Iota Array Class

An AbstractArray representing an integer sequence. Usually created by nv_iota() / nv_seq(), which both call prim_iota() internally. Inherits from AbstractArray.

Usage

IotaArray(shape, dtype, dimension, start = 1L, ambiguous = FALSE)

Arguments

shape

(stablehlo::Shape | integer())
The shape of the array.

dtype

(tengen::DataType)
The data type.

dimension

(integer(1))
The dimension along which values increase.

start

(integer(1))
The starting value.

ambiguous

(logical(1))
Whether the type is ambiguous. Ambiguous types usually arise from R literals (e.g., 1L, 1.0) and follow special promotion rules. See the vignette("type-promotion") for more details.

Lowering

When lowering to stableHLO, these become iota operations that generate the integer sequence so they do not need to actually hold the data in the executable, similar to ALTREPs in R. It lowers to stablehlo::hlo_iota(), optionally shifting the starting value via stablehlo::hlo_add().

Examples

x <- IotaArray(shape = 4L, dtype = "i32", dimension = 1L)
x
#> IotaArray(shape=(4), dtype=i32, dimension=1, start=1) 
ambiguous(x)
#> [1] FALSE
shape(x)
#> [1] 4
ndims(x)
#> [1] 1
dtype(x)
#> <i32>
# How it appears during tracing:
graph <- trace_fn(function() nv_iota(dim = 1L, dtype = "i32", shape = 4L), list())
graph
#> <AnvlGraph>
#>   Inputs: (none)
#>   Body:
#>     %1: i32[4] = iota [dim = 1, dtype = i32, shape = 4, start = 1, ambiguous = FALSE] ()
#>   Outputs:
#>     %1: i32[4] 
graph$outputs[[1]]$aval
#> IotaArray(shape=(4), dtype=i32, dimension=1, start=1)