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Topic: Non Linear Regression.
Replies: 5   Last Post: Sep 25, 2013 8:14 PM

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Alan Weiss

Posts: 1,325
Registered: 11/27/08
Re: Non Linear Regression.
Posted: Sep 25, 2013 3:27 PM
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On 9/25/2013 1:31 PM, dpb wrote:
> On 9/25/2013 10:03 AM, satyaraj wrote:
>> Hi everyone. Sorry i am very new to matlab and to nonlinear regression.
>> This is what i would like to do, i have the formula as stated below.
>> E=Summation of n (i=1) * [ yi- F(8,xi)] ^2
>> E = objective function F = reservoir model function 8 = unknown
>> reservoir parameters 2; = dependent variable (time) y; = independent
>> variable (pressure) n = number of data
>> The parameters 8, could be from 1 to 5 of them. Which each parameter has
>> their own formula linking one another.
>> such as tD = (0.000264kt) /
>> (porosity*viscosity*compressibility*radius^2)
>> *note : only k and t is not available. other values are.
>> So, when i supply huge amount of data for the time and pressure, t p, i
>> would like to calculate the parameters via iterations. would that be
>> possible?

> Sure....how best depends significantly on which toolboxes you have.
> If you have the Statistics Toolbox
> doc nlinfit
> doc nlintool
> doc nonlinearmodel
> If not, you can use the other minimization tools and write the
> objective function as above and solve with a little more detail needed
> to be included explicitly.
> --

In addition, if you have Optimization Toolbox there are the lsqnonlin
and lsqcurvefit functions.

Alan Weiss
MATLAB mathematical toolbox documentation

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