct 13, 3:03 am, William Stein [EMAIL PROTECTED] wrote:
Hazem wrote:
Does anyone know how to use the REDUCE algebra package in SAGE? is it
even possible yet?
It is not possible yet. Are you interested in writing a Sage/REDUCE
interface?
William- Hide quoted text -
- Show quoted text -
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-~--~~~~--~~--~--~---
[sage-support] Re: parent of Set
On Oct 14, 2008, at 2:02 PM, Martin Rubey wrote: Robert Bradshaw [EMAIL PROTECTED] writes: On Oct 14, 2008, at 1:33 PM, Martin Rubey wrote: I believe I understood now: sage: ?parent Type: function snip Return x.parent() if defined, or type(x) if not. I wonder why this is a function, and not a method of Parent? Typically one uses the parent() function when one has an element (such as an integer) and wants it's Parent. This is why it's not an element of the Parent. Hm, I do not understand that. Why wouldn't one want to use 5.parent (), for example? (The method notation together with tab completion is really nice...) Well, I suppose that some people prefer usual functional notation. Yes, the method notation + tab completion is very nice and usually prefered. The reason one would want to use parent() however is because not everything has a parent method. For example, int(1).parent () would fail with an attribute error. The parent function always succeeds, giving something reasonable if the object in question doesn't have such a method. Often functional notation is just handier for really common things, e.g. writing sin(pi/5) rather than (pi/5).sin(). The docstring should have some better examples, e.g. sage: parent(5) Integer Ring sage: parent(1/2) Rational Field sage: parent(1.5) Real Field with 53 bits of precision Well, actually, I find the current docstring OK, it answered my question, at least partially. OK, maybe some more examples wouldn't hurt. But what I really do not understand is why Parent doesn't implement a parent method... (Am I right that all Sage parents inherit from Parent? Would be great to know this) Yes, that is correct. OK, great. Set_object inherits from Set_generic, and does not define a parent method, for whatever reason, maybe because the elements of the set need not have a common type. I just saw on http://trac.sagemath.org/sage_trac/attachment/ticket/2314/ coerce_2_sets.patch a patch to primes.py, which, in particular, makes Primes inherit from a new class Subset instead of Set_generic. I guess this adresses the issue. It would be wonderful to hear either of yes, correct, or no, you are mistaken. I'm not sure exactly what your question is, The question was, why does parent(Primes()) give an answer, while Primes().parent() yields an error. but sets don't really have a parent, well, they do: sage: parent(Set([1,2,3])) class 'sage.sets.set.Set_object_enumerated' ;-) I think it's ok to have things without parent, but I do not understand yet, why x.f() and f(x) are designed differently in some cases. One case I stepped into was parent, the other was Mod. Here it's a question of context. The method mod(a,b) is a constructor for an element of Z/mZ, a.mod(b) means divide and take the remainder (as an integer) as the set of all sets is not a category. Äh? You don't mean category in the mathematical sense here, do you? http://en.wikipedia.org/wiki/Category_of_sets Yes, I meant in the sense that the class of all sets can't be an object in a category. I think the confusion here is as to what a parent actually is. A parent is an Object in a concrete category, i.e. it contains Elements. This is why the notion of the parent of a Parent is a bit strange. Because Python (justifiably) doesn't force all objects to have categorically-theoretical underpinnings, we use the type (or, internally the set of all objects of type X) as a pseudo-parent to be able to reason with (e.g. for coercion). Does Sage have it's own notion of category, just as FriCAS? Yes, though it's not as heavily used (yet, it's becoming more so). - Robert --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: plot problem with points and contours
Ah, right, sorry about that. So the points are in the right place, and the contours were being drawn wrong? That makes me feel much better. Thanks again, Marshall On Oct 14, 9:49 am, William Stein [EMAIL PROTECTED] wrote: On Tue, Oct 14, 2008 at 8:42 AM, Marshall Hampton [EMAIL PROTECTED] wrote: Are you guys implying this is a natural fix? The behavior I see is a bug, in my opinion. I don't want 500 contours for what I am doing. 500 is not the number of contours but the *precision*. You have to up it or you won't get what you want. --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: solve() problem: raise ValueError, Unable to solve %s for %s%(f, args)
