[sage-support] Re: How to detect memory leaks?
Dear Robert, On 24 Okt., 06:46, Robert Bradshaw [EMAIL PROTECTED] wrote: Well, memory leaks are always possible, but this should be safe (i.e. if there's a bug, it's in Cython). Can you post what your class definition is? It is the Toy-F5 that I implemented at Sage Days 10. See http://sage.math.washington.edu/home/SimonKing/f5/f5.pyx Are you running this from the command line? Yes. The example is: sage: attach f5.pyx Compiling /home/SimonKing/f5/f5.pyx... sage: from sage.rings.ideal import Cyclic sage: R=PolynomialRing(QQ,'x',5) sage: I=Cyclic(R) sage: F=F5() sage: time G1=F(I) # removing some protocol output CPU times: user 0.30 s, sys: 0.02 s, total: 0.32 s Wall time: 0.32 s sage: G1==I.groebner_basis() True sage: del F sage: get_memory_usage() 423.21484375 sage: for i in range(100): F=F5() G1=F(I) del F # removing protocol output sage: get_memory_usage() 681.00390625 sage: (_-423.21484375)/100 2.5778906250 try doing the whole operation in a function body and see if the results are the same. sage: def f(n): for i in range(n): F=F5() G1=F(I) sage: f(100) # removing protocol sage: get_memory_usage() 938.33984375 sage: (_-681.00390625)/100 2.5733593750 So, that's about the same. I wonder one thing: Could the ~2.58 MB come from the protocol that my function prints? Cheers Simon --~--~-~--~~~---~--~~ 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: accessing a notebook on a remote machine
Dear William and Jason, I got the network socket fixed by our support, went to http://www.whatismyip.com/ to find out my IP address, then followed William's instructions and typed: sage: notebook(address=ipaddress,port=8100,secure=True) where ipaddress was replaced by the IP address of my computer. Then, I was able to connect to the running notebook from another computer on the network just by typing https://ipaddress:8100 (again with ipaddress replaced by the IP address of the computer running the notebook). When I try to connect to this notebook in the same way from a computer that is not on the same network, I get a network timeout, which reassures me that the notebook is not going to be a gateway for hackers around the world to create havoc on my computer. I will now play around with adding users etc. as described in William's post above. Too easy! Thanks for your help! All the best, Stan On Oct 23, 5:09 pm, William Stein [EMAIL PROTECTED] wrote: On Thu, Oct 23, 2008 at 8:02 AM, Stan Schymanski [EMAIL PROTECTED] wrote: Hi Jason, Thanks for the quick reply. Sorry I didn't provide any information. I'm running sage 3.1.4 directly on a MacBook Pro under OS X 10.4.11, and I do have a computer name that should be accessible from other computers. I did activate the Remote Login in the System preferences, but if I do ssh [EMAIL PROTECTED] or ssh [EMAIL PROTECTED] from another computer, the operation times out. Would this work if a notebook server was running on the machine, or do I have to sort out the right way to connect first? Have you tried something like the following. Startup sage on your macbook pro and type sage: notebook(address=ipaddress,port=8100,secure=True) then from another computer on your network try to visit the web page https://ipaddress:8100 That's pretty much it, except for making accounts. To create accounts you could temporarily do sage: notebook(address=ipaddress,port=8100,secure=True, accounts=True) let people make accounts, then do sage: notebook(address=ipaddress,port=8100,secure=True,accounts=False) so no new accounts can be created. 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: code generation
On Oct 24, 2008, at 5:28 AM, peter wrote: OK, sorry, I explain a little bit more in detail: - I work on thermal building simulation. We use for example one environment (TRNSYS) where you can connect models (for example building model to heating system model etc.). The models are mainly written in Fortran or C++ and compiled in DLL's that are then called by the equation solver. Our goal is to write the models not in C+++ or fortran anymore, but either in Matlab (and or Simulink), Scilab or Sage. So in clear, I want to profit of one of these mathematical environments, write models there and use them later in our simulation program. One thing you can do is prototype in Sage and python, make use of profiling tools and then re-write the computation intensive portions using Cython or