[sage-devel] Re: Solve-left for systems over CDF/RDF
On Feb 18, 9:02 am, Jason Grout wrote: > So I guess you're volunteering to fix #7852 and possibly #4932? Hooray! Maybe. Thanks for #7852 - I didn't know that one. Might as well add #7392 (which I have started on). Rob -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Re: Rapid growth in Python popularity
> > > > As for the conjecture that Python is wildly popular and > > therefore the perfect choice for computational mathematics > > I can only point to history. Pascal was everywhere, including > > in the universities. Smalltalk took the world by storm. > > PL/I was universal. Ada was the ultimate language. Most > > people probably don't even list these languages on their > > resume anymore. Wait 10 years. Nobody will admit to knowing > > Python. > > Your summarization of history indicates that no language will survive > 10 years, so we should pick a language not on its long-term merits but > based on getting something out of it before it "fades." > Hasty generalization. Fortran, Lisp and C are still active and they are 50 years old so some languages are still resume material. Pascal, in its day, was HOT. Universities switched to Pascal for teaching, books were using it as pseudocode, and great debates raged about its bike-shed issues (e.g. a lack of strings). It was the easiest language to write. It was easy to compile. It was required as a line-item on your resume. It cured cancer and was the key to worldwide understanding. Famous people in history were renamed after the language! Surely everyone you know codes in Pascal, right? Is Python a Fortran or a Pascal? Well, lets look for some data about how others choose. I have touched nearly every computational math program on the planet over the years. On my Ubuntu linux system almost every python program I didn't write is some sort of a system script so it seems to have moved into Perl's primary domain. From that data point I'd say that Python is a great language to know if you plan to be a sysadmin. (I excluded Sage, of course). Sympy and numpy are exceptions. But even Java people use python for scripting and test (e.g. inside ant). On my Ubuntu linux system almost every computational math program I didn't write is either Fortran, Lisp, C, C++, assembler or some specialized math language like Spad, MMA, Maple, etc. From that data point I'd say that Python is not a computational mathematics language of note. >From the data it seems that Python is "the new Perl", a new, improved system scripting language; a glue language for the new millenium. That might explain why it appears to be so popular and why Perl is sinking in the TIOBE ratings. Would you do computational math in Perl? Tim Daly -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Patchbot and alpha versions
On Fri, Feb 18, 2011 at 6:28 AM, Jeroen Demeyer wrote: > On 2011-02-18 14:57, Simon King wrote: >> I could imagine that it would not be feasible to let the patchbot >> operate with a multitude of different sage versions. But perhaps it >> would be doable to let it work with *two* versions: 1. the latest >> release (default), 2. the latest alpha version. > > Why not *only* the latest alpha? That would make more sense to me. Because 1) Some people, myself included, don't enjoy downloading and rebuilding every alpha that comes out and 2) While alphas are much more stable than they used to be, it's nice to start with a clean, known, working base. Remember how much less useful the bot was when everything had the same failing test (though eventually we could logic in place to let green be "no regressions with this ticket" rather than all tests passed). That being said, the patchbot is written as two separate components, the bot and the server. The intent is to ship the bot itself with Sage (maybe I'll get motivated enough to get it into 4.6.2) and so anyone can test tickets on any hardware they want. This will give us platform, hardware, and version diversity. There would still be a centralized server. (Well, people could run their own servers if they want, but that's not terribly useful.) The server itself is written to handle versioning, e.g. http://sage.math.washington.edu:21100/ticket/?base=4.6 - Robert -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Re: Rapid growth in Python popularity
On 18 February 2011 05:11, rjf wrote: > > > On Feb 17, 4:49 pm, Matt Goodman wrote: >> MATLAB isn't a tool used outside of academia very often. > > I think you are wrong here. I don't have any data to point to though. > Do you have any data on this? Matt is definitely VERY wrong. MATLAB is well used in industry. Just look on any job site and stick in MATLAB as a keyword and you will find many jobs that want MATLAB skills. It's my experience as an engineer that it is the most popular of all the scientific computing environments. The simulink toolbox is also very well used in industry. Dave Dave -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Patchbot and ticket comments
On Fri, Feb 18, 2011 at 6:20 AM, Jeroen Demeyer wrote: > On 2011-02-18 00:27, Robert Bradshaw wrote: >>> 2) The ticket description can be *edited*, comments not. For example, >>> if some comments just mention a new spkg, then the patchbot will >>> automatically think it's a dependency, even when it's not. >> >> Again, I see this as a disadvantage, because then there's no history >> or ordering to look at. > > So how do I convince the patchbot that the spkgs mentioned in #2329 > aren't actually dependencies? You can't right now, but the solution would be similar to depends on and patches, have an spks: ... comment reset the spkg list. That should be a pretty easy fix once I find the time. - Robert -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] Re: Rapid growth in Python popularity
