MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Non Linear fit problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg67799] Non Linear fit problem
  • From: "Raj" <rajanikanth at gmail.com>
  • Date: Sat, 8 Jul 2006 04:56:03 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

I have a problem of fitting two temperature lists to an error
function. The physical description of the problem is as follows:

t1 is a list of temperatures on the surface of the soil and t2 is the
list of temperatures at a certain depth (say x).
We know that the dependence of t2 on t1 is as

t2 = t1 Erfc[x/(2 sqrt(k)]

 where x is the depth at which t2 is measured and k is the constant of
diffusivity.

When I plot the two temperatures, I can see that t2(temperature at a
depth) lags behind t1 by a certain time.
 My problem is to find the temperature at any depth given the
temperature at the surface (t1). Is there a way in Mathematica to find
k such that t2 and t1 have a close fit?


Thanks,

Raj


  • Prev by Date: Re: Re: Speed challenge: Improve on integer frequencies from Count?
  • Next by Date: Re: Accuracy of Norm[{0``1}] is infinity?
  • Previous by thread: RE:Symbolic Calculus: How to reduce a function to two functions
  • Next by thread: Re: Non Linear fit problem