Pysco. At the moment, there really aren't tools to generate C++ or Fortran code from the Sage code. However, the latter tools are close to Python in syntax and can work with Sage. That said, I'm fairly certain that it wouldn't be very difficult to write a code generator for Sage. If one can get the underlying structure of each of the expressions, it shouldn't be very difficult to convert that to C++ or Fortran as long as the expressions can be represented in the language without additional code. This is the approach that most the code generators I've seen use. Maxima has GENTRAN if someone is interested in seeing how one works and I know there is(are) paper(s) that discuss it. The main problem is that someone doing this would need to be fairly familiar with Sage internals. Cheers, Tim. --- Tim Lahey PhD Candidate, Systems Design Engineering University of Waterloo smime.p7s Description: S/MIME cryptographic signature
[sage-support] Re: code generation
OK, sorry, I explain a little bit more in detail: - I work on thermal building simulation. We use for example one environment (TRNSYS) where you can connect models (for example building model to heating system model etc.). The models are mainly written in Fortran or C++ and compiled in DLL's that are then called by the equation solver. Our goal is to write the models not in C+++ or fortran anymore, but either in Matlab (and or Simulink), Scilab or Sage. So in clear, I want to profit of one of these mathematical environments, write models there and use them later in our simulation program. --~--~-~--~~~---~--~~ 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: code generation
pypy has some power in this direction http://www.strakt.com/~jacob/Pypy_for_the_rest_of_us.pdf http://morepypy.blogspot.com/ On Fri, Oct 24, 2008 at 12:38 PM, Tim Lahey [EMAIL PROTECTED] wrote: On Oct 24, 2008, at 5:28 AM, peter wrote: OK, sorry, I explain a little bit more in detail: - I work on thermal building simulation. We use for example one environment (TRNSYS) where you can connect models (for example building model to heating system model etc.). The models are mainly written in Fortran or C++ and compiled in DLL's that are then called by the equation solver. Our goal is to write the models not in C+++ or fortran anymore, but either in Matlab (and or Simulink), Scilab or Sage. So in clear, I want to profit of one of these mathematical environments, write models there and use them later in our simulation program. One thing you can do is prototype in Sage and python, make use of profiling tools and then re-write the computation intensive portions using Cython or Pysco. At the moment, there really aren't tools to generate C++ or Fortran code from the Sage code. However, the latter tools are close to Python in syntax and can work with Sage. That said, I'm fairly certain that it wouldn't be very difficult to write a code generator for Sage. If one can get the underlying structure of each of the expressions, it shouldn't be very difficult to convert that to C++ or Fortran as long as the expressions can be represented in the language without additional code. This is the approach that most the code generators I've seen use. Maxima has GENTRAN if someone is interested in seeing how one works and I know there is(are) paper(s) that discuss it. The main problem is that someone doing this would need to be fairly familiar with Sage internals. Cheers, Tim. --- Tim Lahey PhD Candidate, Systems Design Engineering University of Waterloo -- Jurgis Pralgauskis tel: 8-616 77613; jabber: [EMAIL PROTECTED]; skype: dz0rdzas; Don't worry, be happy and make things better ;) --~--~-~--~~~---~--~~ 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] Problems with .show() and integration
Here's the code:
sigma = 0.2
gauss(x) = exp(-(x)2/(2*sigma2))
gauss1 = gauss(x).derivative
gauss2 = gauss1(x).derivative
ngauss2(x) = -1*gauss2(x)
sngauss2(x,y) = ngauss2(sqrt(x2 + y2))
a1 = var('a1'); a2 = var('a2'); b1 = var('b1'); b2 = var('b2')
chunkx = integral(sngauss2, x, a1, b1)
chunky = integral(chunkx, y, a2, b2)
chunky.show()
When evaluated it says It looks like jsMath failed to set up properly
(error code -7). I will try to keep going, but it could get ugly.
Calling print chunky prints something weird.
All i want to do is to get symbolic formula for an integral of part of
a surface, described by sngauss2, so i can use it outside of Sage.
