Re: [sage-support] Re: Simplifying expressions involving sums

2014-04-03 Thread Luigi Malagò
thanks for your reply nils,
any other suggestion about what i could do to help maxima in simplifying
my expression?
in the end it does not complicated to me, it's just a problem of factoring
out thing.. ;-P

PS: also a pointer to other software packages besides maxima that would
help me would be appreciated

regards,
luigi


On Thu, Apr 3, 2014 at 8:05 PM, Nils Bruin nbr...@sfu.ca wrote:

 On Thursday, April 3, 2014 10:23:54 AM UTC-7, Luigi Malagò wrote:

 PS: maxima.load('simplify_sum') didnt work


 In order for it to affect the sum command, you'd need to do
 maxima_calculus.load('simplify_sum') and then some work is required to
 actually call the routine on your expression. However, I think sage already
 loads simplify_sum and probably calls it in the process of processing a
 sum. It just looks like maxima doesn't simplify your expression further:

 (%i1) load(simplify_sum);
 (%o1)
 /usr/local/sage/sage-git/local/share/maxima/5.29.1/share/solve_rec/simpl\
 ify_sum.mac
 (%i2) display2d:false;

 (%o2) false
 (%i3) S : 1/2* alpha * sum(exp(-alpha/3*j)*alpha *
 sum(exp(-alpha/2*i)*exp(-alpha*((t-i-j)-1-i)),i,0,(t-1-j)-1),j,0,t-1);

 (%o3)
 alpha^2*('sum(%e^-(alpha*j/3)*'sum(%e^(-alpha*(t-j-2*i-1)-alpha*i/2),i,
  0,t-j-2),j,0,t-1))
  /2
 (%i4) simplify_sum(S);

 (%o4)
 alpha^2*('sum((%e^(3*alpha*(t-j-1)/2)-1)*%e^(-alpha*t+2*alpha*j/3+alpha)
  /(%e^(3*alpha/2)-1),j,0,t-1))
  /2

 and I don't think sage tries anything beyond what maxima does.

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Re: [sage-support] Re: Simplifying expressions involving sums

2014-04-03 Thread Nils Bruin
On Thursday, April 3, 2014 11:09:12 AM UTC-7, Luigi Malagò wrote:

 PS: also a pointer to other software packages besides maxima that would 
 help me would be appreciated

Free beer solution: www.wolframalpha.com does it (i.e., mathematica 
simplifies the sums away)
maple does too.

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