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: <firstname.lastname@example.org> <email@example.com>
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, 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