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

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0
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48 views

Need to utilize FindFit with specified x variable values [on hold]

I have a function that I need to fit multiple (5) input values for, but I only have the function defined for 12 specific variable x values due to the need to ...
0
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0answers
16 views

Binomial Regression where n > 1

I am not well versed in Generalized Linear Models, but am trying to use this approach to model some discrete data. I have binomial data where the sample size for each observation is the same size, ...
0
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1answer
49 views

Regression with 3 variables

I'm trying to find a function starting from its values but I can't find anything related to functions with 2 variables and I don't know how to go on. So, given this sample data, I'd like to know how ...
0
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1answer
46 views

How to fit this data to be used in NIntegrate later?

I have a list of data points that resemble a chi-squared distribution (long tailed gaussian) that I am having trouble fitting or finding an equation with. The goal is to use the fitted equation in an ...
1
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1answer
47 views

FindFit::nrlnum: error with FindFit

I am trying to write a code to fit actual data of the orbit of a star with Mathematica 8. First I tried to write a code to fit a mock orbit, using the Application with differential equations (the ...
0
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0answers
46 views

NonLinearModelFit - fit parameters in form of a list [closed]

I want to fit a sum of multiple normal distributions with an exponential background to multiple data sets. My model is: ...
2
votes
1answer
50 views

Test Goodness of fit for FindFit

Is there any way to get an estimate of the goodness of fit from FindFit, for instance getting the final error? The documentation doesn't provide any hints, and a quick Google search didn't return any ...
2
votes
2answers
63 views

FindFit working with Integrate but not NIntegrate - I am using “?NumericQ”

I'm having some syntax problems with finding a fit to an equation that doesn't have an analytical expression for it's integral. Because I think the problem is one of syntax, I am substituting a ...
2
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0answers
36 views

Is there a way to produce a FittedModel object as the solution to a regularized regression?

I can get the Ridge or Tikhonov regression solution to Y = \[Beta].X easily enough as ...
0
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1answer
23 views

Creating a matrix of specific points using a FittedModel [closed]

I used a NonLinearModelFit to generate a fitting object called nlm. How can I create a matrix of specific values of the fitted results (nlm) evaluated at input values contained within a separate ...
6
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0answers
96 views

Implementation of Partial Least Squares (PLS)?

I'm looking for a PLS implementation for Wolfram Mathematica. I just cant seem to find any implementation for it - do you know one? In general, I'm a bit confused that there exist only so few ...
1
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0answers
60 views

Fitting curves with NonLinearModelFit not working with charge and discharge like data

I'm trying to get a reasonable fit out of mathematica, but i'm not very practical with it. I'm not that good with mathematica at all actually(like cleaniness of the code...). btw, here's my problem: ...
0
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0answers
36 views

Troubles with FindFit for ODE (elaboration)

I have asked a question Troubles with FindFit for ODE and get a good-working answer from @belisarius. Nevertheless I need to clarify is it possible to define the same model with ...
2
votes
1answer
43 views

FindDistributionParameters and Hypothesis Testing

Please excuse me if I am making any logical error in posting this question since I am not a math major. However, let me post my question. I am trying to fit multivariate parametric distribution to ...
2
votes
1answer
92 views

How do I find out what a Mathematica function is doing (which numerical method it uses and how)?

Long story short, I am working on a project which entails fixing a bug I have found in Mathematica (8 and 10). In general, I would like to know what a specific Mathematica function is actually doing ...
-1
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0answers
17 views

how can I get the differece between a residual difference between a plot point and a 3d plane [duplicate]

I wish to both dynamically sum them up and also draw them rising or falling verically to the plane in the graph, is there a function to do this?
-1
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0answers
79 views

Im trying to get the total residual value from a plane of best fit

So I got the least squares plane in this question: How do I display the plane of best fit in 3D? However I need to wiggle the plain between its maximum error and its minimum on two of its three ...
1
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1answer
90 views

How to obtain the best possibe NonlinearFit

Here is some sample data ...
4
votes
1answer
73 views

Find GeometricTransform from 3D object external surfaces to a positional point cloud data

I am looking for another way to approach this problem. Any suggestion on how to optimize the computing speed is welcome. I have a BSplineFunction which accurately ...
1
vote
1answer
42 views

Mixture coefficients and Parameter estimation for moving Normal distributions

I am searching for a way to do the following steps below. I am stumped and I have stumped a few profs too. Any help would be appreciated. I would like to import data from, say, excel or a .txt file ...
0
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2answers
62 views

Handling msg for fitting

I have a trivial question: I do Monte Carlo with some curve fitting. Now always when a random run creates a complex fitting solution it should write 1 in a Matrix. How can I handle such msgs in a ...
0
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1answer
33 views

Fit inside a module [closed]

I have here a MMA NB which works fine outside the MODULE. BUt in the module routine there comes up an warning that the solution is not real. Can anyone here help please? ...
4
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1answer
91 views

Mystifying failure of NonlinearModelFit

Fitting the following two time-series (two repeats of the same exponential growth process) ...
0
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0answers
47 views

NonlinearModelFit indeterminate or not a list of real numbers

I'm trying to fit my data using NonlinearModelFit but keep getting errors that I don't quite understand how to correct ...
3
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1answer
95 views

