michel2323 commented 2 years ago

Removed undef everywhere. Uninitialized variables can lead to bugs in the derivatives that are very hard to debug. I would be in favor or not using undef as a matter of style.

codecov-commenter commented 2 years ago

Codecov Report

Merging #249 (bc65d1b) into master (be0d4e7) will decrease coverage by 0.04%. The diff coverage is 80.95%.

@@            Coverage Diff             @@
##           master     #249      +/-   ##
==========================================
- Coverage   75.62%   75.57%   -0.05%     
==========================================
  Files          28       28              
  Lines        3462     3456       -6     
==========================================
- Hits         2618     2612       -6     
  Misses        844      844

Impacted Files	Coverage Δ
src/PowerSystem/parsers/parse_con.jl	`0.00% <0.00%> (ø)`
src/PowerSystem/parsers/parse_rop.jl	`0.00% <0.00%> (ø)`
src/LinearSolvers/preconditioners.jl	`81.92% <100.00%> (-0.21%)`	:arrow_down:
src/Polar/functions.jl	`95.96% <100.00%> (ø)`
src/Polar/newton.jl	`86.79% <100.00%> (ø)`
src/Polar/stacks.jl	`100.00% <100.00%> (ø)`
src/PowerSystem/parsers/parse_psse.jl	`100.00% <100.00%> (ø)`
src/PowerSystem/parsers/parse_raw.jl	`95.50% <100.00%> (ø)`

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michel2323 commented 2 years ago

@frapac With

using CUDA
using BenchmarkTools
AT = CuArray{Float64}

function exalloc(VD::Type, dims...)
    arr = VD(undef, dims...)
    fill!(arr, zero(eltype(VD)))
    return arr
end

@btime cux1 = exalloc(AT, (10,))
@btime cux2 = CuArray(zeros(eltype(AT),10))

I get:

  5.161 μs (29 allocations: 1.23 KiB)
  6.669 μs (5 allocations: 304 bytes)

I think the GC and CUDA.jl are smarter than that, no? Maybe, we don't need the fill!.

This leads to the same number of allocations though:

@inline function exalloc(VD::Type, dims...)
    arr = VD(zeros(eltype(VD),dims...))
    return arr
end

However, I admit, I'm not a fan of adding another layer just for that, even if it adds duplicates throughout the code.

michel2323 commented 2 years ago

Revisit some other time I'd say.

exanauts / ExaPF.jl

Get rid of uninitialized Arrays #249

Codecov Report