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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 function pointer.

library(RsimdDispatch)

x <- as.raw(c(0, 1, 2, 0, 255))
count_nonzero(x)
#> [1] 3
simd_backend()
#> [1] "avx2"

Inspect the installed build:

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

Switching is allowed in the same R process:

simd_set_backend("scalar")
count_nonzero(x)
#> [1] 3

candidate <- setdiff(simd_info()$available_backends, "scalar")[1]
if (!is.na(candidate)) {
  simd_set_backend(candidate)
  count_nonzero(x)
}
#> [1] 3

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.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.