Multi-dimension SArray is allocating huge memories at first time run

[islent]

using StaticArrays
a = rand(10,10);
b = rand(50,50);
c = rand(100,100);

@time SMatrix{10,10}(a)
@time SMatrix{50,50}(b)
@time SMatrix{100,100}(c)

Results:

julia> @time SMatrix{10,10}(a)
  0.136969 seconds (340.05 k allocations: 18.051 MiB, 99.78% compilation time)
10×10 SMatrix{10, 10, Float64, 100} with indices SOneTo(10)×SOneTo(10):
# Omit Array output

julia> @time SMatrix{50,50}(b)
  1.306580 seconds (1.87 M allocations: 64.299 MiB, 0.73% gc time, 99.98% compilation time)
50×50 SMatrix{50, 50, Float64, 2500} with indices SOneTo(50)×SOneTo(50):
# Omit Array output

julia> @time SMatrix{100,100}(c)
ERROR: syntax: invalid syntax (memory-error out of gc handles)
Stacktrace:
 [1] top-level scope
   @ REPL[7]:1

@time SMatrix{100,100}(c) runs a long time, and the memory occupation can reach ~ 4GB

Test environment:

(@v1.7) pkg> st StaticArrays
      Status `E:\.julia\environments\v1.7\Project.toml`
  [90137ffa] StaticArrays v1.2.13

julia> versioninfo()
Julia Version 1.7.0
Commit 3bf9d17731 (2021-11-30 12:12 UTC)
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: Intel(R) Xeon(R) W-10885M CPU @ 2.40GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-12.0.1 (ORCJIT, skylake)
Environment:
  JULIA_DEPOT_PATH = E:\.julia
  JULIA_NUM_THREADS = 1
  JULIA_EDITOR = code

[mateuszbaran]

This is a known issue. Due to the way StaticArrays.jl is designed, it is preferable to use normal arrays when the total length is more than roughly 50 to 500.

[islent]

Got it! I did not take notice of note in README:

Note that in the current implementation, working with large StaticArrays puts a lot of stress on the compiler, and becomes slower than Base.Array as the size increases. A very rough rule of thumb is that you should consider using a normal Array for arrays larger than 100 elements.

Will it be fixed in the future?

[mateuszbaran]

I doubt it. I wouldn't expect any significant development to happen in StaticArrays.jl (only bug fixing and minor features) and this is a big issue.

[islent]

Sad to hear that. Closing issue...