--~--~-~--~~~---~--~~
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: code generation
On Friday 24 October 2008 11:28:05 peter wrote: OK, sorry, I explain a little bit more in detail: - I work on thermal building simulation. We use for example one environment (TRNSYS) where you can connect models (for example building model to heating system model etc.). The models are mainly written in Fortran or C++ and compiled in DLL's that are then called by the equation solver. Our goal is to write the models not in C+++ or fortran anymore, but either in Matlab (and or Simulink), Scilab or Sage. So in clear, I want to profit of one of these mathematical environments, write models there and use them later in our simulation program. It is possible to call any python code from c/c++ as described here: http://docs.python.org/extending/index.html but cython makes this much easier. You can write cython functions which convert the C data types passed to them to the appropriate sage types, and call your implementation in Sage. Then you can call these cython functions by defining them to be public: http://docs.cython.org/docs/external_C_code.html#public-declarations Cheers, Burcin --~--~-~--~~~---~--~~ 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: Problems with .show() and integration
LRN wrote:
Here's the code:
sigma = 0.2
gauss(x) = exp(-(x)2/(2*sigma2))
gauss1 = gauss(x).derivative
gauss2 = gauss1(x).derivative
ngauss2(x) = -1*gauss2(x)
sngauss2(x,y) = ngauss2(sqrt(x2 + y2))
a1 = var('a1'); a2 = var('a2'); b1 = var('b1'); b2 = var('b2')
chunkx = integral(sngauss2, x, a1, b1)
chunky = integral(chunkx, y, a2, b2)
chunky.show()
When evaluated it says It looks like jsMath failed to set up properly
(error code -7). I will try to keep going, but it could get ugly.
This is a problem with fonts, not with any math. To get the nice TeX
display with jsMath, please download a set of fonts from here:
http://www.math.union.edu/~dpvc/jsMath/download/jsMath-fonts.html
If you are on Unix, ignore the instructions on the page and just unzip
the fonts into your ~/.fonts directory.
Please let us know if that solves the problem.
We *really* ought to fix this to behave nicer (i.e., instead of just
giving an error, just offer to give the fonts to the user and give them
instructions for installing them). Of course, I've said this before,
but not done anything about it!
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: accessing a notebook on a remote machine
Stan Schymanski wrote: Dear William and Jason, I got the network socket fixed by our support, went to http://www.whatismyip.com/ to find out my IP address, then followed William's instructions and typed: sage: notebook(address=ipaddress,port=8100,secure=True) where ipaddress was replaced by the IP address of my computer. Then, I was able to connect to the running notebook from another computer on the network just by typing https://ipaddress:8100 (again with ipaddress replaced by the IP address of the computer running the notebook). When I try to connect to this notebook in the same way from a computer that is not on the same network, I get a network timeout, which reassures me that the notebook is not going to be a gateway for hackers around the world to create havoc on my computer. I will now play around with adding users etc. as described in William's post above. Too easy! Thanks for your help! You should also be able to do: notebook(address=computername, port=8100, secure=True) to be able to address it as just https://computername:8100. That might work anyway even with address='ipaddress' too. 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: Problems with .show() and integration
Is gauss(x) = exp(-(x)2/(2*sigma2)) a typo? Because that raises a
syntax error for me.
-M. Hampton
On Oct 24, 6:12 am, Jason Grout [EMAIL PROTECTED] wrote:
LRN wrote:
Here's the code:
sigma = 0.2
gauss(x) = exp(-(x)2/(2*sigma2))
gauss1 = gauss(x).derivative
gauss2 = gauss1(x).derivative
ngauss2(x) = -1*gauss2(x)
sngauss2(x,y) = ngauss2(sqrt(x2 + y2))
a1 = var('a1'); a2 = var('a2'); b1 = var('b1'); b2 = var('b2')
chunkx = integral(sngauss2, x, a1, b1)
chunky = integral(chunkx, y, a2, b2)
chunky.show()
When evaluated it says It looks like jsMath failed to set up properly
(error code -7). I will try to keep going, but it could get ugly.
This is a problem with fonts, not with any math. To get the nice TeX
display with jsMath, please download a set of fonts from here:
http://www.math.union.edu/~dpvc/jsMath/download/jsMath-fonts.html
If you are on Unix, ignore the instructions on the page and just unzip
the fonts into your ~/.fonts directory.
Please let us know if that solves the problem.
We *really* ought to fix this to behave nicer (i.e., instead of just
giving an error, just offer to give the fonts to the user and give them
instructions for installing them). Of course, I've said this before,
but not done anything about it!
