Re: Mathematica bugs?
- To: mathgroup at smc.vnet.net
- Subject: [mg67320] Re: [mg67301] Mathematica bugs?
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sun, 18 Jun 2006 05:13:11 -0400 (EDT)
- Reply-to: hanlonr at cox.net
- Sender: owner-wri-mathgroup at wolfram.com
You need to use greater precision than machine precision x = Pi/4; For[i = 0, i < 56, i += 1, x = 2*Abs[x - 1/2]]; x//Simplify N[x,20] 56593902016227523 - 18014398509481984*Pi 0.79387245267980382900 x=Nest[2*Abs[#-1/2]&, Pi/4, 56]//Simplify N[x,20] 56593902016227523 - 18014398509481984*Pi 0.79387245267980382900 x = Pi/4; For[i = 0, i < 50, i += 1, x = 2*Abs[x - 1/2]]; N[Log[x],20] -3.3676443458316025909 x=Nest[2*Abs[#-1/2]&, Pi/4, 50]; N[Log[x],20] -3.3676443458316025909 Bob Hanlon ---- Yaroslav Bulatov <yaroslavvb at gmail.com> wrote: > When I run the following line > x = Pi/4; For[i = 0, i < 56, i += 1, x = 2*Abs[x - 1/2]]; N[x] > I get > 3. > > But x should always stay between 0 and 1, why do I get 3? > > Also > x = Pi/4; For[i = 0, i < 50, i += 1, x = 2*Abs[x - 1/2]]; N[Log[x]] > gives me > Indeterminate > > How can I get an indeterminate here? >