Hi On Feb 17, 6:49 pm, Matt Goodman wrote: > MATLAB isn't a tool used outside of academia very often. I am loathe to involve myself in this conversation, but: I'm aware that MATLAB is used by people at NASA, in the Navy, and at Raytheon. I seriously doubt that approaches even a tenth of MATLAB's non-academic users, and in any case this alone is a huge amount. I have no idea what its proportion is vs. scientific python, and doubtless there is some overlap, but 2x sounds way too small. regards john perry -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Re: Rapid growth in Python popularity
On Fri, Feb 18, 2011 at 10:26 AM, rjf wrote: > > > On Feb 18, 8:51 am, William Stein wrote: >> >> At University of Washington, even with a site license, MATLAB costs me >> $100, so I don't have it on my laptop. >> There are limited licenses for students, and I've been told they have >> trouble doing homework assignments, due to >> sharing those licenses. > > FUD? > It seems to me that if I were writing useful/important code that > paying > $100 would not be such a bad idea, though I agree that "free" would be > "better". There's a difference between costing the university $100 and costing the individual user $100... The financial drawbacks are also significant if one is forced to pay per-core license on your new shiny cluster or supercomputer. > I would have reservations though if the university gave me > a "free" copy but told me that any program that I wrote using it could > never be sold by me to anyone. It would have to be owned by the > university > (as work for hire), sometimes a university policy. Or it would have > to be given away free (Sage, GPL) policy. Yes, that would be worrisome indeed, but that's not the case. >> In my experience, installing MATLAB is much more difficult than >> installing Sage. > > That may be your personal experience, but I wonder how widely > shared it is? I have only read about installing Sage, so I cannot tell > for sure, but > it seems that installing on Windows is difficult. Many people post > comments about difficulty compiling it, but not everyone compiles it, > I hope. > So maybe it is easy sometimes. > > I have not installed my own copy of (Windows) Matlab for years, > but I assume it still requires downloading a matlab_installer.exe > and clicking on it, then perhaps typing the name of the license > server. > Installing software on a properly installed Linux system is even > easier > in the best case (where you have right permissions etc). > > > >> I can imagine no worse hell than being asked to >> install a working MATLAB on a bunch of random Linux, OS X, and Windows >> boxes. > > That's probably why system administrators are paid, except > when professors act as their own system administrators. > Even "free" > software can require time and skill to install. > >> >> >> > I am not surprised that there is a relatively small overlap between >> >> > scientific >> >> > computing and Python programming. Most scientific computing tasks are >> >> > sensitive >> >> > to efficiency of resulting code. >> >> >> This is just FUD, suggesting that one can't use Python for scientific >> >> computing due to it being too slow. >> >> > Well, the issue is not so much the programming language efficiency, >> > or how much it matters in practice to have some data setup and web >> > access >> > and debugging be written in a friendlier languaage, but a perception. >> >> Thus your FUD is all the more damaging > > Read the article posted by Tim Daly.. >> >> >> Most people doing scientific also >> >> use C/Fortran-based libraries such as numpy and scipy, and quite a few >> >> use Cython as well. >> >> > Can't those libraries (or something like them) also be called from C >> > or Fortran? >> >> If those libraries = "numpy/scipy", then absolutely not. Most of the >> code in numpy is new code, which provides a different and powerful >> perspective on n-dimensional data manipulation that isn't provided by >> any underlying library it depends on (BLAS). Some of scipy is just >> wrapping Fortran libraries, and some (quite a bit) is new code not >> wrapping anything. >> > > > I think the right perspective is shown here. I think you are actually agreeing here, wow ;). What's more amazing is this is pretty much exactly the perspective for Sage as a whole. > You can use Python to wrap > what most people consider the scientific computing core systems. > Writing those core systems in Python is not particularly credible. > But wrapping difficult-to-use programs in nicer "higher level" ways > may be a worthy endeavor. That and building higher-level algorithms on top of lower-level libraries, e.g. modular form computations that leverage existing low-level linear algebra libraries. > ( a somewhat unfair analogy --- > We do not say that the rapid proliferation > of cell phones means they are increasingly being used to write > internet communications software... > > That's what I was driving at in my question that you chose to > ignore.. > > "Oh, that reminds me, what is Lapack written in? > Do you think it would benefit by rewriting in Python or Cython? > What about Scalapack, BLAS, etc. " ) > > In terms of Jan's comment -- I'm not sure the barrier to entry is > lowest for Python -- There are lots of contenders, and it is not > obvious which is the winner. In some circumstances, I've found > that Visual Basic or JScript (ECMAscript/) are trivial. Python has > other useful attributes though. > > Anyway, if we say that people who wrap FORTRAN programs in python are >
Re: [sage-devel] Re: Rapid growth in Python popularity
