Re: "Sloppy Union"? (Union of a list with *nearly* equ
- To: mathgroup at smc.vnet.net
- Subject: [mg42171] Re: "Sloppy Union"? (Union of a list with *nearly* equ
- From: Bill Rowe <listuser at earthlink.net>
- Date: Sat, 21 Jun 2003 02:49:45 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On 6/20/03 at 4:57 AM, siegman at stanford.edu (AES/newspost) wrote: > Still don't grasp, however, what SetPrecision with *reduced* precision > really does, or for what purpose it might be used? For example, > SetPrecision[Pi,3] --> 3.14 > Cos[y] --> -1.0 > 1 + y -> 4.14159 > Is it nothing more that a "print wrapper" for y, and nothing else? No, it isn't a "print wrapper" for y at all. It defines the precision of y to be 3. Try the following. Precision[Cos@y] which results in 5.0057 in version 5.0 Precision[1 + y] which results in 3.12002 in version 5.0 Contrast this with Precision[Cos@Pi] which results in Infinity or Precison[1 + Pi] which results in Infinity Note some versions of Mathematica default to displaying 6 digits for any number with a precision less than or equal to $MachinePrecision. It appears this as changed in version 5.0. I've only just started using version 5.0 and I am not yet familiar with many of the changes that have been made.