Functions to get or set the names of the dimensions of an array.

index(x)

index(x) <- value

Arguments

x

array.

value

vector of indices.

Value

Vector of indices.

Functions

  • index<-: set indices.

References

Guidotti, E. (2020). "calculus: High dimensional numerical and symbolic calculus in R". https://arxiv.org/abs/2101.00086

See also

Other tensor algebra: contraction(), delta(), diagonal(), einstein(), epsilon()

Examples

### array with no indices x <- array(1, dim = c(1, 3, 2)) index(x)
#> NULL
### indices on initialization x <- array(1, dim = c(i=1, j=3, k=2)) index(x)
#> [1] "i" "j" "k"
### set indices on the fly x <- array(1, dim = c(1, 3, 2)) index(x) <- c("i", "j", "k") index(x)
#> [1] "i" "j" "k"