On Fri, Feb 18, 2011 at 12:12 PM, daly wrote: >> The python community is huge, skills are available, >> and often the needs are not in the core science algorithm >> which is well looked after, but in the glue and interface, >> which requires a less in-depth understanding of the science >> than the core algorithm. It allows non-niche programmers to assist >> more easily than... FORTRAN. > > I do think Sage has proven the conjecture that Python is an excellent > choice for a glue language (although a lot of the actual glue seems > to be in Cython?). Cython happens to be a particularly nice "glue" when it comes to interfacing with C libraries. I would however say that the majority of code in Sage (both Python and Cython) is not glue (though we of course don't write our own BLAS or integer multiplication routines). > Since Sage is growing by accretion, William made an > excellent choice. > > I don't think Sage has proven the conjecture that Python is good > for computational mathematics. My experience with computational > mathematicians is that they will program in obscure (APL) or > dead (Fortran) languages. Every one I have met over the years > is perfectly capable of writing their algorithms in anything. > > There are two ways to look at any computational mathematics > problem. Either you want something very close to the math, > (e.g. Spad) for conceptual efficiency or very close to the > machine (e.g. C) for execution efficiency. Python sits > somewhere between these two extremes, making it a non-optimal > choice for either. But if Python is good enough, even if not optimal, to reasonably do work on both ends of the spectrum, then the advantage to using a single language can outweigh the advantage of using specialized languages for individual tasks with lost of glue code and context switching. This is especially true for code that starts out close to the math and then can be optimized (rather than re-written) for execution efficiency. > If I were working with Sage I'd write my algorithm in some > other language and "glue it on" with python. > > As for the conjecture that Python is wildly popular and > therefore the perfect choice for computational mathematics > I can only point to history. Pascal was everywhere, including > in the universities. Smalltalk took the world by storm. > PL/I was universal. Ada was the ultimate language. Most > people probably don't even list these languages on their > resume anymore. Wait 10 years. Nobody will admit to knowing > Python. Your summarization of history indicates that no language will survive 10 years, so we should pick a language not on its long-term merits but based on getting something out of it before it "fades." - Robert -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Re: Rapid growth in Python popularity
You can back out pyc's pretty easy. See the "byteplay" package. :) --Matthew Goodman = Check Out My Website: http://craneium.net Find me on LinkedIn: http://tinyurl.com/d6wlch On Fri, Feb 18, 2011 at 2:26 PM, Eviatar wrote: > On Feb 18, 10:26 am, rjf wrote: > > On Feb 18, 8:51 am, William Stein wrote: > > FUD? > > It seems to me that if I were writing useful/important code that > > paying > > $100 would not be such a bad idea, though I agree that "free" would be > > "better". I would have reservations though if the university gave me > > a "free" copy but told me that any program that I wrote using it could > > never be sold by me to anyone. It would have to be owned by the > > university > > (as work for hire), sometimes a university policy. Or it would have > > to > > be given away free (Sage, GPL) policy. > This is untrue. The GPL covers Sage itself, not code written for Sage. > I'm fairly certain you could sell it with no license problems. > Obfuscation, though, is another issue, but I think .pyc files would > work. Of course, this goes against the whole philosophy of Sage. > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] Re: Rapid growth in Python popularity
On Feb 18, 10:26 am, rjf wrote: > On Feb 18, 8:51 am, William Stein wrote: > FUD? > It seems to me that if I were writing useful/important code that > paying > $100 would not be such a bad idea, though I agree that "free" would be > "better". I would have reservations though if the university gave me > a "free" copy but told me that any program that I wrote using it could > never be sold by me to anyone. It would have to be owned by the > university > (as work for hire), sometimes a university policy. Or it would have > to > be given away free (Sage, GPL) policy. This is untrue. The GPL covers Sage itself, not code written for Sage. I'm fairly certain you could sell it with no license problems. Obfuscation, though, is another issue, but I think .pyc files would work. Of course, this goes against the whole philosophy of Sage. -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Re: Rapid growth in Python popularity
> The python community is huge, skills are available, > and often the needs are not in the core science algorithm > which is well looked after, but in the glue and interface, > which requires a less in-depth understanding of the science > than the core algorithm. It allows non-niche programmers to assist > more easily than... FORTRAN. I do think Sage has proven the conjecture that Python is an excellent choice for a glue language (although a lot of the actual glue seems to be in Cython?). Since Sage is growing by accretion, William made an excellent choice. I don't think Sage has proven the conjecture that Python is good for computational mathematics. My experience with computational mathematicians is that they will program in obscure (APL) or dead (Fortran) languages. Every one I have met over the years is perfectly capable of writing their algorithms in anything. There are two ways to look at any computational mathematics problem. Either you want something very close to the math, (e.g. Spad) for conceptual efficiency or very close to the machine (e.g. C) for execution efficiency. Python sits somewhere between these two extremes, making it a non-optimal choice for either. If I were working with Sage I'd write my algorithm in some other language and "glue it on" with python. As for the conjecture that Python is wildly popular and therefore the perfect choice for computational mathematics I can only point to history. Pascal was everywhere, including in the universities. Smalltalk took the world by storm. PL/I was universal. Ada was the ultimate language. Most people probably don't even list these languages on their resume anymore. Wait 10 years. Nobody will admit to knowing Python. Tim Daly -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Re: Rapid growth in Python popularity
