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

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0
votes
1answer
59 views

How to force a Range on Fit?

I have 1001 points between {x,-5, 5}. I wanted to fit a polynomial over the data but when i try: Fit[Flatten[data], {0, x, x^2, x^4, x^5, x^6}, x] ... the range ...
3
votes
1answer
61 views

Looking for a convenient way to replace a large data sample with an analytic approximation

Suppose that data is a large data sample, and that Histogram[data] produces a very smooth-looking distribution. Since ...
3
votes
2answers
263 views

Mathematica Interpolation or approximation

I have lists of points X and Y. {1212,1216,1217,1219...}, {1,2,3,4,5,6...} I combine ...
6
votes
2answers
204 views

How to measure accuracy of prediction distribution?

I have been trying to come op with a way to test if my dataset follows a Poisson distribution. Normally one would use the DistributionFitTest function, but here is ...
1
vote
1answer
71 views

NonlinearModelFit memory problem

I have a problem while trying to make a nonlinear fit of the following data: qn = NSolve[Tan[q] == 3*q/(3 + 1870715*q^2) && 0 < q <= 65, q] ...
2
votes
1answer
133 views

How can I fit cyclic experimental curve with a couple of differential equations?

I have an experimental cyclic curve which looks like this: ...
1
vote
2answers
66 views

Nonlinear fitting of a Gaussian beam model

I am having some troubles with the NonlinearModelFit function. However hard I try, I cannot get a nice fit curve for the data points. I know the parameter "a" is about 15*10^-6 but even if I plug in ...
3
votes
0answers
53 views

PearsonChiSquareTest for count/frequency data?

I read with interest a previous question on the PearsonChiSquareTest from a few years ago, and one answer was very helpful: Performing a chi-square goodness of fit ...
14
votes
2answers
651 views

Fit a function to data so that fit is always equal or less than the data

I have a set of measurement data and I try to fit there a function (a Exp[b x] + c Exp[d x] - o). I have two problems: The fit function does not converge nor ...
0
votes
0answers
37 views

Is it possible to get the error estimates of predicted values computed by FindMinimum using the Levenberg Marquardt method?

I use the LevenbergMarquardt method of the FindMinimum function to minimize a residual function (mathematical-optimization). This residual function is computed from experimental data and the solution ...
2
votes
0answers
107 views

How to fit two datasets with common fit parameters?

I have two data sets which go: ...
0
votes
1answer
43 views

Independent test of residuals, absolute member equal zero

Does Mathematica offer any test for confirm independence of residuals? except DurbinWatsonD. And I would like to ask how to make some test in regress function which tests absolute member equal zero. I ...
0
votes
0answers
51 views

How to fit a plot with error bar as weight?

I try to fit a line which can fit through the points considering the error weight of each coordinate. Is it possible to do in Mathematica? I can only find Fit function which did not do what I really ...
14
votes
2answers
283 views

Fitting Stradivari's scroll

How can I find the simplest curve that gives me a scroll like this? This is where I am at the moment and doing it by hand is becoming more and more cumbersome. First, take a drawing of the scroll ...
4
votes
1answer
92 views

Finding NonlinearModelFit of multiple data sets with the same parameters and in two dimensions

I have multiple sets of data (between 3 and 6 depending on the cases) dependent of space, time, and some parameters. The data are the response of a harmonic oscillator under a non-trigonometrical ...
1
vote
0answers
72 views

NonlinearModelFit with constraints error estimate integrity [closed]

I use NonlinearModelFit with additional constraints on the fitting parameteres. When I use "ParameterErrors" or ...
3
votes
3answers
107 views

Fitting problem

I have two points stored in data: data = {{0.0166667, 2.86927*10^-12}, {0.0333333, 1.12725*10^-11}}; ...
0
votes
0answers
48 views

Fitting 6 differential equations to 6 sets of data

I am using the newest Mathematica and I am trying to fit a set of 6 linear differential equations to a set of experimental data for each of the six variables. I am a baby beginner at this and could ...
5
votes
1answer
214 views

Modeling of soccer results using GeneralizedLinearModelFit

I am trying to recreate the regression in "Analysis of sports data by using bivariate Poisson models," which can be found here, http://tolstoy.newcastle.edu.au/R/e8/help/att-6544/karlisntzuofras03.pdf....
0
votes
2answers
105 views

Find min-max for slope in linear fit

I have a following data which follows a linear model with intercept zero, i.e. $$y = mx $$ ...
1
vote
2answers
90 views

List argument for NonlinearModelFit

If I have a function of list argument (presumably with large number of entries), how can I pass it to NonlinearModelFit? I don't want to pass it by pattern checking ...
0
votes
0answers
69 views

Exact meaning of `VarianceEstimatorFunction`

After reading the documentation, it's still unclear for me what VarianceEstimatorFunction does when fed with two arguments: ...
1
vote
0answers
35 views

Fitting Data when both Variables Have Uncertainties [duplicate]

Does there exist a method in Mathematica for fitting some function f(x; a, b)=y (with parameters a, b) to data of the form {x, y} when both x and y have different uncertainties? It seems like it would ...
0
votes
2answers
121 views

A case of complicated fitting of multiple datasets

I've stumbled upon a difficulty while trying to do some fitting which may be called sorta complicated. I'll try to introduce my problem step by step. To begin with, I have a number of datasets ...
1
vote
1answer
93 views

