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Topic: Engineering requests
Replies: 14   Last Post: Mar 14, 2012 1:38 AM

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 Daniel Lichtblau Posts: 1,761 Registered: 12/7/04
Re: Engineering requests
Posted: Mar 3, 2012 6:53 AM
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On Friday, March 2, 2012 6:49:55 AM UTC-6, McHale, Paul wrote:
> So, here are some problems we face, but don't have great answers for in Mathematica.
>
> 1. Dimensional analysis. To do this, we must have unit support. The best description of this is the ability to calculate (V/R)^2 R and have it return a unit of watts. Other programs handily support this (though they are sorely lacking in other places :))

Probably not exactly what you want, but you might have a look here.

http://library.wolfram.com/infocenter/Conferences/7513/

In[40]:= minimalUnits[(v/o)^2*o]
Out[40]= {Watts}

> 2. Tolerances support. One difficulty we have is determining the min/max at a certain point in a circuit even if the circuit is not complicated to model. I use lists {Rmax,Rmin} and Table. Works, but is a little clumsy.
> [...]

Have you tried using Interval[...] to specify value ranges? For basic arithmetic this should offer some possibilities. If you are computing, say, solutions to differential equations with toleranced input values, that will be more of a challenge. In effect what one wants is some sensitivity analysis. Can be done (using NDSolve), but is not so simple. That is to say, I do not recall the details of the setup.

Daniel Lichtblau
Wolfram Research

Date Subject Author
3/2/12 McHale, Paul
3/3/12 Daniel Lichtblau
3/3/12 mike.honeychurch@gmail.com
3/5/12 McHale, Paul
3/7/12 Daniel Lichtblau
3/6/12 Dana DeLouis
3/7/12 Daniel Lichtblau
3/8/12 roby.nowak@gmail.com
3/9/12 David Bailey
3/12/12 McHale, Paul
3/13/12 Dana DeLouis
3/13/12 Bill Rowe
3/14/12 Yves Klett

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