Hello Martin, Thank you very much for your reply. As you suggested, I computed the lexicographical Gröbner basis of the ideal generated by the polynomials e. It is: G = [x15 + x111 + 1, x20 + x111, x21 + x111, x28 + x111 + 1, x29 + x111 + 1, x31 + x111, x39, x46, x47 + x111, x63 + 1, x79 + x111 + 1, x95, x36 + 1, x37 + 1, x44, x45] How can I now from the expression for G, obtain solutions in the form: x36 == 1 x44 == 0 x46 == 0 ... I'd like to assign the solutions above to the respective variables: x36=1, x44=0,x46=0 so that if I have another equation, say x44 + x2 == 0, this equation will become x2 == 0 after the assignment. Two more questions: in general, is it true that if a Grobner basis exists for a given ideal, then at least one of the equations in the Grobner basis will depend on a single variable (e.g. the equation x37+1==0 in G above depends only on x37)? If yes, does this necessarily mean that the system G (and hence e) is solvable for all variables composing it? Thanks a lot for your help. Regards, vpv P.S. My code for computing G is: N = 144 P = BooleanPolynomialRing(N, 'x',order='lex') x=[] for i in range(0,N): x.append(P.gen(i)) E = [x[20] + x[15] + 1, x[21] + x[15] + 1, x[28] + x[15], x[29] + x[15], x[63] + x[31] + x[15], x[63] + x[36], x[63] + x[37], x[63] + x[39] + 1, x[63] + x[4\ 4] + 1, x[63] + x[45] + 1, x[63] + x[46] + 1, x[79] + x[47] + 1, x[79] + x[20] + 1, x[79] + x[21] + 1, x[79] + x[28], x[79] + x[29], x[95] + x[79] + x[31] +\ 1, x[36] + 1, x[37] + 1, x[95] + x[39], x[44], x[45], x[95] + x[46], x[95] + x[47] + x[111]] I = ideal(E) G=I.groebner_basis() On Oct 14, 10:39 am, Martin Albrecht [EMAIL PROTECTED] wrote: On Sunday 12 October 2008, vpv wrote: Can someone please tell me why it is impossible to solve the following system of boolean equations in SAGE: sage: N=144 sage: P = BooleanPolynomialRing(N,'x',order='lex') sage: t = [] sage: for i in range(0,N): t.append(var(P.gen(i))) sage: print t,t t [x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15, x16, x17, x18, x19, x20, x21, x22, x23, x24, x25, x26, x27, x28, x29, x30, x31, x32, x33, x34, x35, x36, x37, x38, x39, x40, x41, x42, x43, x44, x45, x46, x47, x48, x49, x50, x51, x52, x53, x54, x55, x56, x57, x58, x59, x60, x61, x62, x63, x64, x65, x66, x67, x68, x69, x70, x71, x72, x73, x74, x75, x76, x77, x78, x79, x80, x81, x82, x83, x84, x85, x86, x87, x88, x89, x90, x91, x92, x93, x94, x95, x96, x97, x98, x99, x100, x101, x102, x103, x104, x105, x106, x107, x108, x109, x110, x111, x112, x113, x114, x115, x116, x117, x118, x119, x120, x121, x122, x123, x124, x125, x126, x127, x128, x129, x130, x131, x132, x133, x134, x135, x136, x137, x138, x139, x140, x141, x142, x143] sage: e = [x20 + x15 + 1, x21 + x15 + 1, x28 + x15, x29 + x15, x63 + x31 + x15, x63 + x36, x63 + x37, x63 + x39 + 1, x63 + x44 + 1, x63 + x45 + 1, x63 + x46 + 1, x79 + x47 + 1, x79 + x20 + 1, x79 + x21 + 1, x79 + x28, x79 + x29, x95 + x79 + x31 + 1, x36 + 1, x37 + 1, x95 + x39, x44, x45, x95 + x46, x95 + x47 + x111] sage: e [x20 + x15 + 1, x21 + x15 + 1, x28 + x15, x29 + x15, x63 + x31 + x15, x63 + x36, x63 + x37, x63 + x39 + 1, x63 + x44 + 1, x63 + x45 + 1, x63 + x46 + 1, x79 + x47 + 1, x79 + x20 + 1, x79 + x21 + 1, x79 + x28, x79 + x29, x95 + x79 + x31 + 1, x36 + 1, x37 + 1, x95 + x39, x44, x45, x95 + x46, x95 + x47 + x111] sage: v = [x20, x21, x28, x29, x15, x63, x31, x36, x37, x39, x44, x45, x46, x47, x79, x95, x111] sage: s = solve(e,v) sage-3.1.2/local/lib/python2.5/site-packages/sage/calculus/ equations.py in solve(f, *args, **kwds) 1431 s = m.solve(variables) 1432 except: - 1433 raise ValueError, Unable to solve %s for %s%(f, args) 1434 a = repr(s) 1435 sol_list = string_to_list_of_solutions(a) ValueError: Unable to solve [x20 + x15 + 1, x21 + x15 + 1, x28 + x15, x29 + x15, x63 + x31 + x15, x63 + x36, x63 + x37, x63 + x39 + 1, x63 + x44 + 1, x63 + x45 + 1, x63 + x46 + 1, x79 + x47 + 1, x79 + x20 + 1, x79 + x21 + 1, x79 + x28, x79 + x29, x95 + x79 + x31 + 1, x36 + 1, x37 + 1, x95 + x39, x44, x45, x95 + x46, x95 + x47 + x111] for ([x20, x21, x28, x29, x15, x63, x31, x36, x37, x39, x44, x45, x46, x47, x79, x95, x111],) solve() is aimed at symbolic expressions and not boolean polynomials. Computing a lexicographical Gröbner basis should do the trick. (Maybe solve() should support boolean polynomials, but I'm not sure yet) Cheers, Martin -- name: Martin Albrecht _pgp:http://pgp.mit.edu:11371/pks/lookup?op=getsearch=0x8EF0DC99 _www:http://www.informatik.uni-bremen.de/~malb _jab: [EMAIL PROTECTED] --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For
