Questions tagged [starting-values]
Many computational statistical problems (including some estimation problems, such as fitting GLMs) cannot be solved in a single calculation step - their algorithms must be iterated repeatedly until convergence. Such algorithms need starting-values at the beginning of the algorithm.
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Non-linear regression. Need some help implementing a model from a paper
I found this paper very useful for my research, however, I'm not familiar with non-linear regressions and I'm finding it tricky replicating it.
Using the first f=model for example:
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Box-Cox power transformation, adding or subtracting constants, and interval scales
I am trying to understand how the Box-Cox power transformation works. So I took one of my datasets and ran the powerTransform function of the "car" package (via R Commander) after having computed a ...
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using own data as starting parameters for modeling
I'm currently having a heated debate with coworkers on whether it's acceptable to use estimates derived directly from the data as starting parameters for modeling.
For example, if I want to fit a ...
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Trouble fitting my data with non-linear Regression model
I have a dataset that contains tree height and diameter measurements among the tree stem. I tried to fit my data with GNLS in R, but I'm getting this "step halving factor reduced below minimum in NLS ...
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Initial conditions for nonlinear models using the nlsLM function
I have a data frame containing 70000 rows. For each row, I am trying to apply the nlsLM function (minpack.lm package) to find ...
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Specifying starting values/modes for K-modes Clustering
I have a very large data set with 9000 observations and 25 categorical variables, which I've transformed into binary data and preformed hierarchical clustering and K-modes clustering in R.
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Non linear regression - Von Bertalanffy Growth Function - Error: "singular gradient matrix at initial parameter estimates"
I am trying to estimate VBGF parameters K and Linf using non linear regression and nls(). First I used a classic approach where I estimate both parameters together as below with "alkdyr" being a ...
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Why is nls() giving me "singular gradient matrix at initial parameter estimates" errors?
I have some basic data on emission reductions and cost per car:
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MLE2 (in R): I can't find the right starting values
I am trying to fit several MLEs on a small dataset. I have managed to get it done for all my potential models except for this last one. This last one is actually the model that I expected to be the ...
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Exponential smoothing models backcasting and determining initial values python
I have made python code for exponential smoothing (ES) that takes in about 15 different cases including:
Simple Exponential Smoothing (SES)
Simple Seasonal models (both multiplicative and additive)
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How to choose initial values for nonlinear least squares fit
The question above says it all. Basically my question is for a generic fitting function (could be arbitrarily complicated) which will be nonlinear in the parameters I am trying to estimate, how does ...
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What are "starting values" in glm() function?
What are parameters start, etastart, mustart in the glm() function? I have been looking in ...
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