Questions on the use of Mathematica to construct models for approximating empirical data.

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18
votes
3answers
1k views

Data fitting with Image processing feature detection

I have some 2D data that once plotted looks like the following ...
4
votes
5answers
1k views

How to plot Fit functions?

If I do something like this f[x_]:=x^2 Plot[f[x],{x,1,10}] Mathematica plots the function $f(x)=x^2$, as expected. However, ...
0
votes
3answers
340 views

Creating simple procedure for The Least-Square $m^\text{th}$ Degree Polynomials

I am CS major, taking Computational Numerical Analysis course. Instructor gave us freedom of choice, we were allowed to use anything or any computer language we picked, I picked Mathematica.This is my ...
2
votes
0answers
188 views

How to predict some constant number of values with NeuralNetworks

Example: << NeuralNetworks` data = {Sin[#]} & /@ Range[0, 4 Pi, 0.5]; learn = data[[1 ;; 15]]; Now, lets fit our neural network: ...
3
votes
1answer
444 views

Why FindFit could not exactly fulfill condition?

I tried to fit some data with boundary conditions, but FindFit just could not work. Does anyone know the reason? Details: The function to be fitted is ...
18
votes
2answers
1k views

Finding the area, algebraic curve and jaggedness of an arbitrary shape

I start with a photograph of a shape (physically made by the flow of a liquid into another), of which I can extract the border, manually or using Mathematica's feature detect feature : Using the ...
29
votes
4answers
4k views

Simultaneously fitting multiple datasets

What is the proposed approach if one wants to simultaneously fit multiple functions to multiple datasets with shared parameters? As an example consider the following case: We have to measurements of ...
4
votes
3answers
524 views

Output of NonlinearModelFit differs from the correct result

I'm having a bad time dealing with the NonlinearModelFit in Mathematica 8, since the result given is a bit imprecise. An example is given on potential regression, ...
10
votes
2answers
298 views

Unexpected differences with various uses of NormFunction

I would expect all of the following to give the same answer (2.12467) but only half of them give this answer. The others seem to be using the default ...
2
votes
2answers
247 views

Non-linear trend reduction with missing data

How can I reduce a non-linear trend of some data series if there are parts of "no data", represented by the value 99999? For example: ...
5
votes
2answers
289 views

How to find Matano plane

I have discrete collection of data points (10 to 10^4). I want to describe them by a continuous function and find a x value z, ...
15
votes
2answers
964 views

FindFit returns Infinity::indet error when data contains {0,0}

Let's consider the following data: data = Table[{q, 2*q^2}, {q, 0, 2}]; and then, do a very simple fitting to this data: ...
5
votes
0answers
572 views

Analytical model fitting

I have a special type of model fitting problem that I am trying to solve in Mathematica. Any insight how to attack it using available tools of Mathematica will be great to hear. We have a variable $$ ...