Questions on the use of Mathematica to construct models for approximating empirical data. (FindFit[], Fit[], LinearModelFit[], NonlinearModelFit[], etc.)
11
votes
4answers
2k views
Using FindFit to fit $a\,b^t$: how to avoid introducing complex numbers?
I'd like to find a model $f(t)=a\,b^t$ which matches the following data
...
14
votes
3answers
808 views
Mathematica envelope for the bottom of a plot, a generic function
I have the following set-up:
xaxis = Table[x, {x, 0, 10, 0.01}];
yaxis = Table [Sin[x] + Abs[RandomReal[{-1, 1}]], {x, 0, 10, 0.01}];
ListLinePlot[Transpose[{
xaxis, yaxis}]]
My ...
14
votes
5answers
2k views
Estimate error on slope of linear regression given data with associated uncertainty
Given a set of data, is it possible to create a linear regression which has a slope error that takes into account the uncertainty of the data?
This is for a high school class, and so the normal ...
24
votes
4answers
2k 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 ...
11
votes
4answers
3k views
Problem with NonlinearModelFit
I'm having trouble with a non-linear fit:
fit = NonlinearModelFit[data,
y0 + A Sin[\[Pi] (x - xc)/w], {y0, xc, A, w}, x]
where ...
10
votes
3answers
857 views
Fitting fractional complex data with NonlinearModelfit
I've difficulites with the NonlinearModelFit function.
In principle Mathematica should be able to deal with complex data.
E.g. if I define the following table
...
7
votes
6answers
2k views
How to determine the center and radius of a circle given three points in 3D?
I was wondering if anyone could give me a hand with this problem I have.
I have six points on a plane, and I am trying to determine if they form a circle or not.
I know that any three points in 2D ...
8
votes
3answers
461 views
Ηow to create an interpolated CDF from its samples?
I want to use a distribution I have only aggregate statistics on, namely its CDF sampled at certain points. I would like to keep it "nonparametric" (remain noncommittal on the parametric form), but I ...
16
votes
3answers
907 views
Data fitting with Image processing feature detection
I have some 2D data that once plotted looks like the following
...
10
votes
2answers
366 views
Is it possible to use the LevenbergMarquardt algorithm for fitting a black-box residual function?
I have a black-box multiargument multiparametric function of the type SRD[dataPoint_List,params_List] which accepts experimental data along with the parameters of ...
10
votes
3answers
760 views
How to use FindFit to fit an implicit function?
Now I am trying to fit some data with a implicit model function.
Firstly, I tried a toy example.
Toy example with input and output
...
30
votes
4answers
901 views
How to visualize 3D fit
I have a data set of x,y,z values and I fit a function of x,y to the data. This works, but I can't come up with a nice way to ...
12
votes
4answers
675 views
Mathematica Implementations of the Random Forest algorithm
Is anyone aware of Mathematica use/implementation of Random Forest algorithm?
13
votes
5answers
357 views
How to perform a multi-peak fitting?
I am wondering how to implement the multi-peak detecting and fitting in Mathematica. Following is an example of fitting the data using three peaks (such that the data ~ peak1 + peak2 + peak3).
The ...
4
votes
1answer
452 views
How do I find the best parameter to fit my data if the model is a interpolating function?
Hi I have a question regarding to find the best parameters for my model to fit my data.
I have 3 ordinary equation, and I now just picked some parameters (...
2
votes
1answer
288 views
Combined fitting via NonlinearModelFit
I am trying to fit my data to a combined function model. Say I have two functions with some common parameter(s)
f[x_]:= a*x^2 + b*x + c
g[x_]:= d*x^2 + e*x + c
...
5
votes
0answers
202 views
Mathematica vs Sigmaplot (Non LinearModelFit)
I asked a question in a previous post that was closed because "The title of the question is not correct and the issue here is too trivial to help anyone later".
NonLinearModelFit
It's possible ...
3
votes
5answers
463 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, ...
2
votes
1answer
68 views
making a function of fit results
I have 13*25 datasets consisting each of around 40 points.
They are all linear I can easily fit them using fit function but my problem is when I want to call them I want them to be functions. I want ...
2
votes
0answers
90 views
Is it possible to marginalize one or several parameters obtained from fitting procedure?
Statistical model analysis package has a few fitting functions. Their arguments are data points, fitting model and parameters in the fit. The result is a set of best values for parameters, which ...
