TauAndParameters_EstParmFunc_FBM {CoDaLoMic} | R Documentation |
Obtaining the value of tau and the estimate value of the rest of the parameters
Description
This function estimates the parameters of the FBM model.
Usage
TauAndParameters_EstParmFunc_FBM(
ttau = 30,
ridge.final,
Iter.EstParmFunc = 80,
especie,
EspecieMaxima,
Tt,
E,
seed = NULL
)
Arguments
ttau |
Number. We estimate de FBM model for the values of tau: 1, 2,..., ttau |
ridge.final |
Object of class "ridgelm". Values obtained with the ridge regression. |
Iter.EstParmFunc |
Number. Number of iterations. Default: 80 iterations. |
especie |
Matrix that contains at row i the bacterial taxa of bacteria i at all time points. The bacteria placed in the last row of the matrix will be used as reference in the alr transformation and will be at the denominator of the balance. |
EspecieMaxima |
Row in which the bacteria used as reference is in |
Tt |
Number of time points available |
E |
Number. Number of bacteria available. |
seed |
Number. Set a seed. Default |
Details
We give to the parameter tau the value 1,2,...,ttau
. We estimate the FBM model for all this values (using the function "Estimate_param_FBM")
and we select the value of tau that minimizes the AIC. The regression of this model is defined by
\mu_{it}=a_{i1}+a_{i2}\cdot\text{alr}(x_{i,(t-1)})+a_{i3}\cdot\text{Balance}(x_{i,(t-1)})\text{ for }i=1,\dots, D-1\text{ where } D \text{ is the number of bacteria}
Value
Returns a list with:
EstimateParameters: Vector with the estimated parameters, in the following order: a11,a12,a13, a21, a22,a23, ...a(D-1)1,a(D-1)2,a(D-1)3,tau. Where D is the number of bacterial species present in the matrix
especie
.AIC Number: Value of the AIC.
All.iter: Matrix. Each row has the parameters obtained in each iteration. The parameters are in the columns written in the same order that they are written in
Param.Estimates
. In this matrix we must observe that in the last iterations the values has really similar or equal values, if not, we need to increase the value ofIter.EstParmFunc
.
References
Creus-MartÃ, I., Moya, A., Santonja, F. J. (2021). A Dirichlet autoregressive model for the analysis of microbiota time-series data. Complexity, 2021, 1-16.
Examples
set.seed(123)
especie=t(gtools::rdirichlet(5,c(1,3,1)))
Tt=5
E=3
EspecieMaxima=3
ridge.final=ridgeregression(Tt,especie, E, EspecieMaxima)
ttau=10
Iter.EstParmFunc=10
TauAndParameters_EstParmFunc_FBM(ttau,ridge.final,Iter.EstParmFunc, especie,EspecieMaxima,Tt,E,714)