Regarding the academics comment, check this out: http://www.google.com/trends?q=matlab%2C+python&ctab=0&geo=all&date=all&sort=0 Matlab related dips notably (~50% peak to trough) during spring, winter, and summer breaks. All I really have to say about MATLAB is for a piece of software backed by millions of dollars of development, its pretty notably deficient. Deficient by design actually, I mean why include image processing routines, when you could charge more for that in a toolbox? There is nothing in there that you couldn't develop in < 1000 hours of competent developer time, using standard numerical recipes. I didn't mean to start a flame war here, just wanted to present some observations. --Matthew Goodman = Check Out My Website: http://craneium.net Find me on LinkedIn: http://tinyurl.com/d6wlch On Fri, Feb 18, 2011 at 12:26 PM, rjf wrote: > > > On Feb 18, 8:51 am, William Stein wrote: > > > > At University of Washington, even with a site license, MATLAB costs me > > $100, so I don't have it on my laptop. > > There are limited licenses for students, and I've been told they have > > trouble doing homework assignments, due to > > sharing those licenses. > > FUD? > It seems to me that if I were writing useful/important code that > paying > $100 would not be such a bad idea, though I agree that "free" would be > "better". I would have reservations though if the university gave me > a "free" copy but told me that any program that I wrote using it could > never be sold by me to anyone. It would have to be owned by the > university > (as work for hire), sometimes a university policy. Or it would have > to > be given away free (Sage, GPL) policy. > > > > > > In my experience, installing MATLAB is much more difficult than > > installing Sage. > > That may be your personal experience, but I wonder how widely > shared it is? I have only read about installing Sage, so I cannot tell > for sure, but > it seems that installing on Windows is difficult. Many people post > comments about difficulty compiling it, but not everyone compiles it, > I hope. > So maybe it is easy sometimes. > > I have not installed my own copy of (Windows) Matlab for years, > but I assume it still requires downloading a matlab_installer.exe > and clicking on it, then perhaps typing the name of the license > server. > Installing software on a properly installed Linux system is even > easier > in the best case (where you have right permissions etc). > > > > > I can imagine no worse hell than being asked to > > install a working MATLAB on a bunch of random Linux, OS X, and Windows > > boxes. > > That's probably why system administrators are paid, except > when professors act as their own system administrators. > Even "free" > software can require time and skill to install. > > > > > >> > I am not surprised that there is a relatively small overlap between > > >> > scientific > > >> > computing and Python programming. Most scientific computing tasks > are > > >> > sensitive > > >> > to efficiency of resulting code. > > > > >> This is just FUD, suggesting that one can't use Python for scientific > > >> computing due to it being too slow. > > > > > Well, the issue is not so much the programming language efficiency, > > > or how much it matters in practice to have some data setup and web > > > access > > > and debugging be written in a friendlier languaage, but a perception. > > > > Thus your FUD is all the more damaging > > Read the article posted by Tim Daly.. > > > > >> Most people doing scientific also > > >> use C/Fortran-based libraries such as numpy and scipy, and quite a few > > >> use Cython as well. > > > > > Can't those libraries (or something like them) also be called from C > > > or Fortran? > > > > If those libraries = "numpy/scipy", then absolutely not. Most of the > > code in numpy is new code, which provides a different and powerful > > perspective on n-dimensional data manipulation that isn't provided by > > any underlying library it depends on (BLAS). Some of scipy is just > > wrapping Fortran libraries, and some (quite a bit) is new code not > > wrapping anything. > > > > > I think the right perspective is shown here. You can use Python to > wrap > what most people consider the scientific computing core systems. > Writing those core systems in Python is not particularly credible. > But wrapping difficult-to-use programs in nicer "higher level" ways > may be a worthy endeavor. > > ( a somewhat unfair analogy --- > We do not say that the rapid proliferation > of cell phones means they are increasingly being used to write > internet communications software... > > That's what I was driving at in my question that you chose to > ignore.. > > "Oh, that reminds me, what is Lapack written in? >Do you think it would benefit by rewriting in Python or Cython? > What about Scalapack, BLAS, etc. " ) > > In terms of Jan's comment -- I'm not sure the barrier to entry is > lowest for
[sage-devel] Re: Rapid growth in Python popularity
