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Merged
ankane merged 1 commit into from
Nov 12, 2024
Merged

Sort features when receiving input as hash #9

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9 changes: 9 additions & 0 deletions lib/lightgbm/booster.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -141,6 +141,10 @@ def predict(input, start_iteration: nil, num_iteration: nil, **params)
input =
if daru?(input)
input.map_rows(&:to_a)
elsif input.is_a?(Hash) # sort feature.values to match the order of model.feature_name
sorted_feature_values(input)
elsif input.is_a?(Array) && input.first.is_a?(Hash) # on multiple elems, if 1st is hash, assume they all are
input.map(&method(:sorted_feature_values))
else
input.to_a
end
Expand Down Expand Up @@ -241,6 +245,11 @@ def read_int64(ptr)
ptr.read_array_of_int64(1).first
end

def sorted_feature_values(input_hash)
@cached_feature_names ||= feature_name
input_hash.transform_keys(&:to_s).fetch_values(*@cached_feature_names)
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@nunosilva800 nunosilva800 Oct 18, 2024

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I'm considering if accepting the input hash with keys as symbol or string is worth it, or if it should expect only strings.

Quick benchmark (10000 iterations):

                user     system      total        real
   keys are strings:  0.031401   0.001063   0.032464 (  0.032646)
with transform_keys:  0.108264   0.005040   0.113304 (  0.113892)
Suggested change
input_hash.transform_keys(&:to_s).fetch_values(*@cached_feature_names)
input_hash.fetch_values(*@cached_feature_names)

end

include Utils
end
end
16 changes: 16 additions & 0 deletions test/booster_test.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,22 @@ def test_feature_importance_bad_importance_type
assert_includes error.message, "Unknown importance type"
end

def test_predict_with_hash_builds_sorted_input
pred = booster.predict({x0: 3.7, x1: 1.2, x2: 7.2, x3: 9.0})
assert_in_delta 0.9823112229173586, pred

pred = booster.predict({"x3" => 9.0, "x2" => 7.2, "x1" => 1.2, "x0" => 3.7})
assert_in_delta 0.9823112229173586, pred

pred = booster.predict(
[
{"x3" => 9.0, "x2" => 7.2, "x1" => 1.2, "x0" => 3.7},
{"x3" => 0.0, "x2" => 7.9, "x1" => 0.5, "x0" => 7.5},
]
)
assert_elements_in_delta [0.9823112229173586, 0.9583143724610858], pred.first(2)
end

def test_model_to_string
assert booster.model_to_string
end
Expand Down