Re: Non Linear fit problem
- To: mathgroup at smc.vnet.net
- Subject: [mg67827] Re: [mg67799] Non Linear fit problem
- From: Mary Beth Mulcahy <Mary.Mulcahy at colorado.edu>
- Date: Sun, 9 Jul 2006 04:50:58 -0400 (EDT)
- References: <200607080856.EAA20400@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
It sounds like you have measured t1 and t2 (since you say you plot two temperatures), then I assume you know the soil depth where you measure, and that k is a constant. So I am confused as to what unknown parameter you are fitting to. Do you want to fit the lag? If so, it is an easy thing to do on Mathematica. Is this your question? Mary Beth Quoting Raj <rajanikanth at gmail.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 > -- Department of Chemistry and Biochemistry University of Colorado Chemistry 76 Boulder, CO 80309-0215 (303) 492-0579
- References:
- Non Linear fit problem
- From: "Raj" <rajanikanth@gmail.com>
- Non Linear fit problem