Re: Table through zero...strange

*To*: mathgroup at smc.vnet.net*Subject*: [mg67037] Re: Table through zero...strange*From*: David Bailey <dave at Remove_Thisdbailey.co.uk>*Date*: Wed, 7 Jun 2006 05:10:30 -0400 (EDT)*References*: <e63mqt$kqd$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

leptonic wrote: > Hello, > > When i type in Mathematica (version 4) Table[x, {x, -0.1, 0, 0.02}] > > it gives me {-0.1, -0.08, -0.06, -0.04, -0.02, -3.46945 x 10-18]} > but for example Table[x, {x, -0.1, 0, 0.05}] will give a reasonable > {-0.1, -0.05, 0.}. > > Probably a very stupid question but i can't figure out why the zero > makes problem. > > Thanks for any help. > Floating point numbers are usually not exact - so this result is not surprising. In fact, by default floating point numbers are stored at machine precision using 64-bit floating point. This is a binary format, so numbers that are not of the form a*2^n (a and n integer) can never be exact. The following is a more reliable way to specify such an iteration: Table[x/100.,{x,-10,0,2}] David Bailey http://www.dbaileyconsultancy.co.uk