On Feb 18, 8:51 am, William Stein wrote: > > At University of Washington, even with a site license, MATLAB costs me > $100, so I don't have it on my laptop. > There are limited licenses for students, and I've been told they have > trouble doing homework assignments, due to > sharing those licenses. FUD? It seems to me that if I were writing useful/important code that paying $100 would not be such a bad idea, though I agree that "free" would be "better". I would have reservations though if the university gave me a "free" copy but told me that any program that I wrote using it could never be sold by me to anyone. It would have to be owned by the university (as work for hire), sometimes a university policy. Or it would have to be given away free (Sage, GPL) policy. > > In my experience, installing MATLAB is much more difficult than > installing Sage. That may be your personal experience, but I wonder how widely shared it is? I have only read about installing Sage, so I cannot tell for sure, but it seems that installing on Windows is difficult. Many people post comments about difficulty compiling it, but not everyone compiles it, I hope. So maybe it is easy sometimes. I have not installed my own copy of (Windows) Matlab for years, but I assume it still requires downloading a matlab_installer.exe and clicking on it, then perhaps typing the name of the license server. Installing software on a properly installed Linux system is even easier in the best case (where you have right permissions etc). > I can imagine no worse hell than being asked to > install a working MATLAB on a bunch of random Linux, OS X, and Windows > boxes. That's probably why system administrators are paid, except when professors act as their own system administrators. Even "free" software can require time and skill to install. > > >> > I am not surprised that there is a relatively small overlap between > >> > scientific > >> > computing and Python programming. Most scientific computing tasks are > >> > sensitive > >> > to efficiency of resulting code. > > >> This is just FUD, suggesting that one can't use Python for scientific > >> computing due to it being too slow. > > > Well, the issue is not so much the programming language efficiency, > > or how much it matters in practice to have some data setup and web > > access > > and debugging be written in a friendlier languaage, but a perception. > > Thus your FUD is all the more damaging Read the article posted by Tim Daly.. > > >> Most people doing scientific also > >> use C/Fortran-based libraries such as numpy and scipy, and quite a few > >> use Cython as well. > > > Can't those libraries (or something like them) also be called from C > > or Fortran? > > If those libraries = "numpy/scipy", then absolutely not. Most of the > code in numpy is new code, which provides a different and powerful > perspective on n-dimensional data manipulation that isn't provided by > any underlying library it depends on (BLAS). Some of scipy is just > wrapping Fortran libraries, and some (quite a bit) is new code not > wrapping anything. > I think the right perspective is shown here. You can use Python to wrap what most people consider the scientific computing core systems. Writing those core systems in Python is not particularly credible. But wrapping difficult-to-use programs in nicer "higher level" ways may be a worthy endeavor. ( a somewhat unfair analogy --- We do not say that the rapid proliferation of cell phones means they are increasingly being used to write internet communications software... That's what I was driving at in my question that you chose to ignore.. "Oh, that reminds me, what is Lapack written in? Do you think it would benefit by rewriting in Python or Cython? What about Scalapack, BLAS, etc. " ) In terms of Jan's comment -- I'm not sure the barrier to entry is lowest for Python -- There are lots of contenders, and it is not obvious which is the winner. In some circumstances, I've found that Visual Basic or JScript (ECMAscript/) are trivial. Python has other useful attributes though. Anyway, if we say that people who wrap FORTRAN programs in python are called "scientific computing" programmers, maybe we need another name for the people who write those FORTRAN (or C or whatever) programs. None of this really affects the validity of the Tiobe data which says that Python "Tiobe popularity index" is higher than ever. RJF -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] Re: Series expansion.
Continuing my example:
sage: maxima(f).powerseries('r',infinity)
-4*r*'sum((2^(2*i3-1)-1)*2^(2*i3-1)*bern(2*i3)*r^(2*i3-1)/
(2*i3)!,i3,0,inf)
(NOT CHECKED)
A Ch
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Re: [sage-devel] Series expansion.
Dox ask : I'd like to know if there is a way of finding the series expansion of a given function around zero and infinity. Around 0 : sage: taylor (2*x/sinh(2*x), x, 0, 10) -292/13365*x^10 + 254/4725*x^8 - 124/945*x^6 + 14/45*x^4 - 2/3*x^2 + 1 I see that the serie is right, even if partial computations must go one order after. I can't get the serie around +oo with sinh, but it's possible with exp. (I don't verify the result) sage: taylor (2*1/x/((exp(2/x)-exp(-2/x))/2), x, 0, 12) 4*e^(-10/x)/x + 4*e^(-6/x)/x + 4*e^(-2/x)/x There is this rewrite function at http://wiki.sagemath.org/symbolics/rewrite Is it possible? F. -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] Re: Series expansion.
sage: var('r');
sage: f=2*r/sinh(2*r)
sage: f.taylor(r,0,5)
14/45*r^4 - 2/3*r^2 + 1
sage: maxima(f).powerseries('r',0)
-4*r*'sum((2^(2*i2-1)-1)*2^(2*i2-1)*bern(2*i2)*r^(2*i2-1)/
(2*i2)!,i2,0,inf)
Andrzej Chrzeszczyk
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[sage-devel] Re: Rapid growth in Python popularity
On Feb 17, 11:06 pm, daly wrote: > An interesting article about computational science > programming:http://www.nature.com/news/2010/101013/full/467775a.html?ref=nf > > Tim Daly I find it especially interesting to see the comments about python ... search on that web page for each occurrence of "python". RJF -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] Re: Solve-left for systems over CDF/RDF
