Re: For loop problem in mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg90221] Re: For loop problem in mathematica*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Wed, 2 Jul 2008 05:33:30 -0400 (EDT)*Organization*: Uni Leipzig*References*: <g4d2qf$emo$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, Mathematica does what *you* want, and *if* you wish tho get exact results and later use N[_,25] you have to live with the very long number you create. Look what (i = 1; Nest[# + 1/(i++)^2 &, 0, 100] Sqrt[6*x]) // Timing gives. You mean (i = 1; Nest[# + 1/(i++)^2 &, N[0, 25], 100000] N[Sqrt[6*x], 25]) // Timing to avoid the infinite precision calculation. But it will still be very slow. Regards Jens PhysNova wrote: > Hi, > i wrote a simple program of evaluating Pi number in M6 to test cpu > computation timing, to do this a simple for loop > > was used: > > x=0;For[i = 1, i < 10,000,000, i++, x = x + 1/(i^2)];N[Sqrt(6*x),25]// > Timing > > the result was catastrophe! it take few minuates. but i first expect > to do this very simple job in few > > seconds.computation time is just satisfactory up to 100000 cycle. > > could anyone interperet this falut? > our get an idea to improve the result? > > Tanks >