Questions tagged [fitting]
Questions on the use of Mathematica to construct models for approximating empirical data.
-2
votes
0answers
23 views
Why can't a make a new varible for a graph fit? [on hold]
I'm trying to make a Least Squares fitting in Mathematica, but it says it can't interpret my data to do a fitting. It lets me plot the data, but that's it. Is there something wrong with my data? I ...
0
votes
1answer
13 views
Fit data with a given function depending on parameters
I want to fit the data of a star's temperature with a function from a model. That function depend on several parameters. I want to know how can I find the value of those parameters.
The data is:
<...
-3
votes
1answer
104 views
Fit this data to a model in mathematica
I need to find a distribution or a model to fit this data set in Mathematica
...
0
votes
2answers
75 views
Obtaining the polynomial describing the motion
I have the following data points:
Clear["Global`*"]
dados={{0,0},{1,1000},{2,-750},{3,250},{4,-1000},{5,0}};
From these data I obtained the following ...
0
votes
3answers
88 views
How to get a plot with more precision in the data points?
Working with other software called SolidWorks I was able to get a plot with a curve very close to my data points:
I tried to get a plot as accurate as this, but using the ...
1
vote
2answers
29 views
How to draw lines connecting nearby points [duplicate]
Suppose I have the following example data,
data = Table[{Cos[theta], Sin[theta]}, {theta, 0, 2 Pi, Pi/8}];
which, when plotted, looks like this,
...
0
votes
2answers
78 views
Listplot, Plot and e function bug
For a project I have, I have let a program calculate required interias and friction for my system are R and J in the params. That program calculated 0.5*10^-3 and 0.013~ respectively. I'm trying now ...
0
votes
0answers
18 views
Fitting Categorical/Nominal Variable in NonLinearModelFit
I have a dataset with 4 continuous variable and 3 categorical variables. S far I have found a model which has all continuous variable using
...
2
votes
2answers
61 views
NonlinearModelFit doesn't seem to work with inverse function - please help!
I have the following defined:
lvf1 = Table[{i, 1/(10 - i)}, {i, -100, 100}];
If I just run this, it gives me a "Power: Infinite expression 1/0 encountered." ...
2
votes
1answer
72 views
Linear mapping to fit points to subset of other points
I have some set of points making a specific pattern. I want to find a linear mapping (dilations + translations) to find a similar pattern in a second larger set of points. I want to find the best (or ...
0
votes
1answer
44 views
Forcing a 2D nonlinear fit through a set of points
I am trying to fit a set of data points using exponential functions as the underlying process suggests an exponential decay. The data points are:
...
6
votes
2answers
422 views
Fitting PDF to two normal distributions
I'm trying to fit this data
As you can see there's two peaks. I want to fit this curve with two normal distribution with the same variance but different mean.
So far I've got this:
...
1
vote
1answer
85 views
How do I access individual groups after using GroupBy on a Dataset object?
I want to read in an xlsx (Excel) or TSV (tab-delimited) file, assuming this
results in a rectangular table of data. Then I after applying GroupBy (using
multiple keys), I should have several ...
0
votes
1answer
48 views
Find interpolation with derivatives at some points
I am trying to find out how to find a good interpolation of a periodic function I have from some data points.
The only problem is that I need to make sure that derivatives at the starting and ending ...
4
votes
2answers
241 views
Problem in using FindFit
I have the following set of data
data={{0,0,0},{0,2,1},{0,4,2.247},{0,6,3.627},{0,8,5.031},{1,0,3.346}};
where the values are {n, L,$\varepsilon$} and satisfy ...
0
votes
1answer
27 views
1
vote
1answer
46 views
How to pass starting values in matrix form?
Consider the following MWE, where I try to pass starting values to FindDistributionParameters[]:
...
14
votes
1answer
144 views
What are the practical differences between Fit, NonlinearModelFit, and FindFit
What are the practical differences between:
FindFit,NonlinearModelFit,and Fit. Do they call ...
1
vote
2answers
65 views
Evaluating a formula that uses summations and products of vectors
Could someone tell me how to find beta1?
I have the following data:
I don't know how to write beta1, and I don't find ...
0
votes
2answers
44 views
Difficulty fitting an equation to a data set using exponential growth and logistical growth [closed]
I'm having an extremely hard time getting linearmodelFit, findFit, or nonlinearModelFit to give me an output that I can work with and I can't seem to find the problem.
My list is
...
0
votes
2answers
45 views
Partitioning Mixture Distribution Dataset into constituent Distributions
Suppose I have a dataset that is derived from a random sampling from a mixture distribution
...
1
vote
1answer
66 views
Estimation of the error for zero degree of freedom fit with error bar
I am performing a fit on experimental data with zero degree of freedom but with error bar using NonlinearModelFit:
...