On 2/17/11 7:08 PM, Rob Beezer wrote: Or: "Do you know your left from your right?" Or: "Not for those with dyslexic tendencies" [Ed. e.g. me] sage: A = matrix(QQ,[[1,2],[3,4]]) sage: A.solve_left(vector(QQ,[1,1])) (-1/2, 1/2) sage: A.solve_right(vector(QQ,[1,1])) (-1, 1) sage: B = matrix(RDF,[[1,2],[3,4]]) sage: B.solve_left(vector(RDF,[1,1])) (-1.0, 1.0) sage: B.solve_right(vector(RDF,[1,1])) (-1.0, 1.0) In almost every case in the linear algebra routines (systems, eigenvalues, kernels) "left" and "right" refer to where a vector goes in the appropriate product of a matrix with a vector. So for A above, the left and right refer to where the vector of unknowns goes (x*A=b, A*x=b). It appears that for matrices over RDF and CDF, the solve_right command is using totally general code, with the vector of unknowns on the right of the matrix. The solve_left command specifically for RDF and CDF appears to have identical functionality, acting contrary to the naming conventions elsewhere. Any objections to renaming the solve_left for RDF and CDF to solve_right, and perhaps adding a proper solve_left for RDF/CDF? So I guess you're volunteering to fix #7852 and possibly #4932? Hooray! Jason -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Re: Rapid growth in Python popularity
On Fri, Feb 18, 2011 at 8:36 AM, rjf wrote: > Many people using Matlab are, I think, using it within some > organization > such as a college or an engineering lab. The incremental cost for one > more Matlab user license is small and probably part of the overhead of > the organization, and so there is no apparent cost to the individual > user. This has the very significant advantage (to me) that it is > free (as in free beer). The problem with Sage by comparison is that > it is free (as in free press) but has significant overhead for the > first person to try to install it somewhere, (apparently still, > especially on Windows...) But again that is another story. At University of Washington, even with a site license, MATLAB costs me $100, so I don't have it on my laptop. There are limited licenses for students, and I've been told they have trouble doing homework assignments, due to sharing those licenses. In my experience, installing MATLAB is much more difficult than installing Sage.I can imagine no worse hell than being asked to install a working MATLAB on a bunch of random Linux, OS X, and Windows boxes. >> > I am not surprised that there is a relatively small overlap between >> > scientific >> > computing and Python programming. Most scientific computing tasks are >> > sensitive >> > to efficiency of resulting code. >> >> This is just FUD, suggesting that one can't use Python for scientific >> computing due to it being too slow. > > Well, the issue is not so much the programming language efficiency, > or how much it matters in practice to have some data setup and web > access > and debugging be written in a friendlier languaage, but a perception. Thus your FUD is all the more damaging >> Most people doing scientific also >> use C/Fortran-based libraries such as numpy and scipy, and quite a few >> use Cython as well. > > Can't those libraries (or something like them) also be called from C > or Fortran? If those libraries = "numpy/scipy", then absolutely not. Most of the code in numpy is new code, which provides a different and powerful perspective on n-dimensional data manipulation that isn't provided by any underlying library it depends on (BLAS). Some of scipy is just wrapping Fortran libraries, and some (quite a bit) is new code not wrapping anything. -- William -- William Stein Professor of Mathematics University of Washington http://wstein.org -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Re: Rapid growth in Python popularity
Hi Python's barrier-to-entry is the lowest of all the languages under discussion (in terms of time to learn it). It is easier to enforce good coding style because much of it is already integrated with the language... e.g. indented control structures & loops. Optimizing-python-with-calling-other-languages-or-cython even has arguably a lower barrier-to-entry than the other languages under discussion. Prototyping is much faster in python. So often 'runtime' debates do not have a holistic comprehensive view of scientific computation. Include prototyping time and coding and polishing and maintenance time, and both the time and cost in $$ is much lest. Some applications are maintained over years and many postgrad slaves^H^H^H^H students. A research group can train a new member in python code quickly. The python community is huge, skills are available, and often the needs are not in the core science algorithm which is well looked after, but in the glue and interface, which requires a less in-depth understanding of the science than the core algorithm. It allows non-niche programmers to assist more easily than... FORTRAN. I guess you can tell which side of the fence I am currently on ;) Regards, Jan -- .~. /V\ Jan Groenewald /( )\www.aims.ac.za ^^-^^ -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] Re: Rapid growth in Python popularity
On Feb 18, 7:31 am, William Stein wrote: > On Thu, Feb 17, 2011 at 9:11 PM, rjf wrote: > > > On Feb 17, 4:49 pm, Matt Goodman wrote: > >> MATLAB isn't a tool used outside of academia very often. > > > I think you are wrong here. I don't have any data to point to though. > > Do you have any data on this? > > No data versus no data. > > >> Its licensing makes it hard to redistribute code (like to a third party), > >> or even run it on a couple different workstations in a HPC sense. > > > Huh? How so? You write a program, you own it, you can give it to > > someone else. > > Did they make that hard to do somehow? > > Each copy of MATLAB costs (a lot of) money. Python is free. (It's > simply amazing to me that you don't realize that this is what he is > talking about! How is it even possible?) Ah, I see. My misunderstanding was in taking Matt's statement at its face. We agree that it is no problem to (re)distribute code that you write to anyone else. The recipient of the code would either have to have a Matlab licensed system or a system that ran Matlab code, like Octave [sort of]. So my assumption is that anyone who was interested in your own coded Matlab program either had such a setup, or was only interested in looking at the code, not running it. This latter situation is not that unusual, I think. I have occasionally