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fixed scalarIndexing performance issue #1215

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fixed scalarIndexing performance issue #1215

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bb26418
fixed scalarIndexing performance issue
riteshbhirud Jul 8, 2025
04a3d05
reduced allocations for NaNs
riteshbhirud Jul 8, 2025
da7e61f
run_formatter
riteshbhirud Jul 22, 2025
3aa4e66
Merge branch 'CliMA:main' into main
riteshbhirud Jul 22, 2025
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12 changes: 5 additions & 7 deletions src/shared_utilities/utils.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -593,13 +593,12 @@ function count_nans_state(
mask = nothing,
verbose = false,
)
# Note: this code uses `parent`; this pattern should not be replicated
num_nans = 0
ClimaComms.allowscalar(ClimaComms.device()) do
num_nans =
isnothing(mask) ? Int(sum(isnan.(parent(state)))) :
Int(sum(isnan.(parent(state)) .* parent(mask)))
if isnothing(mask)
num_nans = sum(@. ifelse(isnan(state), 1, 0))
else
num_nans = sum(@. ifelse(isnan(state), mask, 0))
end
num_nans = Int(num_nans)
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I think we can further optimize this and reduce some of the allocations. For the no mask case, we can go from 2 kernel launches to just one if we use mapreduce or count. I believe @kmdeck is correct, and line 597 will still allocate an intermediate. For the case with a mask, we can also get away with only one kernel launch and no allocations with mapreduce.

That could look something like

Suggested change
if isnothing(mask)
num_nans = sum(@. ifelse(isnan(state), 1, 0))
else
num_nans = sum(@. ifelse(isnan(state), mask, 0))
end
num_nans = Int(num_nans)
if isnothing(mask)
num_nans = count(isnan, parent(state)
else
num_nans = mapreduce((s, m) -> m != 0 && isnan(s), Base.add_sum, parent(state), parent(mask))
end

That would also avoid the type conversion.

I'm not sure if masks are guaranteed to be boolean valued, so I'm not sure if line 599 will always be valid

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@kmdeck kmdeck Jul 8, 2025 •
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nice!

The mask is not boolean, because we create it using this:

ClimaLand.jl/src/shared_utilities/Domains.jl

Line 1047 in 7ac4cd4

apply_threshold(field, value) =

I think we did this because you cant create a field of bools by broadcasting over a field of floats. But we can do something like:

apply_threshold(field, value) =
    field > value ? 0 : 1

and then later down in the landsea_mask function, change thishttps://github.com/CliMA/ClimaLand.jl/blob/7ac4cd452663559f20df22d2a60e8f1aaa92d90f/src/shared_utilities/Domains.jl#L1088

to

binary_mask = ClimaCore.Fields.Field(Bool, surface_space)
fill!(ClimaCore.Fields.field_values(binary_mask), 0)
@. binary_mask = apply_threshold(mask, threshold)

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One other thought is that we call this function for each state variable in Y, but with one exception, if one is NaN, the entire state is NaN at that same location. so maybe we can also speed it up by calling it for just one field.

I'm not sure how to do that in a nice automated way though, without making an assumption about what is in Y

if isapprox(num_nans, 0)
verbose && @info "No NaNs found"
else
Expand All @@ -608,7 +607,6 @@ function count_nans_state(
return nothing
end


"""
NaNCheckCallback(nancheck_frequency::Union{AbstractFloat, Dates.Period},
start_date, dt)
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