0
votes
1answer
80 views
0
votes
0answers
41 views
Simultaneous fitting of polynomial parameters to data [duplicate]
I have two following data-sets:
...
0
votes
1answer
56 views
Fitting complex equation
I used the following code for fitting but it does not produce an output.I kept it nearly 3 to 4 hours but it does not give any output. How should I make it correct?I have used two equation(f1,f2).I ...
0
votes
1answer
97 views
How to do good surface fitting in Mathematica?
I would like to fit a 3D surface in Mathematica, and I can do a rough fitting using the following code:
...
0
votes
0answers
48 views
1
vote
1answer
30 views
Get properties of a list of fitted models (objects)
If I do a fit, such as
nlm = NonlinearModelFit[data, {x^a Cos[b x + c]}, {a,b,c} ,{x}]
then you return a FittedModel object, ...
1
vote
1answer
49 views
0
votes
1answer
104 views
Problem using Nonlinearfit on integral function
I tried to fit my data with a very complicate Integrated function. But I get many errors messages when I perform the fit. For exemple I get :
NIntegrate::inumr: The integrand ....has evaluated to ...
0
votes
1answer
46 views
Model fitting for concave curve: test if asymptote or convergence exist
I am asking a double check if conceptually I set up proper model and proceeding in good direction to drive conclusions.
I have a distribution that looks like this:
I want to test if for increasing x ...
1
vote
1answer
73 views
Fit Gaussian Function [duplicate]
I want to fit the Gaussian Function for the following data. How should I do it?
...
10
votes
1answer
138 views
Quantile Regression using Neural Networks (Custom Loss function)
I would like to perform a Quantile Regression within Mathematica's neural network framework.
Since there exist a couple of tutorials for this exact problem in Tensorflow, i.e. Deep Quantile ...
0
votes
1answer
38 views
4
votes
2answers
73 views
Why does the PearsonChiSquare from FindDistribution and DistributionFitTest differ by a factor of $10^{20}$?
This is similar to the unanswered "Why the results of FindDistribution and DistributionFitTest are not consistent?" My more specific question is: Why do the PearsonChiSquare values for ...
0
votes
1answer
57 views
What is the best fit for this data?
First I entered the data and graph it, then I used the non-linear adjustment command to have a model of my data, I asked Mathematica for the square r, to know how good the model was, then I put ...
1
vote
1answer
60 views
Linear regression with weighted data?
LinearModelFit doesn't seem to support WeightedData objects. Is there anything I can do smarter than repeating the data ...
0
votes
2answers
70 views
4
votes
2answers
121 views
How do I treat the results of Fit as text?
I would like to take the results of Fit (or any FittedModel) and treat them as text, including making substitutions for the ...
2
votes
1answer
72 views
Fitting an equation to data set, am I doing this right?
I have a large data set of different values of time. I want to make
1) a histogram
2) fit an exponential function of form A+B*exp(-t/b) from the data
To my understanding, this is how I'd do it
<...
0
votes
1answer
54 views
Estimating parameters for pair of differential equations efficiently
I'm trying to estimate the parameters for the following pair of differential equations
...
0
votes
0answers
30 views
Ranging the parameter in Fitting
I want to apply a range for parameters(a,b,c,d).What is the correct way to do it?
...
0
votes
0answers
48 views
Parametric solution of a system of two nonlinear ODEs with data describing only one the functions
I have the following pair of nonlinear ordinary differential equations
...
3
votes
0answers
61 views
Deal with noise and missing points in data [closed]
I have run a simulation which has resulted in some bad data (see graph below). What would be the best way to detect and interpolate the missing points in Mathematica (i.e. remove the noise)?
Raw ...
1
vote
1answer
45 views
Why does LinearModelFit give me an equation in $z$ rather than $x$?
I am working on a Mathematica notebook and making graphs for my lab. I can't make a graph for my linearized data as LinearModelFit gives equation in ...
0
votes
1answer
99 views
Convolve and fitting
I want to convolve two equation, then I want to find the parameters. But it doesn't give the answer and Takes too much time. What is the wrong with my code?
...
1
vote
1answer
90 views
Difficulty with FindFit with complex equation
I want to fit the following equation for my experimental data. I used the following code but it does not give the answer.
...
0
votes
0answers
51 views
NonlinearModelFit Method-> “LevenbergMarquardt”, “Newton”, “QuasiNewton”, etc?
Could someone please point me to a tutorial comparing and contrasting the advantages and disadvantages of the many methods to choose from when applying NonlinearModelFit?
3
votes
2answers
75 views
How to correctly write a PDE solving module for NonlinearModelFit
I need to fit a model defined by numerical operations to test data and find the parameters of the PDE. The problem is that I have to NIntegrate the result obtained ...
0
votes
1answer
75 views
How to get more digits from Fit
Taking the example from the Mathematica documentation for Fit, consider the following
...
