mark.tensor: Marks the names of a tensor with a mark
Description
This modifies the names of the dimensions in a simple and reversible
way by adding a mark.
Usage
mark(X,mark,...)
# S3 method for tensor
mark(X,mark="'",i=1:level.tensor(X),...,by=NULL)
# S3 method for numeric
mark(X,mark="'",i=1:length(X),...,by=NULL)
# S3 method for character
mark(X,mark="'",i=1:length(X),...,by=NULL)
Value
A object similar to X but with marked dimensions.
Arguments
X
A tensor or dimension to be marked
mark
a character giving the mark
i
the dimensions to be marked
...
generic arguments
by
Dimensions not to be marked. Wins in case of conflicts.
Author
K. Gerald van den Boogaart
Details
The concept is very important in tensor algebra since it allows to
keep dimensions connected without but still
distinguishable. Eventually later a function for the Riemann summing
rule will make use of marks to distinguish covariate and contravariate
dimensions.