Troubles with FindFit for ODE

I need to use FindFit for ODE with arbitary number of parameters. This code (from documentation) works: ...
0
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1answer
73 views

Fitting data with inclusion of constraints

How do I find a fit for the dataS (see below) with the constraint that the parameter np is an integer, and that the parameters la+lc = 100. A weak attempt at this is provided below for a specific ...
9
votes
1answer
460 views

Curve fitting by running through hundreds of models and return the one with best fit

In the past, I used to solve a lot of my regression analysis (curve fitting) problems with a program called DataFit which runs on Windows. It has hundreds of regression models which it runs through in ...
0
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1answer
86 views

Fitting data to a circle with FindFit

I'm currently trying to use the Mathematica's FindFit command to fit a curve of some data to the bottom half of a circle. The data is of the form ...
5
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1answer
163 views

Forcing NonLinearModelFit through a point

Like the title says, is there a way to make an NLM fit pass through a specific point.
0
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0answers
37 views

Using List/Histogram Data As A Weighted Function?

I have a list of data points that I would like to use as a weighted fucntion. The data represents the number of particles within a bin of a particle distribution. Ultimately I would like to multiply ...
0
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0answers
83 views

Non linear curve fit

I am trying to fit a non linear curve to my data which looks like following The code I am using is following. You can see I have six unknown variables ...
2
votes
1answer
52 views

Is there a way to show some “weighted” residuals after LinearModelFit?

I am fitting some functions to some data and then I want to analyze the residuals of that fit. I'd like to see how those residuals compare to the values of the original data, hence my "weighted" in ...
0
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2answers
62 views
0
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0answers
52 views

Can not understand the code to join points into line segments

I'm reading the CDF file from Making Formulas… for Everything in wolframalpha blog. It's hard for me to understand the In[17] code of function pointListToLines. I especially want to know what the use ...
2
votes
1answer
59 views

BSpline or other curve through arbitrary ordered sequence of two-dimensional points

How does one create a BSplineCurve or other smooth curve passing through each point in an ordered list, where the curve may be non-simple, i.e., can double-back upon itself, loop, and so forth as for ...
3
votes
2answers
140 views

Best fit equation from a scanned image

I am trying to extract a curve from a scanned graph and find a best fit equation. For example, starting from: How could one find an equation starting from the image file ?
1
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0answers
31 views

Error associated with parameters in Minimize (or NMinimize) in discrete fitting

my problem goes as follows: I need to a discrete fit of a discrete function. Say I have the following made up data points, which are generated by the parabola ...
0
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0answers
82 views

Multi-peak fitting

Suppose we have a data set that looks like this: I have to fit this data to 9 peaks knowing μ and σ beforehand & have to ...
1
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0answers
59 views

Updating procedural fitting algorithm to more efficient style?

For some time now, I have used this procedural programming approach to fit data in my research that is too cumbersome for the built in Mathematica functions. (Although this simple example works fine ...
0
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1answer
66 views

Equation of line from loglog plot

Given some data that looks linear on a ListLogLogPlot, how can I find the correct equation (and particularly, the correct slope of the line)? I have a sample code here ...
0
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0answers
37 views

How to perform a distribution fit test to censored data

With following code I will get an error: ...
0
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0answers
79 views

Curve fitting of a list

I have list obtained using an integrals. I want to obtain an analytical formula that fits my list using curve fitting. Please suggest a simple analytical structure that fits my curve. ...
4
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2answers
92 views

Remove redundant parameters from equation

I have random expressions like (b1 x + b2 x)/(b3 + b4/b5 x) + Sin[b6 x] where $x$ is a variable and {b1, ..., b6} are parameters to be fitted. This expression is ...
0
votes
1answer
73 views

Non linear model fit

I need to fit this, but for some reason I cannot... data = {{0.617,0.8}, {0.605,0.6}, {0.5997,0.4}, {0.5972,0.2}, {0.5985,0.1}}; soln = NonlinearModelFit[data, {y - 2478.82*wlog[kc + 1]}, {y,w,k}, ...
0
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0answers
54 views

Using FindFit to return a list of possible best fits

Can I use some variant of FindFit that will return a list of the best fit and some worse fits, not just the best fit? This is for a function where the residual function can have several local ...
5
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0answers
110 views

PenaltyFunction Option in NMinimize

I am curious if anybody has some experience in using the built-in Option "PenaltyFunction" in any of the numerical optimization functions like NMinimize. According to the documentation the user ...
1
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0answers
52 views

Findfit doesn't provide reasonable results when fitting a complex function [closed]

I am trying to fit some data using the function which contains two parameters (a, b) as described below. Hope to determine the a, b that best fit the data. My input is: ...
3
votes
0answers
55 views

How to derive SinglePredictionBands from a NonlinearModelFit model

I have found NonlinearModelFit to be extremely useful in my work. Here I have fit 4 points to a function and am being asked to explain how the 95% SinglePredictionBands associated with the plot below ...
1
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0answers
66 views

Simultaneous fitting to multiple data sets with multiple variables and some common parameters

I am trying to fit two data sets to a function model described below which share a few common parameters. Say I have two functions with some common parameter(s) ...