mark.tensor {tensorA} | R Documentation |
This modifies the names of the dimensions in a simple and reversible way by adding a mark.
mark(X,mark,...) ## S3 method for class 'tensor' mark(X,mark="'",i=1:level.tensor(X),...,by=NULL) ## S3 method for class 'numeric' mark(X,mark="'",i=1:length(X),...,by=NULL) ## S3 method for class 'character' mark(X,mark="'",i=1:length(X),...,by=NULL)
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. |
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.
A object similar to X but with marked dimensions.
K. Gerald van den Boogaart
# The outer product A <- to.tensor(1:4,c(a=2,b=2)) A