Getting Started with RsimdDispatch

RsimdDispatch demonstrates a single-shared-library runtime dispatch pattern for C code in R packages. The package stages scalar and SIMD kernel objects during configuration and switches among compiled, CPU-supported implementations through a guarded resolved operation table.

library(RsimdDispatch)

x <- as.raw(c(0, 1, 2, 0, 255))
a <- c(1, 2, 3)
b <- c(10, 100)
count_nonzero(x)
#> [1] 3
convolve1d(a, b)
#> [1]  10 120 230 300
simd_backend()
#> [1] "avx2"

Inspect the installed build:

simd_info()[c("compiled_backends", "available_backends", "operation_selected_backends")]
#> $compiled_backends
#> [1] "scalar" "sse2"   "sse41"  "avx2"   "avx512"
#> 
#> $available_backends
#> [1] "scalar" "sse2"   "sse41"  "avx2"  
#> 
#> $operation_selected_backends
#> count_nonzero    convolve1d 
#>        "avx2"        "avx2"

Switching is allowed in the same R process:

simd_set_backend("scalar")
count_nonzero(x)
#> [1] 3
convolve1d(a, b)
#> [1]  10 120 230 300

candidate <- setdiff(simd_info()$operation_backends$convolve1d, "scalar")[1]
if (!is.na(candidate)) {
  simd_set_backend(candidate)
  count_nonzero(x)
  convolve1d(a, b)
}
#> [1]  10 120 230 300

simd_set_backend("auto")
simd_backend()
#> [1] "avx2"

An explicit backend is accepted only when it was compiled and the current CPU/runtime supports it. Unsupported choices error before any ISA-specific code runs.