[sage-support] Computing the Galois group of a degree 12 polynomial

2010-09-07 Thread pgdoyle
I tried using Sage to compute the Galois group of a polynomial of degree 12, using the following code: p= -98298717579910546875000 + 36091888356881423583984375* x - 1193313058398713452148437500* x^2 + 754759543928715527343750* x^3 + 1582754650853547656250* x^4 -

[sage-support] Re: Taylor series of a matrix

2008-02-02 Thread pgdoyle
On Feb 1, 8:59 am, William Stein [EMAIL PROTECTED] wrote: On Jan 31, 2008 7:59 AM, pgdoyle [EMAIL PROTECTED] wrote: On Jan 31, 12:29 am, William Stein [EMAIL PROTECTED] wrote: On Jan 30, 2008 3:48 PM, pgdoyle [EMAIL PROTECTED] wrote: I would like to take the Taylor series

[sage-support] Re: Taylor series of a matrix

2008-01-31 Thread pgdoyle
On Jan 31, 12:29 am, William Stein [EMAIL PROTECTED] wrote: On Jan 30, 2008 3:48 PM, pgdoyle [EMAIL PROTECTED] wrote: I would like to take the Taylor series of a matrix. But I find I can't even put a Taylor polynomial into a matrix without its being simplified. sage: f=-x/(2*x-4

[sage-support] Re: Taylor series of a matrix

2008-01-31 Thread pgdoyle
On Jan 31, 8:05 am, John Cremona [EMAIL PROTECTED] wrote: You could try substituting x+1 for x first, then do what you want, and substitute back at the end, I would expect the auto-simplification to happen at that last step too, but you would be able to (say) replace x by (x-1) in the

[sage-support] Taylor series of a matrix

2008-01-30 Thread pgdoyle
I would like to take the Taylor series of a matrix. But I find I can't even put a Taylor polynomial into a matrix without its being simplified. sage: f=-x/(2*x-4); f -x/(2*x - 4) sage: g=taylor(f,x,1,1); g 1/2 + x - 1 sage: matrix(1,[g]) [x - 1/2] sage: m=matrix(1,[f]); m [-x/(2*x - 4)] sage:

[sage-support] Re: int / Integer question

2008-01-23 Thread pgdoyle
On Jan 22, 2:17 pm, Carl Witty [EMAIL PROTECTED] wrote: 'Integer' is a Sage type. This means it has lots of useful mathematical convenience methods (like .is_square()), it participates in the coercion model, etc. Also, 'Integer' is implemented with GMP, and 'long' is not, so 'Integer' is

[sage-support] Re: Symbolic computation is slow

2007-12-31 Thread pgdoyle
sage: var(x) x sage: time sum(((x+sin(i))/x+(x-sin(i))/x).rational_simplify() for i in xrange(100)) 200 CPU time: 5.29 s,  Wall time: 39.10 s sage: time maxima('sum(ratsimp((x+sin(i))/x+(x-sin(i))/x),i,1,100)') 200 CPU time: 0.02 s,  Wall time: 0.55 s Those times above are

[sage-support] Display of polynomials

2007-12-31 Thread pgdoyle
The following behavior is not what I want or expect for the ordering of terms when Sage displays a polynomial: sage: 1-x 1 - x sage: 1+x x + 1 sage: 1-x^2 1 - x^2 sage: 1+x^2 x^2 + 1 sage: 1+x-x^2 -x^2 + x + 1 sage: 1+x+x^2 x^2 + x + 1 Is there some way to let Sage know that I'd prefer a

[sage-support] Symbolic computation is slow

2007-12-27 Thread pgdoyle
I'm having problems doing symbolic computations in Sage. Calls to rational_simplify() seem to take about .2 seconds each. Working directly in Maxima is about 100 times faster. Mathematica is something like 500 times faster. In Sage, where does the time go? Is there something I can do right

[sage-support] Re: Sage notebook: Changes not saved in Sage 2.9

2007-12-23 Thread pgdoyle
That said, I *do* want to change the implementation so that any time a cell is changed and the cursor leaves the cell or save close is clicked, the changed version is sent back to the server.  I think Tom Boothby has argued against this, which is why it hasn't happened already. I think it

[sage-support] How many times should you shuffle a deck of cards?

