Added support for Rover data frames to predict method

Author: ankane

CHANGELOG.md

@@ -1,6 +1,6 @@
 ## 0.4.0 (unreleased)
 
-- Added support for hashes to `predict` method
+- Added support for hashes and Rover data frames to `predict` method
 - Changed `Dataset` to use column names for feature names with Rover and Daru
 - Dropped support for Ruby < 3.1
 

lib/lightgbm/booster.rb

@@ -146,6 +146,9 @@ def predict(input, start_iteration: nil, num_iteration: nil, **params)
           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))
+        elsif rover?(input)
+          # TODO improve performance
+          input[feature_name()].to_numo.to_a
         else
           input.to_a
         end

test/booster_test.rb

@@ -50,6 +50,17 @@ def test_predict_hash
     end
   end
 
+  def test_predict_rover
+    require "rover"
+    x_test =
+      Rover::DataFrame.new([
+        {"x3" => 9.0, "x2" => 7.2, "x1" => 1.2, "x0" => 3.7},
+        {"x3" => 0.0, "x2" => 7.9, "x1" => 0.5, "x0" => 7.5},
+      ])
+    pred = booster.predict(x_test)
+    assert_elements_in_delta [0.9823112229173586, 0.9583143724610858], pred.first(2)
+  end
+
   def test_model_to_string
     assert booster.model_to_string
   end