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Re: Engineering requests
Posted:
Mar 3, 2012 6:53 AM


On Friday, March 2, 2012 6:49:55 AM UTC6, 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