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: accessing a notebook on a remote machine
Yes, confirmed. I now just use the computer name because it is a lot easier to remember. :) Is there an easy way to prevent someone from accidentally deleting data on the computer? Just login from a restricted account before opening the notebook, or do I have to set up a chroot jail? Thanks! Jason Grout wrote: You should also be able to do: notebook(address=computername, port=8100, secure=True) to be able to address it as just https://computername:8100. That might work anyway even with address='ipaddress' too. 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: Problems with .show() and integration
Marshall Hampton wrote: Is gauss(x) = exp(-(x)2/(2*sigma2)) a typo? Because that raises a syntax error for me. Should that be: gauss(x) = exp(-(x)^2/(2*sigma^2)) sometimes my copy and paste strip the ^ signs; is that what happened? 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] bug in simplify_radical()?
Dear all,
I just noted some strange behaviour with simplify_radical():
--
| SAGE Version 3.1.2, Release Date: 2008-09-19 |
| Type notebook() for the GUI, and license() for information.|
--
sage: sage: var('a b c')
(a, b, c)
sage: ((a*b - 0.5*a*(b - c))/a).simplify_radical()
0
sage: ((b - 0.5*(b - c))).simplify_radical()
0.500*c + 0.500*b
Clearly, the second result should be the same as the first one, as 'a'
cancels out. Does anyone know how to avoid such mistakes and whether
it is advisable to use simplify_radical at all?
Cheers
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: bug in simplify_radical()?
A variation on your first try is:
sage: ((a*b - (1/2)*a*(b - c))/a).simplify_radical()
(c + b)/2
which works fine. Maybe it's a bug in maxima. I don't see why you
would need simplify_radical() at all here, since your expression
contains no radicals.
John Cremona
2008/10/24 Stan Schymanski [EMAIL PROTECTED]:
Dear all,
I just noted some strange behaviour with simplify_radical():
--
| SAGE Version 3.1.2, Release Date: 2008-09-19 |
| Type notebook() for the GUI, and license() for information.|
--
sage: sage: var('a b c')
(a, b, c)
sage: ((a*b - 0.5*a*(b - c))/a).simplify_radical()
0
sage: ((b - 0.5*(b - c))).simplify_radical()
0.500*c + 0.500*b
Clearly, the second result should be the same as the first one, as 'a'
cancels out. Does anyone know how to avoid such mistakes and whether
it is advisable to use simplify_radical at all?
Cheers
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: bug in simplify_radical()?
That's interesting. It seems that the bug lies in the use of floating
point numbers? By the way, simplify_trig and simplify_rational create
the same mistake. I agree that the use of simplify_radical() is not
very useful here, but if it makes such an obvious mistake, how
confident can we be that it doesn't make mistakes in more complicated
cases where we don't actually notice the mistake straight away? I
thought about using something like simplify_full() on any equation to
see if it can be simplified before I carry on with calculations.
Perhaps this is the wrong strategy, anyway. Any comments?
How could I actually get Sage to cancel out the 'a' in the equation?
None of the methods I tried do the job. I don't like doing things by
hand, because then I have to redo everything if I change an equation
somewhere at the top of the notebook.
Thanks a lot for thinking about it!
Stan
On Oct 24, 3:04 pm, John Cremona [EMAIL PROTECTED] wrote:
A variation on your first try is:
sage: ((a*b - (1/2)*a*(b - c))/a).simplify_radical()
(c + b)/2
which works fine. Maybe it's a bug in maxima. I don't see why you
would need simplify_radical() at all here, since your expression
contains no radicals.
John Cremona
2008/10/24 Stan Schymanski [EMAIL PROTECTED]:
Dear all,
I just noted some strange behaviour with simplify_radical():
--
| SAGE Version 3.1.2, Release Date: 2008-09-19 |
| Type notebook() for the GUI, and license() for information. |
--
sage: sage: var('a b c')
(a, b, c)
sage: ((a*b - 0.5*a*(b - c))/a).simplify_radical()
0
sage: ((b - 0.5*(b - c))).simplify_radical()
0.500*c + 0.500*b
Clearly, the second result should be the same as the first one, as 'a'
cancels out. Does anyone know how to avoid such mistakes and whether
it is advisable to use simplify_radical at all?
