Automatic common backtransformation for compositions
Functions to automatically determine and compute the relevant back-transformation for a rmult object.
backtransform(x, as=x)
backtransform.rmult(x, as=x)
gsi.orig(x,y=NULL)
gsi.getV(x,y=NULL)x |
an rmult object to be backtransformed; for both |
as |
an rmult object previously obtained with any compositional transformation of this package. |
y |
for both |
The general idea of this package is to analyse the same data with different geometric concepts, in a fashion as similar as possible. For each of the four concepts there exists a family of transforms expressing the geometry in aan appropriate manner. Transformed data can be further analysed, and certain results may be back-transformed to the original scale. These functions take care of tracking, constructing and computing the inverse transformation, whichever was the original geometry and forward transformation used.
For functions backtransform or backtransform.rmult, a corresponding matrix or vector containing the backtransformation of x. \
For function gsi.orig, the original data with a compositional class, if it exists (or NULL otherwise). \
For function gsi.getV, the transposed, inverse matrix of log-contrasts originally used to forward transform the original composition orig to its coefficients/coordinates. If it does not exists, the output is NULL.
R. Tolosana-Delgado, K.Gerald v.d. Boogaart http://www.stat.boogaart.de
van den Boogaart, K.G. and R. Tolosana-Delgado (2008) "compositions": a unified R package to analyze Compositional Data, Computers & Geosciences, 34 (4), pages 320-338, doi: 10.1016/j.cageo.2006.11.017.
x <- acomp(1:5) x backtransform(ilr(x)) backtransform(clr(x)) backtransform(idt(x)) backtransform(cdt(x)) backtransform(alr(x))
Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.