model.EM {EMMAgeo} R Documentation

## Model all possible end-member scenarios

### Description

This function takes a definition of weight transformation limits and corresponding minimum and maximum numbers of end-members to model all end-member scenarios in accordance with these parameters. Based on the output the user can decide on robust end-members.

### Usage

model.EM(X, q, l, classunits, plot = TRUE, col.q = TRUE, bw, ...)


### Arguments

 X Numeric matrix, input data set with m samples (rows) and n variables (columns). q Numeric matrix, definitions of minimum and maximum number of end-members (cf. get.q()), required. l Numeric vector, weight transformation limit values, corresponding to the matrix q, required. classunits Numeric vector, optional class units (e.g. micrometers or phi-units) of the same length as columns of X. plot Logical scalar, option to plot the results (cf. details for explanations), default is TRUE. col.q Logical scalar, option to colour end-member loadings by the number of end-members which were used to create the model realisation, default is TRUE. bw Numeric scalar, optional manual setting of the kde bandwidth. By default, bw is calculated as 1 percent of the number of grain-size classes. ... Further arguments passed to the function.

### Details

The plot output is an overlay of several data. The coloured lines in the background are end-member loadings (number noted in the plot title), resulting from all possible model scenarios. If col.q == TRUE they are coloured according to the number of end-members with which the model was generated. This colour scheme allows to depict end-members that emerge for model realisations with specific number of end-members. The thick black line is a kernel density estimate curve, generated from the mode positions of all end-members. The kernel bandwidth is set to 1 percent of the number of grain-size classes of the input data set, which gave useful results for most of our test data sets. The cumulaitve dot-line-plot is a further visualisation of end-member mode positions. The function is a modified wrapper function for the function test.robustness().

### Value

List object with all modelled end-members, each described by input parameters, mode position, quality measures and value distributions.

### Author(s)

Michael Dietze, Elisabeth Dietze

### References

Dietze E, Hartmann K, Diekmann B, IJmker J, Lehmkuhl F, Opitz S, Stauch G, Wuennemann B, Borchers A. 2012. An end-member algorithm for deciphering modern detrital processes from lake sediments of Lake Donggi Cona, NE Tibetan Plateau, China. Sedimentary Geology 243-244: 169-180.

EMMA, test.l.max

### Examples