[sage-support] Re: formatting not saved in notebooks
Sorry, I forgot that there is already a trac ticket on this (#4217). I posted an example on 30 September and it's still in the thread. Basically, a cell like that: %hide %html This is a cell with a long line of text bla bla bla bla bla bla bla... gives a nicely formatted output with line breaks etc. when evaluated. However, if the notebook is closed and re-opened, all the text appears in a single line and with a different format (Courier on my system). The same happens if you evaluate the cell, then click on Edit and then on Save Changes without having done any changes. This gets a bit annoying if you create a longer html text, because you then need to scroll sideways to read the text after re-opening the notebook. Or just evaluate the text cell again, which is a lot easier. :) Thanks for thinking about it. Stan On Oct 14, 11:25 am, Jason Grout [EMAIL PROTECTED] wrote: Could you post an example worksheet, exactly what things you do to have the problem, what you see, and what you expect to have happen? That would help us nail down exactly what might be the problem. Thanks, Jason --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: parent of Set
Robert Bradshaw [EMAIL PROTECTED] writes: Typically one uses the parent() function when one has an element (such as an integer) and wants it's Parent. This is why it's not an element of the Parent. Hm, I do not understand that. Why wouldn't one want to use 5.parent (), for example? (The method notation together with tab completion is really nice...) Well, I suppose that some people prefer usual functional notation. Yes, the method notation + tab completion is very nice and usually prefered. The reason one would want to use parent() however is because not everything has a parent method. For example, int(1).parent () would fail with an attribute error. The parent function always succeeds, giving something reasonable if the object in question doesn't have such a method. Often functional notation is just handier for really common things, e.g. writing sin(pi/5) rather than (pi/5).sin(). Yes, I agree here. Personally I would have done this only for mathematical functions, to reduce confusion. I think it's ok to have things without parent, but I do not understand yet, why x.f() and f(x) are designed differently in some cases. One case I stepped into was parent, the other was Mod. Here it's a question of context. The method mod(a,b) is a constructor for an element of Z/mZ, a.mod(b) means divide and take the remainder (as an integer) Oh, I saw this, but spelling it out made me understand. Thank you! (I'd rather call this method remainder, however, then. Currently it's just very confusing. as the set of all sets is not a category. Äh? You don't mean category in the mathematical sense here, do you? http://en.wikipedia.org/wiki/Category_of_sets Yes, I meant in the sense that the class of all sets can't be an object in a category. Hmm... I think the confusion here is as to what a parent actually is. A parent is an Object in a concrete category, i.e. it contains Elements. Yes, that's why I would have thought that a set should have a parent: the class of all sets. Oh, I see, Set([1,2,3]) is a Parent. This is why the notion of the parent of a Parent is a bit strange. I don't understand, I'd think that it is OK to have a Parent have elements, that are Parents in turn. For example, the set of combinatorial species is a ring (in various ways), but it's very natural to think of a particular species (eg. BinaryTree) as parent of it's structures. Does Sage have it's own notion of category, just as FriCAS? (I should have been more precise: FriCAS has it's own notion of category -- which is *different* from the usual mathematical notion of category. But now I understand that Sage - fortunately - does *not* introduce a concept category, that differs from the usual one.) Martin --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: REDUCE in SAGE
Thanks.