looked at Matlab programs to learn from them. Usually it is harder to figure out than I expected, but that's another story. I think that if Matt is objecting to the difficulty in giving someone else a completely working system written in the Matlab language including Matlab in a form that it can be redistributed without restriction, that is another issue. Of course a program written using Sage cannot be redistributed without restriction either. The GPL is a restriction. But again that is another story. Many people using Matlab are, I think, using it within some organization such as a college or an engineering lab. The incremental cost for one more Matlab user license is small and probably part of the overhead of the organization, and so there is no apparent cost to the individual user. This has the very significant advantage (to me) that it is free (as in free beer). The problem with Sage by comparison is that it is free (as in free press) but has significant overhead for the first person to try to install it somewhere, (apparently still, especially on Windows...) But again that is another story. > > >> I > >> would guess the matlab base is about 2x the scientific python community, > >> but > >> the science python people are only 5%-10% of Python users. The same foes > >> for LabView etc. > > > I think you are way off, and the Matlab community is many times the > > scientific > > python community, but again I have no data. > > The TIOBE index also illustrates is that whatever the real data is, it > is probably constantly changing, and in some cases changing very > quickly. See, e.g., the history of Objective-C in TIOBE -- 3 years > ago it was a very unpopular language, and now it is very popular > (probably because of Apple's iOS programming). > > > I suspect that the > > serious scientific computing community is almost all non-python, and > > that > > it consists of C/Fortran/Matlab. > > I suspect that was a true statement at some point in time. I would even speculate that the proportion of Python users has increased infinitely from some point in time, say 1950. What is taught to engineers at UW? a google search on university washington engineering python gets 98,000 hits.with matlab it gets 124,000 hits. At UC Berkeley, 148,000 vs 158,000. Python IS taught in some intro classes here Now if we remove the term "engineering" from the search, there are more hits, and at UC, python > matlab. Some of this is scientific computing of some sort, but probably most of it is not. > > > > >> Its easy to forget that science Python is a serious _minority_ in the > >> Python > >> community. I attend the Enthought monthly Python meetup here in Austin, > >> and > >> of 50 people, maybe 3-5 are science Python programmers. > > > I am not surprised that there is a relatively small overlap between > > scientific > > computing and Python programming. Most scientific computing tasks are > > sensitive > > to efficiency of resulting code. > > This is just FUD, suggesting that one can't use Python for scientific > computing due to it being too slow. Well, the issue is not so much the programming language efficiency, or how much it matters in practice to have some data setup and web access and debugging be written in a friendlier languaage, but a perception. For the last umpteen years it was possible to write programs in some convenient interactive --but possibly slower than optimized-compiled-Fortran -- language. Which language doesn't really matter. It could be Perl, TCL, even Lisp, The perception by (some, in the past, almost all) heavy users of scientific
[sage-devel] Series expansion.
Hi everyone!
I'd like to know if there is a way of finding the series expansion of a
given function around zero and infinity, Is it possible?
I tried with sympy.series, didn't work
sage: reset()
sage: from sympy import *
sage: r = Symbol('r')
sage: sympy.series(2*r/sinh(2*r), r)
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Re: [sage-devel] Re: Rapid growth in Python popularity
On Thu, Feb 17, 2011 at 9:11 PM, rjf wrote: > > > On Feb 17, 4:49 pm, Matt Goodman wrote: >> MATLAB isn't a tool used outside of academia very often. > > I think you are wrong here. I don't have any data to point to though. > Do you have any data on this? No data versus no data. >> Its licensing makes it hard to redistribute code (like to a third party), >> or even run it on a couple different workstations in a HPC sense. > > Huh? How so? You write a program, you own it, you can give it to > someone else. > Did they make that hard to do somehow? Each copy of MATLAB costs (a lot of) money. Python is free. (It's simply amazing to me that you don't realize that this is what he is talking about! How is it even possible?) >> I >> would guess the matlab base is about 2x the scientific python community, but >> the science python people are only 5%-10% of Python users. The same foes >> for LabView etc. > > I think you are way off, and the Matlab community is many times the > scientific > python community, but again I have no data. The TIOBE index also illustrates is that whatever the real data is, it is probably constantly changing, and in some cases changing very quickly. See, e.g., the history of Objective-C in TIOBE -- 3 years ago it was a very unpopular language, and now it is very popular (probably because of Apple's iOS programming). > I suspect that the > serious scientific computing community is almost all non-python, and > that > it consists of C/Fortran/Matlab. I suspect that was a true statement at some point in time. >> >> Its easy to forget that science Python is a serious _minority_ in the Python >> community. I attend the Enthought monthly Python meetup here in Austin, and >> of 50 people, maybe 3-5 are science Python programmers. > > I am not surprised that there is a relatively small overlap between > scientific > computing and Python programming. Most scientific computing tasks are > sensitive > to efficiency of resulting code. This is just FUD, suggesting that one can't use Python for scientific computing due to it being too slow. Most people doing scientific also use C/Fortran-based libraries such as numpy and scipy, and quite a few use Cython as well. These tools allow you to write code that is as fast as code one produces in Matlab or Fortran. -- William > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- William Stein Professor of Mathematics University of Washington http://wstein.org -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Patchbot and alpha versions
