Re: Conversion to atomic units
- To: mathgroup at smc.vnet.net
- Subject: [mg17546] Re: [mg17448] Conversion to atomic units
- From: "David Park" <djmp at earthlink.net>
- Date: Fri, 14 May 1999 01:13:13 -0400
- Sender: owner-wri-mathgroup at wolfram.com
>Does anyone know whether a package is available somewhere on the >internet that converts quantities from SI (or CGS) units to atomic >units? If not, does anyone have suggestions concerning an approach to >writing such a package? Any information or advice would be gratefully >apreciated! >Cheers, >michael >Prof. Michael A. Morrison >Dept. Physics & Astronomy >University of Oklahoma Michael, I have a package called ExtendUnits which is available at my web site. It extends the standard package Miscellaneous`Units`. It will automatically convert a wider class of expressions (such as root expressions), allows specification of output format at the same time, introduces a new PrefixForm which automatically prepends correct prefixes, allows conversion to multiple compatible units at once, or allows parsing to compatible descending units and allows expressions to be deunitised in a controlled manner with implied units for use in plotting or numerical work. Since seeing your request I have been spurred on to add a supplementary package, ReducedUnits, which I believe will serve your purpose. It allows a reduced unit system to be established by specifying a set of physical constants which will be set to 1, and a complementary set of retained base SI units. Once the system is established the units in the any expression can be converted to reduced units. In addition a unit can be converted to any other unit if they are related by an exponentiated product of the physical constants. It can be used, for example, to implement geometrized units used in relativity or atomic units. David Park djmp at earthlink.net http://home.earthlink.net/~djmp/