Hazem
On Oct 14, 4:48 pm, David Joyner [EMAIL PROTECTED] wrote:
This should help:http://axiom-wiki.newsynthesis.org/Rosetta
(or you can try here,http://wiki.axiom-developer.org/RosettaStone/
but the download link there is broken). Also, you can
(it says) try reduce here:http://axiom-wiki.newsynthesis.org/FrontPage
I've not tested that though.
On Tue, Oct 14, 2008 at 4:44 PM, Hazem [EMAIL PROTECTED] wrote:
Interesting...there's an opportunity for me to contribute ro Sage.
Very exciting!
I'll have a look at your attempt, William.
In the meantime, can anyone direct me to a comparison between REDUCE
and Mathematica, Maple, MuPAD, Axiom, or Maxima or some of the other
familiar packages? I haven't found anything like that. It will help
provide me with motivation for learning REDUCE. From what i could
gather so far from the REDUCE documentation, it seems quite
impressive, and since there's a free version available for download
(the pay version is relatively affordable), it would be expecially
suited for inclusion as an optional package in Sage (optional
because although there is a free download version, and the full source
is viewable, it is not GPL-free i believe).
Unfortunately, as I have stated in an earlier posting, I work mostly
with numerical analysis and simulation (Matlab/Scilab/LabVIEW), so a
diversion into REDUCE (and Sage, for that matter) will be done on my
free time, and it may take me a while before I am in a position to
write an interface, if ever, so don't wait for me if you feel like
doing it yourself!
regards,
Hazem
On Oct 14, 2:10 am, William Stein [EMAIL PROTECTED] wrote:
John Cremona wrote:
I think it would be impossible to write an interface to a package you
do not (yet) know. Any Sage-REDUCE interface should be written by
someone who knows REDUCE very well. They possibly do not need to know
Sage so well.
John Cremona
I agree with the above. Unfortunately, the intersection of Sage and
REDUCE users is as far as I know empty. Thus Hazem I hope you will
learn REDUCE very well, so you can write a Sage/REDUCE interface.
I made an attempt at this a while ago -- it's in the file
devel/sage/sage/interfaces/reduce.py
included in every copy of Sage. I didn't know reduce at all,
so didn't get so far.
You can try what is there and maye get somewhere...
sage: import sage.interfaces.reduce as r
sage: r.reduce('2+2')
boom?
William
2008/10/13 Hazem [EMAIL PROTECTED]:
Hi William,
I am interested in learning REDUCE by using the Sage interface. I
don't know if it is a requirement to know REDUCE beforehand, or how
well, in order to be able to write the interface. Also, I am a
beginning user of Sage and my Python skills are rudimentary, although
I have a feeling I could pick it up quickly.
Another reason I posted the question was because I have a physicist
friend who asked me if he could use REDUCE and Sage together.
So to answer your question, I would do it if it seemed easy enough for
me :)
With my respects and admiration for your work,
Hazem
On Oct 13, 3:03 am, William Stein [EMAIL PROTECTED] wrote:
Hazem wrote:
Does anyone know how to use the REDUCE algebra package in SAGE? is it
even possible yet?
It is not possible yet. Are you interested in writing a Sage/REDUCE
interface?
William- Hide quoted text -
- Show quoted text -
--~--~-~--~~~---~--~~
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[sage-support] Re: REDUCE in SAGE
John,
I don't know either well enough to be able to answer your question.
CAS for me are mostly a hobby. Occasionally I do need to solve a hard
separation of variables problem, or a hard integral, but usually I
find a workaround, either an approximation or I change something
physical if i can to avoid or to simplify the problem. Aside from work-
related stuff, I like to play with mathematics software and do neat
stuff mostly to help me visualize conceptual things. I tutor my little
cousins and nephews occasionally and it is really nice to be able to
demonstrate a concept in a more concrete way than is usually taught to
them in school.