Cheers
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: bug in simplify_radical()?
On Friday 24 October 2008 15:17:57 Stan Schymanski wrote:
That's interesting. It seems that the bug lies in the use of floating
point numbers? By the way, simplify_trig and simplify_rational create
the same mistake. I agree that the use of simplify_radical() is not
very useful here, but if it makes such an obvious mistake, how
confident can we be that it doesn't make mistakes in more complicated
cases where we don't actually notice the mistake straight away? I
thought about using something like simplify_full() on any equation to
see if it can be simplified before I carry on with calculations.
Perhaps this is the wrong strategy, anyway. Any comments?
How could I actually get Sage to cancel out the 'a' in the equation?
None of the methods I tried do the job. I don't like doing things by
hand, because then I have to redo everything if I change an equation
somewhere at the top of the notebook.
In this case, expand seems to do what you want. I don't know if it will help
you with more complex expressions.
sage: var(a,b,c)
(a, b, c)
sage: e = ((a*b - (1/2)*a*(b - c))/a); e
(a*b - a*(b - c)/2)/a
sage: e.expand()
c/2 + b/2
or with float coefficients:
sage: e = ((a*b - (.5)*a*(b - c))/a); e
(a*b - 0.500*a*(b - c))/a
sage: e.expand()
0.500*c + 0.500*b
On Oct 24, 3:04 pm, John Cremona [EMAIL PROTECTED] wrote:
A variation on your first try is:
sage: ((a*b - (1/2)*a*(b - c))/a).simplify_radical()
(c + b)/2
which works fine. Maybe it's a bug in maxima. I don't see why you
would need simplify_radical() at all here, since your expression
contains no radicals.
John Cremona
2008/10/24 Stan Schymanski [EMAIL PROTECTED]:
Dear all,
I just noted some strange behaviour with simplify_radical():
--
| SAGE Version 3.1.2, Release Date: 2008-09-19 |
| Type notebook() for the GUI, and license() for information. |
--
sage: sage: var('a b c')
(a, b, c)
sage: ((a*b - 0.5*a*(b - c))/a).simplify_radical()
0
sage: ((b - 0.5*(b - c))).simplify_radical()
0.500*c + 0.500*b
Clearly, the second result should be the same as the first one, as 'a'
cancels out. Does anyone know how to avoid such mistakes and whether
it is advisable to use simplify_radical at all?
Cheers
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: bug in simplify_radical()?
2008/10/24 Stan Schymanski [EMAIL PROTECTED]:
That's interesting. It seems that the bug lies in the use of floating
point numbers? By the way, simplify_trig and simplify_rational create
the same mistake. I agree that the use of simplify_radical() is not
very useful here, but if it makes such an obvious mistake, how
confident can we be that it doesn't make mistakes in more complicated
cases where we don't actually notice the mistake straight away? I
thought about using something like simplify_full() on any equation to
see if it can be simplified before I carry on with calculations.
Perhaps this is the wrong strategy, anyway. Any comments?
How could I actually get Sage to cancel out the 'a' in the equation?
None of the methods I tried do the job. I don't like doing things by
hand, because then I have to redo everything if I change an equation
somewhere at the top of the notebook.
Here's an approach which does not use maxima at all, but rather more
pure algebra:
sage: R.a,b,c = QQ[]
sage: (a*b - (1/2)*a*(b - c))//a
1/2*b + 1/2*c
Here, R is the set of all polynomials in a,b,c with rational
coefficients, and // does an exact division. (If you use / instead
the answer looks the same but lies in a different place:
sage: parent((a*b - (1/2)*a*(b - c))/a)
Fraction Field of Multivariate Polynomial Ring in a, b, c over Rational Field
sage: parent((a*b - (1/2)*a*(b - c))//a)
Multivariate Polynomial Ring in a, b, c over Rational Field
Now, whether or not you like this solution seems to depend on whether
or not you are a pure mathematician who is used to rings and fields,
as opposed so someone who just deals with symbolic expressions. The
former are much faster (and, as in this case, more accurate!) but are
conceptually harder -- and do not allow things like radicals and
exponentials.
John Cremona
Thanks a lot for thinking about it!
