Min-MaxPrecision?

*To*: mathgroup at smc.vnet.net*Subject*: [mg115718] Min-MaxPrecision?*From*: Marco Masi <marco.masi at ymail.com>*Date*: Wed, 19 Jan 2011 05:25:57 -0500 (EST)

I would like to run a program that makes always quad precison calculations in all variables. I thought Mathematica would do that internally by setting $MinPrecision = $MaxPrecision = nrd, with nrd the number of digits. However, if I try $MinPrecision = $MaxPrecision = 32; var = 1 - 0.0000000000000000000000000000001; N[var, 32] I get 1. Whereas I expected 0.9999999999999999999999999999999 Block seems to do the job. In fact Block[{$MinPrecision = 32, $MaxPrecision = 32}, 1 - 0.00000000000000000000000000000001`32] gives 0.99999999999999999999999999999999. But that's not very useful in my case because I would like to run a long program and can't apply it on all variables. Ideally I need something like Block[{$MinPrecision = 32, $MaxPrecision = 32}, ....... var in long program with zillions of calculations.....] And after execution know what exactly var is to 32 digits precision and Exporting it to file with that precision. If I type var, or N[var,32] it will output only with the default 15 digits. Export will consequently do the same. Can anyone help? Marco.