My impression of REDUCE is that it was better maintained and developed
than Maxima. I think it is still in development and in wide use today,
and it ships the source code as well. It's not GPL free, but the fact
that it has been open-source for a long time means that it has
benefited from many developers and now it's primary developer claims
that it's code is very stable, and it also has a huge collection of
toolboxes. It is also supposed to be very portable. Check it out for
yourself. There are 3 sites worth checking:
http://www.zib.de/Symbolik/reduce
http://www.reduce-algebra.com
http://www.codemist.co.uk/reduce
Hazem
On Oct 14, 4:47 pm, John Cremona [EMAIL PROTECTED] wrote:
What is the functionality in REDUCE which you need which is not
already provided in Sage? My impression is that REDUCE is a rather
old package which has not been actively developed for some time
(though I may well be wrong -- I last used it in the 1980s).
John
2008/10/14 Hazem [EMAIL PROTECTED]:
Interesting...there's an opportunity for me to contribute ro Sage.
Very exciting!
I'll have a look at your attempt, William.
In the meantime, can anyone direct me to a comparison between REDUCE
and Mathematica, Maple, MuPAD, Axiom, or Maxima or some of the other
familiar packages? I haven't found anything like that. It will help
provide me with motivation for learning REDUCE. From what i could
gather so far from the REDUCE documentation, it seems quite
impressive, and since there's a free version available for download
(the pay version is relatively affordable), it would be expecially
suited for inclusion as an optional package in Sage (optional
because although there is a free download version, and the full source
is viewable, it is not GPL-free i believe).
Unfortunately, as I have stated in an earlier posting, I work mostly
with numerical analysis and simulation (Matlab/Scilab/LabVIEW), so a
diversion into REDUCE (and Sage, for that matter) will be done on my
free time, and it may take me a while before I am in a position to
write an interface, if ever, so don't wait for me if you feel like
doing it yourself!
regards,
Hazem
On Oct 14, 2:10 am, William Stein [EMAIL PROTECTED] wrote:
John Cremona wrote:
I think it would be impossible to write an interface to a package you
do not (yet) know. Any Sage-REDUCE interface should be written by
someone who knows REDUCE very well. They possibly do not need to know
Sage so well.
John Cremona
I agree with the above. Unfortunately, the intersection of Sage and
REDUCE users is as far as I know empty. Thus Hazem I hope you will
learn REDUCE very well, so you can write a Sage/REDUCE interface.
I made an attempt at this a while ago -- it's in the file
devel/sage/sage/interfaces/reduce.py
included in every copy of Sage. I didn't know reduce at all,
so didn't get so far.
You can try what is there and maye get somewhere...
sage: import sage.interfaces.reduce as r
sage: r.reduce('2+2')
boom?
William
2008/10/13 Hazem [EMAIL PROTECTED]:
Hi William,
I am interested in learning REDUCE by using the Sage interface. I
don't know if it is a requirement to know REDUCE beforehand, or how
well, in order to be able to write the interface. Also, I am a
beginning user of Sage and my Python skills are rudimentary, although
I have a feeling I could pick it up quickly.
Another reason I posted the question was because I have a physicist
friend who asked me if he could use REDUCE and Sage together.
So to answer your question, I would do it if it seemed easy enough for
me :)
With my respects and admiration for your work,
Hazem
On Oct 13, 3:03 am, William Stein [EMAIL PROTECTED] wrote:
Hazem wrote:
Does anyone know how to use the REDUCE algebra package in SAGE? is it
even possible yet?
It is not possible yet. Are you interested in writing a Sage/REDUCE
interface?
William- Hide quoted text -
- Show quoted text -
--~--~-~--~~~---~--~~
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URLs: http://www.sagemath.org
[sage-support] Re: Sage public notebook servers
I understand the issue. However, is there a way that I can retrieve the worksheets that I have saved in server 2? On Oct 13, 2:29 pm, William Stein [EMAIL PROTECTED] wrote: Hello, A security researcher decided to purposely take down sage.math to demonstrate that it is possible to fork bomb the machine through the public sage notebook servers. I had always plan to run these comletley public servers until something like this happened. Therefore, sagenb.org (and the other public sage notebook servers I host) will be completely disable until further notice. I might re-enable them in the future if I set them up from scratch using a vmware virtual machine and vmware server. Given that I've never successfully configured vmware server on any Linux box, I don't know when this will happen. If a Sage developer would like to attempt to do this instead of me on sage.math please contact me, since this is not currently my highest priority (especially, because I'm in France traveling right now). -- William --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
