From: nma@12000.org   
      
   On 2/22/2018 1:24 PM, clicliclic@freenet.de wrote:   
   >   
   > "Nasser M. Abbasi" schrieb:   
   >>   
   >> On 2/22/2018 7:57 AM, clicliclic@freenet.de wrote:   
   >>>   
   >>> "Nasser M. Abbasi" schrieb:   
   >>>>   
   >>>> How high a number "n" can your cas integrate this?   
   >>>>   
   >>>>           1/((1 + x^n)*(1 + x^2))   
   >>>>   
   >>>> Fricas 1.3.2 and Rubi 4.14.7 go up to n=18. Then after that, they   
   >>>> return unevaluated.   
   >>>>   
   >>>> Mathematica gives an answer for higher than 18, but the result after   
   >>>> 18 is in terms of Root objects. I tried up to n=100.   
   >>>>   
   >>>> Maple also can go higher than n=18, and it also gives results   
   >>>> in terms of RootOf. Tried up to n=200. So to remove these Roots, one   
   >>>> has to evaluate the answer numerically.  I assume this is why Rubi and   
   >>>> Fricas stop at n=18.   
   >>>>   
   >>>> Any insight why 18 is the limit here? Is it due to some   
   >>>> factorization done, which after n=18 produces polynomials that   
   >>>> can't be solved exactly for higher order?   
   >>>>   
   >>   
   >> [...]   
   >>   
   >> Sorry, let me clarify things again. FriCAS hangs at n=29.   
   >> I have it running for one hr now at n=29. Will leave it   
   >> running and will check on it after I come back from school.   
   >>   
   >> Here is what I found:   
   >> ======================   
   >> Rubi:  Up to n=18 OK, then unevaluated after n=18.   
   >> Maple: Up to n=18 OK, then uses ROOT objects for n>18. Tried to 200   
   >> Mathematica: Up to n=18 OK, then uses ROOT objects for n>18. Tried to 100   
   >> FriCAS: Up to n=28 OK, then "hangs" or still trying.....   
   >>   
   >> So the winner so far is FriCAS on this test, it does it   
   >> for n=28, with no root objects. root objects can only be   
   >> evaluated numerically to get rid of them.   
   >>   
   >   
      
   > I am glad to learn that the super-massive FriCAS bug has vanished at a   
   > second glance! In fact, I see no problem here at all. While it remains   
   > uncertain how long the computation for n=29 takes, this is likely to   
   > happen for some power anyway ...   
   >   
   > Martin.   
   >   
      
   Yes, sorry, I must have mixed it up with 1/((1 + x^n)*(1 + x^2))   
   for `n` being symbolic (no numerical value). In this call,   
   all CAS systems return unevaluated.   
      
   I like to also report that Fricas finally gave answer for n=29.   
   many pages long. But it did not hang.   
      
   good job Fricas.   
      
   --Nasser   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)