N[] MachinePrecision vs. Arbitrary Precision
- To: mathgroup at smc.vnet.net
- Subject: [mg118415] N[] MachinePrecision vs. Arbitrary Precision
- From: Rafael Dunn <worthless.trash.junk at gmail.com>
- Date: Wed, 27 Apr 2011 05:39:25 -0400 (EDT)
Mathematica 8.0.1.0, Mac OSX x86 In:= N[Sin[Exp[100]]] N[Sin[Exp[100]], 1] N[Sin[Exp[100]], 11] Out:= -0.999105 0.1 0.14219812366 I realize that N[exp] = N[exp, MachinePrecision]. This indicates when N[] is asked to calculate to MachinePrecision, it produces an incorrect result in this example. However, when I use N[exp,n] where n < MachinePrecision, I get a correct output. Is this because N[exp,n] uses ExtraPrecision, while N[exp] does not? If I set MaxExtraPrecision = 0, then N[exp,n] produces a result of 0 with the note that there are no significant digits to display until I have made n high enough for Mathematica to be able to internally compute it.