2007-12-22 Thread pgdoyle
I'm looking for advice about how to speed up the attached Sage program. I've been commissioned to write an article for a popular math journal debunking the notion that `seven shuffles suffice'. This article will feature a computation done in Sage of the exact probability of winning `New Age

[sage-support] Re: Sage notebook: Changes not saved in Sage 2.9

2007-12-22 Thread pgdoyle
On Dec 18, 12:51 pm, pgdoyle [EMAIL PROTECTED] wrote: Changes to my Sage notebooks are not always getting saved.  I'm running Sage 2.9 from Firefox 2.0.0.11 on Mac OS 10.4.11 on a PowerMac G5. I've tried this now on with Safari instead of Firefox, and on a Linux box instead of the Mac

[sage-support] Sage notebook: Changes not saved in Sage 2.9

2007-12-18 Thread pgdoyle
Changes to my Sage notebooks are not always getting saved. I'm running Sage 2.9 from Firefox 2.0.0.11 on Mac OS 10.4.11 on a PowerMac G5. Simplest case: If I fire up a new worksheet, enter 2+2, then `Save and Close', when I reopen the worksheet, it's empty. If I fire up a new worksheet, enter

[sage-support] Display of free module element is funny

2007-12-13 Thread pgdoyle
The vector v2 doesn't display properly in the attached Sage output. Or rather, the free module element v2. (Should I be worried that I got a free module element when I expected a vector, or will everything work out for the best?) Cheers, Peter --- sage:

[sage-support] Re: Subcontracting to Mathematica

2007-12-13 Thread pgdoyle
Let me simplify the question. Is there a better way to get Mathematica to go off and compute a Bessel function for me than this: def math_bessel_K(nu,x): m=mathematica('N[BesselK['+str(mathematica(nu)) +','+str(mathematica(x))+'],20]') return m.sage() Cheers, Peter

[sage-support] Re: Bessel argument order

2007-12-12 Thread pgdoyle
To get back to the question of argument order, it seems strange to me that pari(2).besselk(3) should meant K_2(3) rather than K_3(2). sage: pari(2).besselk(3) 0.06151045847174203765682007145 sage: bessel_K(2,3) 0.0615104584717420 bessel_K(nu,x) is written K_nu(x) because the first argument nu

[sage-support] Subcontracting to Mathematica

2007-12-12 Thread pgdoyle
Say I want to get Mathematica to compute some function that Sage can't compute for me. What is the best way to pipe the arguments into Mathematica, and then get the answer back into the world of sage? Here's what I tried: sage: def math_bessel_K(nu,x): ...

[sage-support] Plotting in sage versus plotting in matlab

2007-12-08 Thread pgdoyle
I told a colleague about sage, wondering if he would see it as a viable alternative to matlab for numerical work. This was his response: I don't know SAGE - it looks great. I'm looking forward to trying it once things settle down. I've used python for a project and it was excellent. I think

[sage-support] Re: Weaning

2007-12-07 Thread pgdoyle
In[7]:= Pi + E // N + 5 // N Out[7]= (5. + N)[5.85987] Gees -- what in the heck does (5. + N)[5.85987] mean? It means 5.+N applied to 5.85987. (In Mathematica f[x] is how you would express applying f to x). And here's why: In[8]:= a+b//c+d//e Out[8]= e[(c + d)[a + b]] So Pi + E // N

[sage-support] Re: Weaning

2007-12-07 Thread pgdoyle
On Dec 7, 10:17 pm, Mike Hansen [EMAIL PROTECTED] wrote: I think what confusing is the following: In[1]:= Pi // N Out[1]= 3.14159 In[2]:= Pi // N + 2 Out[2]= (2 + N)[Pi] What does it mean in Mathematica to add 2 to N? Does it just treat N as a formal symbol when you add 2 to it N?

[sage-support] Re: Weaning

2007-12-07 Thread pgdoyle
Mike, Thanks for the help - much appreciated! On Dec 3, 9:30 pm, Mike Hansen [EMAIL PROTECTED] wrote: If you just need to substitute, you can do: sage: m.subs(x=1) [-1 -1] [-1 0] If you want to apply a more general map to the coefficients, then you can do: sage: m.apply_map(lambda

[sage-support] Weaning

2007-12-03 Thread pgdoyle
I'm trying to wean myself from Mathematica. Here are some issues I've been wrestling over with SAGE. I apologize in advance for not showing the sage output, which I'm sure there is some easy way to generate automatically from this file. 1) Taylor series of a rational function. This works: