Description Usage Arguments Details Value Missing Policy Author(s) References See Also Examples

Groups parts by amalgamation or balancing of their amounts or proportions.

1 2 3 4 5 6 7 8 9 10 11 12 | ```
groupparts(x,...)
## S3 method for class 'acomp'
groupparts(x,...,groups=list(...))
## S3 method for class 'rcomp'
groupparts(x,...,groups=list(...))
## S3 method for class 'aplus'
groupparts(x,...,groups=list(...))
## S3 method for class 'rplus'
groupparts(x,...,groups=list(...))
## S3 method for class 'ccomp'
groupparts(x,...,groups=list(...))
``` |

`x` |
an amount/compositional dataset |

`...` |
further parameters to use (actually ignored) |

`groups` |
a list of numeric xor character vectors, each giving a group of parts |

In the real geometry grouping is done by amalgamation (i.e. adding the parts). In the Aitchison-geometry grouping is done by taking geometric means. The new parts are named by named formal arguments. Not-mentioned parts remain ungrouped.

a new dataset of the same type with each group represented by a single column

For the real geometries, SZ and BDL are considered as 0, and MAR and MNAR are kept as missing of the same type. For the relative geometries, a BDL is a special kind of MNAR, whereas a SZ is qualitatively different (thus a balance with a SZ has no sense). MAR values transfer their MAR property to the resulting new variable.

K.Gerald v.d. Boogaart http://www.stat.boogaart.de, Raimon Tolosana-Delgado

Egozcue, J.J. and V. Pawlowsky-Glahn (2005) Groups of Parts and their Balances in Compositional Data Analysis, Mathematical Geology, in press

1 2 3 4 5 | ```
data(SimulatedAmounts)
plot(groupparts(acomp(sa.lognormals5),A=c(1,2),B=c(3,4),C=5))
plot(groupparts(aplus(sa.lognormals5),B=c(3,4),C=5))
plot(groupparts(rcomp(sa.lognormals5),A=c("Cu","Pb"),B=c(2,5)))
hist(groupparts(rplus(sa.lognormals5),1:5))
``` |

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