Returns the names of all currently registered eltwise operations.
Examples
head(registered_eltwise())
#> [1] "Abs" "Clamp" "Clamp01" "Convert" "Exp" "Fraction"
register_eltwise("Negate_example", function(x, ...) -x, overwrite = TRUE)
"Negate_example" %in% registered_eltwise()
#> [1] TRUE