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MathGroup Archive 2006

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Re: Re: Differentiation problem/bug?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg69854] Re: [mg69783] Re: Differentiation problem/bug?
  • From: Arturas Acus <acus at itpa.lt>
  • Date: Tue, 26 Sep 2006 00:59:09 -0400 (EDT)
  • References: <eevrea$gfd$1@smc.vnet.net> <200609230844.EAA22439@smc.vnet.net>

Dear Paul,

> I never use NonConstants. Also, it is a good idea to avoid using 
> variables involving capital letters. For calculations where there is 
> implicit dependence with respect to a variable I use Dt instead. 
> 
>  inp = 1/4 + 3/8/E^(2 I f) + (3/8) E^(2 I f) - (1/4) E^(-2 I f - I t) + 
>  (1/4) E^(2 I f - I t) - (1/4) E^(I t - 2 I f) + (1/4) E^(2 I f + I t) +
>  (1/16) E^(-2 I f - 2 I t) + (1/16) E^(2 I f - 2 I t) + 
>  (1/16) E^(2 I t - 2 I f) + (1/16) E^(2 I f + 2 I t) - 
>  1/8/E^(2 I t) - (1/8) E^(2 I t)
> 
>  Dt[t, r] ^= 0;
> 
>  Dt[inp, r] // FullSimplify
> 
> Cheers,
> Paul
> 
> _______________________________________________________________________
> Paul Abbott                                      Phone:  61 8 6488 2734
> School of Physics, M013                            Fax: +61 8 6488 1014
> The University of Western Australia         (CRICOS Provider No 00126G)    
> AUSTRALIA   

Could Your share any thoughts why this way is more preferable.

For example, using Dt I should explicitly write down rules not only for
independent variables, but for model parameters also. Thus model
variables and parameters mixes up, which for my opinion doesn't look
nice from the point of view of logical consistence. Anyway I know You
never did it without some motivation. Share please.

Sincerely, Arturas Acus 





>                             http://physics.uwa.edu.au/~paul
-- 
Arturas Acus <acus at itpa.lt>


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