# Questions tagged [fitting]

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

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### Fourier series using DFT

I am trying a simple example to do a discrete Fourier transform. My goal is to use DFT to find the frequencies that have built the time signal and then to a good approximation, use DFT data to find ...
88 views

### How to plot this data set, ignoring the initial oscillation?

Suppose I have an array given as: ...
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### All composite numbers are crossed by the lines

I'm trying a version of the code with the concavity of the parabola upwards (y=x^2), but I'm not succeeding. I appreciate any help. ...
1 vote
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### How to exclude singularities for NMinimize

I have an messy expression and want to apply NMinimize to it, have no idea how to force NMinimize to ignore the singularities it ...
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### Fitting with Step Function (Beginner question) [duplicate]

I have data as below. ...
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### NonlinearModelFit extremely slow performance with a single iteration

I have been experiencing very slow performance of NonlinearModelFit. The code that in my case causes that is below. The first part gets the data, the model and ...
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1 vote
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### Using NonlinearModelFit output in multiple Plot instances within DynamicModule

I'm creating a script for interactive model fitting where the user selects a 'window' of the data to exclude from the fitting. I can come up with a MWE like the following: ...
212 views

### P-Values For LinearModelFit Changing Due To Ordering Of Features

The arbitrary ordering in a linear model of the independent variables should not impact the p-values for the coefficients of said model. However that is exactly what is happening here ...
409 views

### Finding an ellipse of minimum area that encloses a set of points

Is there a built-in function or set of functions in Mathematica that can take a set of points in the x-y plane and determine the ellipse of minimum area that contains all of the points? I am sure ...
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### Fitting problem for sigmoid like experimental data

I have data like this ...
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### Curve fitting with Mathematica

I am trying to find de parametric equations of this curve (the curve in that sector of circle): What I've tried: ...
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### FindFit or NonlinearModelfit for sinusoidal function

I am trying to fit this data set into a specific sinusoidal equation. The equation is shown like this. ...
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### Dealing with derivative of noisy experimental data

I have the following (time, position) dataset ...
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1 vote
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### The best way to guess the needed data using Mathematica?

I have a question, which is not entirely related to Mathematica, and would appreciate any help on this matter. I have the following dataset, which shows the growth of a bacterium in a specific medium: ...
316 views

### Why does this simple fit run forever?

The following fit runs forever on my laptop; how to speed up? ...
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### Solve constraints don't work properly

So in my previous question, I was trying to find two parameters kV and km for an implicit function using FindFit(FF) command and I did it but the problem is that it takes around an hour to do it. ...
1 vote
55 views

### My sinusoidal fit requires an unused extra constant to work

I am trying to fit a sinusoidal curve onto the following data: ...
126 views

### Problem related to fitting a damped sine function

When I try to fit an exponential damped sine, it acts as if it cannot reach the amplitude at all. What do I change? link to data: datafile Getting data: ...
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1 vote
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### How do I fit unknown function to my data?

I have a set of data, to which I am trying to fit an unknown function. I believe it might be a logarithmic function, but I am not sure. Can you help me find a working model? ...
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### How can I approximate a function with composite polynomials?

I know that to approximate a function with for example $f(x) = \sin(x)$ using polynomials with degrees up to 4, I can use the Fit function : ...
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1 vote
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### How to include Manipulate in fitting?

I'm trying to fit three differential equations to two data sets, using the code developed by @Cesareo, as follows: ...
231 views

### How can I use option Weights for fitting?

I have the following dataset (time vs. a quantity called $s$): OPD = {{0, 0.0305}, {3, 0.14}, {6, 0.5}, {17, 4.02}, {19, 5.04}, {21, 5.52}, {24, 5.76}}; To the ...
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### Chi-square minimization error

I'm trying to fit some data into a model using the standard procedure of minimizing the chi-square function using this code: ...
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