Re: Numerical accuracy/precision - this is a bug or a feature?

*To*: mathgroup at smc.vnet.net*Subject*: [mg120012] Re: Numerical accuracy/precision - this is a bug or a feature?*From*: Richard Fateman <fateman at cs.berkeley.edu>*Date*: Tue, 5 Jul 2011 05:11:22 -0400 (EDT)*References*: <ius5op$2g7$1@smc.vnet.net> <ius7hm$358$1@smc.vnet.net>

In brief: yes to both. On 7/4/2011 4:18 AM, Kevin J. McCann wrote: ... >> >> 1. N[2.0,20] should give 2 with accuracy/precision/whatsever about 20 >> decimal digits, i.e. 2.00000000000000000000 > WRI will defend this as a feature. You thought that the semantics of N[] were the same as SetPrecision e.g. N[SetPrecision[2.0, 20]*N[Sqrt[2], 20], 20] works as you expected. So from your perspective, and from the perspective of anyone else who thinks along the same lines, it is a bug. I would prefer to call it a design error. 2.0 (indeed, any floating point number) is a perfectly respectable way of denoting a number that can be expressed in higher precision by adding binary zeros. WRI doesn't agree. RJF