Stan
On Oct 24, 3:04 pm, John Cremona [EMAIL PROTECTED] wrote:
A variation on your first try is:
sage: ((a*b - (1/2)*a*(b - c))/a).simplify_radical()
(c + b)/2
which works fine. Maybe it's a bug in maxima. I don't see why you
would need simplify_radical() at all here, since your expression
contains no radicals.
John Cremona
2008/10/24 Stan Schymanski [EMAIL PROTECTED]:
Dear all,
I just noted some strange behaviour with simplify_radical():
--
| SAGE Version 3.1.2, Release Date: 2008-09-19 |
| Type notebook() for the GUI, and license() for information.|
--
sage: sage: var('a b c')
(a, b, c)
sage: ((a*b - 0.5*a*(b - c))/a).simplify_radical()
0
sage: ((b - 0.5*(b - c))).simplify_radical()
0.500*c + 0.500*b
Clearly, the second result should be the same as the first one, as 'a'
cancels out. Does anyone know how to avoid such mistakes and whether
it is advisable to use simplify_radical at all?
Cheers
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: bug in simplify_radical()?
Burcin Erocal wrote: On Friday 24 October 2008 15:17:57 Stan Schymanski wrote: That's interesting. It seems that the bug lies in the use of floating point numbers? By the way, simplify_trig and simplify_rational create the same mistake. I agree that the use of simplify_radical() is not very useful here, but if it makes such an obvious mistake, how confident can we be that it doesn't make mistakes in more complicated cases where we don't actually notice the mistake straight away? I thought about using something like simplify_full() on any equation to see if it can be simplified before I carry on with calculations. Perhaps this is the wrong strategy, anyway. Any comments? How could I actually get Sage to cancel out the 'a' in the equation? None of the methods I tried do the job. I don't like doing things by hand, because then I have to redo everything if I change an equation somewhere at the top of the notebook. In this case, expand seems to do what you want. I don't know if it will help you with more complex expressions. sage: var(a,b,c) (a, b, c) sage: e = ((a*b - (1/2)*a*(b - c))/a); e (a*b - a*(b - c)/2)/a sage: e.expand() c/2 + b/2 or with float coefficients: sage: e = ((a*b - (.5)*a*(b - c))/a); e (a*b - 0.500*a*(b - c))/a sage: e.expand() 0.500*c + 0.500*b In general, I find that expand will end up simplifying things a lot more than the simplify functions will. I suppose it's like our secondary school math: when in doubt, multiply everything out and then see what cancels. 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: bug in simplify_radical()?
Thanks for the advice! It seems like a combination of expand() and simplify() would go a long way. Unfortunately, I am not a Mathematician and hence struggle to understand rings and fields. I am still a bit hesitant about simplify, though. Should a bug report be filed to Maxima? By the way, is pynac going to replace the maxima simplify algorithms? It seems that there is some potential for improvement there. 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: bug in simplify_radical()?
On Friday 24 October 2008 16:20:24 Stan Schymanski wrote: Thanks for the advice! It seems like a combination of expand() and simplify() would go a long way. Unfortunately, I am not a Mathematician and hence struggle to understand rings and fields. I am still a bit hesitant about simplify, though. Should a bug report be filed to Maxima? By the way, is pynac going to replace the maxima simplify algorithms? It seems that there is some potential for improvement there. Eventually, yes. To be able to extend / improve / customize such maxima functions is one of the main reasons behind the pynac backed symbolics effort. Cheers, Burcin --~--~-~--~~~---~--~~ 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: How to detect memory leaks?
Dear Carlo and all others, On Oct 23, 5:11 pm, Carlo Hamalainen [EMAIL PROTECTED] wrote: Valgrind is the thing to try:http://wiki.sagemath.org/ValgrindingSage Sorry, when I read the first lines of that page I thought I had to re- build Sage from scratch. But later it says that there is an optional valgrind package for Sage. I installed it and tried sage -valgrind. Then I did sage: attach f5.pyx Compiling /home/king/Projekte/f5/f5.pyx... sage: from sage.rings.ideal import Cyclic sage: R=PolynomialRing(QQ,'x',5) sage: I=Cyclic(R).homogenize() sage: get_memory_usage() 1013.09765625 sage: F=F5() sage: G1=F(I) sage: del F sage: del G1 sage: get_memory_usage() 1035.59765625 sage: F=F5() sage: G1=F(I) sage: del F sage: del G1 sage: get_memory_usage() 1053.04296875 sage: quit However, it didn't help much. The valgrind output available at http://sage.math.washington.edu/home/SimonKing/f5/sage-memcheck.18590 says in the summary that ~386kB are possibly lost and nothing is definitely lost. I think this doesn't fit to the output of get_memory_usage() above. Running F=F5()G=F(I) in a loop is soon eating all memory. Moreover, most of the valgrind output does not refer to my code, as much as I understand. Hence, there is only a handful of references to _home_king_Projekte_f5_f5_pyx_0.c Can you help me with interpreting the valgrind findings? Thank you very much Simon --~--~-~--~~~---~--~~ 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: How to detect memory leaks?
