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Primitive Index of the Maximum

Source: R/primitives.R
prim_argmax.Rd

Returns the index of the maximum value along a single axis. Ties are broken by returning the smallest index.

Usage

prim_argmax(x, axis, drop = TRUE)

Arguments

x

(arrayish)
One input. Can be any data type. An R value materializes at its default data type.

axis

(integer(1))
Axis along which to find the index of the maximum. Negative values count from the end, i.e. -1 refers to the last axis.

drop

(logical(1))
If TRUE (default) the reduced axis is removed; if FALSE it is kept with size 1.

Value

(arrayish)
Has the default integer data type (see default_dtypes()) regardless of the input's, and the input's shape with axis removed (drop = TRUE) or set to 1 (drop = FALSE).

Implemented Rules

  • stablehlo

  • reverse

StableHLO

Lowers to hlo_reduce(), specified under reduce. The reduction is variadic over (values, indices), with a (value > value | (value == value & idx < idx)) selector.

See also

prim_argmin(), nv_argmax()

Examples

# the index comes out at the default integer data type
prim_argmax(nv_array(c(3, 1, 4, 1, 5)), axis = 1L)
#> AnvlArray
#>  5
#> [ CPUi32{} ]