Sum to Zero Constraint in GeneralizedLinearModelFit

Is there a way to impose a constraint on a generalized linear model fit in Mathematica? In R, when using the glm() function, you can set options(contrasts=c('YY.sum', 'ZZ.sum')). Is there something ...
0
votes
1answer
99 views

How to Find minimum and maximum using `FindMaximum[]` and `FindMinimum[]`

this is the data that i use to plot. data_damped_osccilation this is my code so far, however it still give me error ...
0
votes
2answers
63 views

NonLinearModelFitting constant offset problem

I have written the following code: ...
2
votes
1answer
133 views

Standard error of linear fit parameters

I fitted data belonging to a MSD (mean squared displacement of a vibrating micrometer sized particle) by using a linear function: ...
0
votes
1answer
49 views

Failed to extract parameters by fitting data with ODE

I'm trying to extract 4 parameters by fitting one set of data with an ODE via NonlinearModelFit. I originally thought the process should be straightforward, but later on I found I was totally wrong. ...
3
votes
2answers
225 views

Is there is a decreasing function that fits my data?

Cross-posted in http://tieba.baidu.com/p/4440556337 http://tieba.baidu.com/p/4440547130 I was wondering if there is a function that fits the following data perfectly or properly. There is a ...
0
votes
1answer
39 views

NonlinearModelFit for analytical data is giving errors [closed]

"x is lambda, y is alpha, z is the factor of pressure" ...
0
votes
0answers
46 views

fit multiple dataset with a single ODE to extract parameters

I found my problem very similar to the one discussed in here. But I'm having difficulties to fit multiple dataset (with varied temperatures) to a single ODE. The hurdle for me now is since the rate ...
3
votes
2answers
256 views

Why can't FindFit get the proper result in this problem?

Cross-posted in http://tieba.baidu.com/p/4425634583 The mathematica helps me solve one differential equation in numerial method and got the data of the answer,but the taylor series fit is not good in ...
0
votes
0answers
83 views

Maximum Likelihood Estimation of Gamma-distribution Scale parameter

I have the following tasks: Generate random sample with given parameters shape = 2, scale = 0.001 and shape = 2, scale = 1/1200 for the right censored sample; Using Maximum Likelihood Method ...
0
votes
1answer
64 views

FindFit only fitting portions of data

I'm currently trying to fit some complicated data sets and I am having some luck. The higher temperature data works just fine with FindFit. Unfortunately, however,...
0
votes
0answers
44 views

Plotting error bars in both dimensions for straight line model [duplicate]

I want to fit a straight line model of the form $y_i = a+ b\ x_i$ to the list of $(x, y)$ pairs given below. How can I plot the data with error bars in both coordinates? ...
2
votes
1answer
88 views

Fitting EV charging curve

I would like to fit my set of data (x = time and y = power) as seen below, and obtain function of x describing it as close as possible, in order to manipulate it (applying different SOC, time offsets ...
0
votes
2answers
62 views

Plotting plane from a matrix or data table

After weeks collecting data I've decided to pass my results through Wolfram Alpha and see what it gets. The results are amazingly useful, specially the plane generated by linear regression. It is ...
13
votes
5answers
2k views

Fit image of mountain to gaussian

I want to detect the edges of an image of a mountain and then fit that to a gaussian. I am unsure about how to only get the mountain edge, rather than every single edge in the image. How do I ...
1
vote
2answers
72 views

Putting suitable constraints on the `Find` family of functions

Can any of the Find group of functions be used to get a good curve-fit for a range of data, if the value of $f(1)$ is known, and the value of $\lim_{n\rightarrow \...
2
votes
0answers
61 views

Algorithm used by Fit[]

Does anyone know what algorithm Mathematica's basic Fit[] function uses? Is it proprietary? I'm trying to do some pretty basic, linear, polynomial data fitting (...
-2
votes
1answer
102 views

Computing least squares error [closed]

I have a mathematica subroutine setup that computes the least squares approximation as follows ...
4
votes
4answers
201 views

Fitting Coxian distribution to some data

I'm trying to fit a transformed (actually shifted to the right) Coxian distribution to some data ( if needed an example set is here Sim data ). I've tried a number of ways for this: ...
5
votes
0answers
114 views

Ridge and lasso regression missing? [closed]

There is no implemented command to perform ridge or lasso regression? I couldn't find it in the documentation. Might be there are add-on packages I am not aware of.
3
votes
0answers
98 views

Writing a function to set up and solve the least squares problem

I have setup the explicit line equation for a given set of points using least-squares approximation and the knots computed below. I have tried extending the same code for use with an arbitrary degree, ...
1
vote
2answers
148 views

Problem fitting a exponential function to data points [closed]

finale edit: i found someone who solved my problem via matlab. therefore i wont try out the proposed solutions now, but wont delete my question in case someone might have use for the proposed ...
1
vote
0answers
49 views

NonLinearModelFit to a Function [closed]

I have a multiple dimension function that is fairly complicated. Instead of simply using Series to get a taylor series of the function, I would rather specify my ...
3
votes
2answers
183 views

Low quality of estimated parameters with NonlinearModelFit

I'm trying to fit formula: ...
5
votes
1answer
112 views

Why is NonlinearModelFit not working?

I have a set of x,y-values ...
1
vote
1answer
82 views

Faster way to test possible points-to-plane-fitting identity?

Summary: I want to confirm the three sum-defined quantities in https://github.com/barrycarter/bcapps/blob/master/STACK/planetest.m (also below) are identically zero for all values of n>=3. While ...