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Questions tagged [non-linear-regression]

In statistics, nonlinear regression is a form of regression analysis in which observations are modeled by a function which is a nonlinear combination of the model parameters and depends on one or more independent variables.

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nonlinear regression with exp(-exp(-x/c)) as model (R,nls)

I have a hard time fitting the following model to subsequent data: y = a * exp( - b * exp( -…
m2k1
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stat_smooth with complex function

I would like to use non-linear regression within ggplot, such that I may plot data and fit a curve to the reaction rate r = (k1*PA*PB^0.5)/(1+k2*PA^0.5) where PA and PB are tabulated against reaction rate r. I would like to find constants k1 and k2.…
deposition
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Finding appropriate formula for non-linear regression in R

I am trying to calculate a non-linear regression for my data in R. I am having trouble finding an appropriate formula and parameter values. My data looks like this: I have been using the nls and nlrq functions, which I believe to be suitable, but…
user964689
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Alglib Data fitting with minlmoptimize does not minimize the results. Full c# included

I'm having trouble implementing the lm optimizer in the alglib library. I'm not sure why the parameters are hardly changing at all while still receiving an exit code of 4. I have been unable to determine what i am doing wrong with the documentation…
Paul Nobrega
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How to smooth non-linear regression curve in R

So I'm asked to obtain an estimate theta of the variable Length in the MASS package. The code I used is shown below, as well as the resulting curve. Somehow, I don't end up with a smooth curve, but with a very "blocky" one, as well as some lines…
RBS
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How can I use S-curve(sigmoid) in mutivariate nonlinear regression in R?

I am working on Market Mix Modeling - I need to capture impact of different marketing variables on sales of a product through s-curve. Below is the equation I need to use - sales = 1/[1+exp((a1-TV)/a2)] * 1/[1+exp((b1-Radio)/b2)] *…
Sanjog Kumar
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using nlsLM() and < length of 'dimnames' not equal to array extent> error

The measurment points (y_i, t_i) are given (whereas in this minimal example the y_i is only 3-dim vector (originally from R^6) and t_i fixed time point. I had to (Not sure if the code, the way it is right now, expresses it) to apply the…
Jelena
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Improve Polynomial Curve Fitting using numpy/Scipy in Python Help Needed

I have two NumPy arrays time and no of get requests. I need to fit this data using a function so that i could make future predictions. These data were extracted from cassandra table which stores the details of a log file. So basically the time…
Abhinav Sinha
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Force specific interactions in Package 'earth' in R

I am using the 'earth' package to construct a Multivariate Adaptive Regression Spline model. Using the earth function, is there a way to allow interactions ONLY between certain predictor variables? For example, if I want to model y as a function of…
Angela
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Regression estimation in Eviews

I estimate the dependency of export,gdp and human capital. If choosing the linear method, I got this: Dependent Variable: EXPORTS Method: Least Squares Date: 05/23/15 Time: 18:20 Sample: 1960 2011 Included observations: 52 Variable …
July
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Non Linear Regression Error (Single Gradient Matrix)

I've seen a few of these previously for very simple functions, however the function i'm trying to fit is basically a mixture of 3 functions A gaussian (which dominates at x=0) An exponential (which takes over post gaussian) and a constant which…
AW1991
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Non-linear regression using custom neural network in MatLab

I am very new to MatLab. I got a task for modelling non-linear regression using neural network in MatLab. I need to create a two-layer neural network where: The first layer is N neurons with sigmoid activation function. The second layer is…
Evgeny Eltishev
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variable selection in package earth R for MARS

I am working on a MARS model using earth package in R. I want to force all the variables in the model. I have 14 predictors but in the result, I am getting only 13 predictors. Below is my code. mdl <- earth(x,y,nprune=10000, nk=1000, degree=1,…
maverick
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Applying Linear regression for quadratic function

I am new to machine learning. For a sample formula , y= 5 + 10(x^2), I generated x and y values and applied linear regression for it. The theta1 and theta2 values I received was for a straight line with large cost. How do I modify linear regression…
Mallik
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Non-Linear Iteration in R with ln() function

I am very new to R and I would like to ask how to perform an iteration of a time series data using the formula below: ln(x) + x = constant, where x is the data taken from the time series. The limits of x is from zero to infinity, as long as the…
Jek Agustin
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