+1 that would make much sense from a development perspective On Friday, February 18, 2011 2:28:31 PM UTC, Jeroen Demeyer wrote: > > Why not *only* the latest alpha? That would make more sense to me. > > -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Patchbot and alpha versions
On 2011-02-18 14:57, Simon King wrote: > I could imagine that it would not be feasible to let the patchbot > operate with a multitude of different sage versions. But perhaps it > would be doable to let it work with *two* versions: 1. the latest > release (default), 2. the latest alpha version. Why not *only* the latest alpha? That would make more sense to me. Jeroen. -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Rational polynomials via FLINT (#4000)
On 01/29/10 01:08 AM, Alex Ghitza wrote: On Thu, 28 Jan 2010 15:52:23 -0800 (PST), Sebastian Pancratz wrote: After reviving the work from last September/ October with some significant help of Mike Hansen at Sage Days 19 a week ago, we finally had a version of the patch that applied cleanly to 4.3.1.rc0 (plus the three patches by Robert Bradshaw from #383) and, at least on my machine and another departmental machine, passed all doctests. However, when Alex Ghitza had a look at this, he noticed a doctest failure with his setup. It turns out that he can already produce an error with the commands sage: R. = QQ[] sage: f = 3/2*x - 1/3 sage: %time _ = f % f Error: unable to alloc/realloc memory This is on 32-bit Arch Linux, with gcc 4.4.2. I believe it is a 32-bit problem, because I'm not seeing the failure on 64-bit Arch Linux with the same gcc version. By the way, if anyone wants access to the machine in question for debugging purposes, that can be arranged by emailing me offlist. Best, Alex It's not simply 32-bit issue, as my OpenSolaris system builds binaries by default to 32-bit. (A 64-bit version of Sage on Solaris is some way off). However, I don't see this issue: sage: R. = QQ[] sage: f = 3/2*x - 1/3 sage: %time _ = f % f CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s Wall time: 0.00 s sage: on my 32-bit build on OpenSolaris. It might be specific to 32-bit ArchLinux of course. Dave -- A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? Dave -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
Re: [sage-devel] Patchbot and ticket comments
On 2011-02-18 00:27, Robert Bradshaw wrote: >> 2) The ticket description can be *edited*, comments not. For example, >> if some comments just mention a new spkg, then the patchbot will >> automatically think it's a dependency, even when it's not. > > Again, I see this as a disadvantage, because then there's no history > or ordering to look at. So how do I convince the patchbot that the spkgs mentioned in #2329 aren't actually dependencies? -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] Patchbot and alpha versions
Hi! It seems to me that the patchbot refuses quite a number of patches since apparently it tries to apply the patches to the latest release of Sage. But I, for one, often produce my patches on top of a recent alpha version of the forthcoming release. I could imagine that it would not be feasible to let the patchbot operate with a multitude of different sage versions. But perhaps it would be doable to let it work with *two* versions: 1. the latest release (default), 2. the latest alpha version. For example, Apply abc.patch xyz.patch would make the patchbot apply the two patches to the latest release, whereas with Apply abc.patch xyz.patch to alpha it would start with the latest alpha. Could that work? Cheers, Simon -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] Re: vtk
There is an experimental spkg for vtk. But I think it needs some serious updating; last time I tired it, it did not compile on my machine. Though you might want to give it a try. sage: experimental_packages() ([], ['4ti2.p0', 'PyQt4-4.6.2', 'PyVTK-0.4.74', 'QScintilla2-2.4', 'asymptote-1.29', 'bison-2.3', 'boost_1_34_1', 'brian-1.2.1.p0', 'cadabra-0.115', 'chomp-20100213.p2', 'clapack-3.6', 'clisp-2.43', 'cmake-2.4.8', 'dvipng-1.8', 'ets-3.1.1.rev23241', 'flex-2.5.33', 'fortran-OSX64-20090120', 'frobby-0.7.6', 'gcc-4.2.1', 'gnofract4d-3.6', 'gnuplot-4.0.0', 'jmol-11.5.2-src-v2', 'libcprops-0.1.6', 'libjpeg-6b', 'libsigsegv-2.2', 'macaulay2-1.1-r7221.p0', 'mayavi_2.2.1', 'meataxe-2.4.3', 'modglue-1.8', 'mpich2-1.0.5', 'numarray-1.5.2', 'numeric-24.2', 'openopt-0.29', 'pcre-6.5', 'pexpect-2.1', 'phcpack-2.3.21', 'polymake-2.2.p5', 'processing-0.52', 'pygame-1.7.1release', 'pygsl-0.3', 'pygtk-2.8.4', 'pynifti-p0', 'pyqt-3.15.1', 'pyrexembed-0.1.1-20060517', 'python-unladen-2009Q2', 'qasm-1.4', 'qepcad-1.50', 'quantlib-0.9.6', 'quantlib_swig-0.9.6', 'reallib3-linux-20060728', 'sandpile-1.51', 'scitools++', 'simpqs-20061128b', 'sip-4.9.3', 'soya-0.11.2.p0', 'soya_cvs-2006.05.09', 'superlu-3.0', 'surf-1.1', 'vtk_meta-1', 'wxPython-2.8.7.1', 'yafray-0.0.9', 'yassl-1.4.0']) On Friday, February 18, 2011 12:34:44 PM UTC, Mag wrote: > > Has anyone compiled VTK, http://www.vtk.org/, into sage? I would like > to compile this but would need some assistance and/or tips. > -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
[sage-devel] vtk
Has anyone compiled VTK, http://www.vtk.org/, into sage? I would like to compile this but would need some assistance and/or tips. -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