On Oct 24, 8:52 am, Simon King [EMAIL PROTECTED] wrote: Dear Carlo and all others, On Oct 23, 5:11 pm, Carlo Hamalainen [EMAIL PROTECTED] wrote: Valgrind is the thing to try:http://wiki.sagemath.org/ValgrindingSage Sorry, when I read the first lines of that page I thought I had to re- build Sage from scratch. But later it says that there is an optional valgrind package for Sage. I installed it and tried sage -valgrind. You need to rebuild Python after exporting SAGE_VALGRIND=yes - otherwise pymalloc is used and as is the valgrind log is useless in some regards. Then I did sage: attach f5.pyx Compiling /home/king/Projekte/f5/f5.pyx... sage: from sage.rings.ideal import Cyclic sage: R=PolynomialRing(QQ,'x',5) sage: I=Cyclic(R).homogenize() sage: get_memory_usage() 1013.09765625 sage: F=F5() sage: G1=F(I) sage: del F sage: del G1 sage: get_memory_usage() 1035.59765625 sage: F=F5() sage: G1=F(I) sage: del F sage: del G1 sage: get_memory_usage() 1053.04296875 sage: quit However, it didn't help much. The valgrind output available athttp://sage.math.washington.edu/home/SimonKing/f5/sage-memcheck.18590 says in the summary that ~386kB are possibly lost and nothing is definitely lost. I think this doesn't fit to the output of get_memory_usage() above. Running F=F5() G=F(I) in a loop is soon eating all memory. Moreover, most of the valgrind output does not refer to my code, as much as I understand. Hence, there is only a handful of references to _home_king_Projekte_f5_f5_pyx_0.c Can you help me with interpreting the valgrind findings? The key thing here is that the still reachable amount of memory is growing which indicates a problem with objects from the python heap not getting properly deallocated, i.e. a potential reference count issue when using Cython for example. Debugging these is hard and valgrind will not help much in that case. Much more useful could be Guppy. Thank you very much Simon 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: Problems with .show() and integration
On 24.10.2008 15:48, Jason Grout wrote: Marshall Hampton wrote: Is gauss(x) = exp(-(x)2/(2*sigma2)) a typo? Because that raises a syntax error for me. Should that be: gauss(x) = exp(-(x)^2/(2*sigma^2)) sometimes my copy and paste strip the ^ signs; is that what happened? Yes, it's ^. --~--~-~--~~~---~--~~ 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: Is interact partly broken in 3.1.4 (or before)?
