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L1 distance spec (single and batched evaluation)

Source: R/dist_l1.R
distance_l1.Rd

Returns a spec with eval() and eval_batch() closures for L1 distances. Compiled fast paths are used when available; otherwise R fallbacks are used.

Usage

distance_l1()

Value

A list with:

  • name: "l1"

  • eval(X, x0, ctx=NULL): numeric vector of length \(n\)

  • eval_batch(X, X0, ctx=NULL): numeric matrix \(n \times m\)

Batch evaluation

eval_batch(X, X0) expects an \(m \times p\) matrix of queries X0.

See also

distance_l1_scaled(), dist_l1(), dist_l1_scaled()

Examples

set.seed(3)
X <- matrix(rnorm(12), 4, 3)
X0 <- matrix(rnorm(6), 2, 3)
dspec <- distance_l1()
dspec$eval(X, X0[1, ])
#> [1] 0.5551521 2.7661406 1.2500104 1.5785391
dspec$eval_batch(X, X0)
#>           [,1]      [,2]
#> [1,] 0.5551521 2.2886396
#> [2,] 2.7661406 2.7985700
#> [3,] 1.2500104 0.4957488
#> [4,] 1.5785391 3.3120267