The automatic evaluation of interact cells bothers me; I think it would be better if this was changed. Is it not enough to use #auto? - William's comments suggest things are more complicated, but if not #auto already provides the same mechanism. +1 to interact cells not auto-evaluating, since we can already do this with #auto. This is now http://trac.sagemath.org/sage_trac/ticket/4363 Weirdly, I cannot now reproduce the disappearing slider issue, even though it was consistent a few days ago with 3.1.4+. If it crops up again I will report back. - 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: Problems with .show() and integration
On 24.10.2008 15:12, Jason Grout wrote: Please let us know if that solves the problem. It does. --~--~-~--~~~---~--~~ 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] Quantlib (SWIG) and Sage - Experimental package
Hi All, I have successfully compiled the new quantlib_swig-0.9.6 quantlib-0.9.6 packages from Sage 3.0.1. A number of functions work fine form the Sage notebook. Unfortunately the important quantlib Date() function is causing problems. I am trying to run from QuantLib import * calendar = TARGET() todaysDate = Date(6,October,2001) and I get the error: Traceback (most recent call last): File stdin, line 1, in module File /root/.sage/sage_notebook/worksheets/tomanizer/18/code/3.py, line 7, in module todaysDate = Date(Integer(6),October,Integer(2001)) File /filesrv/Sage/sage-3.0.2-debian32-intelx86-i686-Linux/local/ lib/python2.5/site-packages/sympy/plotting/, line 1, in module File /filesrv/Sage/sage-3.0.2-debian32-intelx86-i686-Linux/local/ lib/python2.5/site-packages/QuantLib/QuantLib.py, line 203, in __init__ this = _QuantLib.new_Date(*args) NotImplementedError: Wrong number of arguments for overloaded function 'new_Date'. Possible C/C++ prototypes are: Date() Date(Day,Month,Year) Date(BigInteger) Date(std::string const ,std::string const ) which is an error thrown by SWIG if the wrong parameters are passed to the functions. However, this example is from the Quantlib SWIG help file. So I assume it should work from quantlib SWIG. My suspicion is that the error is related to the Sage's handling of unicode. Does anone wlse have this problem? Is there a workaround? Kind regards Thomas --~--~-~--~~~---~--~~ 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: Maple 11 in Sage
I just wanted to second this problem. When I run a Maple command in the Sage Notebook (Sage 3.1.2 on OSX 10.4), I have to execute the cell three times to see the output. The first time I execute, I get no output at all. The second time, I get an output that's something like read /Users/jacobml/.sage//temp/dhcp224198.local/53206//interface//tmp532 and the third time I actually get the expected output--plus some garbage. For example, if I execute Weierstrassform(x^3+y^3+1,x,y,x0,y0) (after loading the algcurves package) I get output read /Users/jacobml/.sage//temp/dhcp224198.local/53206//interface// tmp53206\ ; read /Users/jacobml/.sage//temp/dhcp224198.local/53206//interface// tmp53206\ ; read /Users/jacobml/.sage//temp/dhcp224198.local/53206//interface// tmp53206\ ; [x0^3+27/4+y0^2, -3*y^2+3*y*x-3*x^2, 9*y^2*x-9*y*x^2+9*x^3+9/2, 1/6*(9-2*y0)/ x0, 1/6*(9+2*y0)/x0] -Jacob On Oct 12, 12:50 am, William Stein [EMAIL PROTECTED] wrote: Andrey, I'm sending this to sage-support. On Sun, Oct 12, 2008 at 12:53 AM, Andrey Novoseltsev [EMAIL PROTECTED] wrote: Dear William, I have problems usingMaple11 from Sage - it does something, but something is broken in the interface. Is it easy to fix and if yes, how? Below is a sample session. Thank you, Andrey [EMAIL PROTECTED]:~$ ./sage-3.1.2/sage -- | SAGE Version 3.1.2, Release Date: 2008-09-19 | | Type notebook() for the GUI, and license() for information. | -- sage:maple.eval(1+1) 'read /home/novoseltsev/.sage//temp/numbers.math.ualberta.ca/18866//interf' sage:maple.eval(1+1) '' sage:maple.eval(1+1) '2' sage:maple.eval(1+1) 'read /home/novoseltsev/.sage//temp/numbers.math.ualberta.ca/18866//interf' sage:maple.eval(1+1) '' sage:maple.eval(1+1) '2' sage:maple.eval(1+1) 'read /home/novoseltsev/.sage//temp/numbers.math.ualberta.ca/18866//interf' sage:maple.eval() '' sage:maple.eval() '' sage:maple.eval() '' sage:maple.eval() '' sage:maple.eval() '' sage: exit Exiting SAGE (CPU time 0m0.05s, Wall time 16m59.57s). Exiting spawnedMapleprocess. [EMAIL PROTECTED]:~$maple |\^/| Maple11 (X86 64 LINUX) ._|\| |/|_. Copyright (c) Maplesoft, a division of WaterlooMapleInc. 2007 \ MAPLE / All rights reserved.Mapleis a trademark of WaterlooMapleInc. | Type ? for help. -- William Stein Associate Professor of Mathematics University of Washingtonhttp://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 -~--~~~~--~~--~--~---
