Class: XGBoost::Booster

Inherits:
Object
  • Object
show all
Includes:
Utils
Defined in:
lib/xgboost/booster.rb

Instance Method Summary collapse

Constructor Details

#initialize(params: nil, cache: nil, model_file: nil) ⇒ Booster

Returns a new instance of Booster.



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# File 'lib/xgboost/booster.rb', line 5

def initialize(params: nil, cache: nil, model_file: nil)
  cache ||= []
  cache.each do |d|
    if !d.is_a?(DMatrix)
      raise TypeError, "invalid cache item: #{d.class.name}"
    end
  end

  dmats = array_of_pointers(cache.map { |d| d.handle })
  out = ::FFI::MemoryPointer.new(:pointer)
  check_call FFI.XGBoosterCreate(dmats, cache.length, out)
  @handle = ::FFI::AutoPointer.new(out.read_pointer, FFI.method(:XGBoosterFree))

  cache.each do |d|
    assign_dmatrix_features(d)
  end

  if model_file
    check_call FFI.XGBoosterLoadModel(handle, model_file)
  end

  set_param(params)
end

Instance Method Details

#[](key_name) ⇒ Object

Raises:

  • (TypeError) 


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# File 'lib/xgboost/booster.rb', line 29

def [](key_name)
  if key_name.is_a?(String)
    return attr(key_name)
  end

  # TODO slice

  raise TypeError, "expected string"
end

#[]=(key_name, raw_value) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 39

def []=(key_name, raw_value)
  set_attr(**{key_name => raw_value})
end

#attr(key) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 55

def attr(key)
  ret = ::FFI::MemoryPointer.new(:pointer)
  success = ::FFI::MemoryPointer.new(:int)
  check_call FFI.XGBoosterGetAttr(handle, key.to_s, ret, success)
  success.read_int != 0 ? ret.read_pointer.read_string : nil
end

#attributes ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 62

def attributes
  length = ::FFI::MemoryPointer.new(:uint64)
  sarr = ::FFI::MemoryPointer.new(:pointer)
  check_call FFI.XGBoosterGetAttrNames(handle, length, sarr)
  attr_names = from_cstr_to_rbstr(sarr, length)
  attr_names.to_h { |n| [n, attr(n)] }
end

#best_iteration ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 132

def best_iteration
  attr(:best_iteration)&.to_i
end

#best_iteration=(iteration) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 136

def best_iteration=(iteration)
  set_attr(best_iteration: iteration)
end

#best_score ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 140

def best_score
  attr(:best_score)&.to_f
end

#best_score=(score) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 144

def best_score=(score)
  set_attr(best_score: score)
end

#dump(fmap: "", with_stats: false, dump_format: "text") ⇒ Object

returns an array of strings



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# File 'lib/xgboost/booster.rb', line 180

def dump(fmap: "", with_stats: false, dump_format: "text")
  out_len = ::FFI::MemoryPointer.new(:uint64)
  out_result = ::FFI::MemoryPointer.new(:pointer)

  names = feature_names || []
  fnames = array_of_pointers(names.map { |fname| string_pointer(fname) })
  ftypes = array_of_pointers(feature_types || Array.new(names.size, string_pointer("float")))

  check_call FFI.XGBoosterDumpModelExWithFeatures(handle, names.size, fnames, ftypes, with_stats ? 1 : 0, dump_format, out_len, out_result)

  out_result.read_pointer.get_array_of_string(0, out_len.read_uint64)
end

#dump_model(fout, fmap: "", with_stats: false, dump_format: "text") ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 160

def dump_model(fout, fmap: "", with_stats: false, dump_format: "text")
  ret = dump(fmap: fmap, with_stats: with_stats, dump_format: dump_format)
  File.open(fout, "wb") do |f|
    if dump_format == "json"
      f.print("[\n")
      ret.each_with_index do |r, i|
        f.print(r)
        f.print(",\n") if i < ret.size - 1
      end
      f.print("\n]")
    else
      ret.each_with_index do |r, i|
        f.print("booster[#{i}]:\n")
        f.print(r)
      end
    end
  end
end

#eval_set(evals, iteration) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 106

def eval_set(evals, iteration)
  dmats = array_of_pointers(evals.map { |v| v[0].handle })
  evnames = array_of_pointers(evals.map { |v| string_pointer(v[1]) })

  out_result = ::FFI::MemoryPointer.new(:pointer)

  check_call FFI.XGBoosterEvalOneIter(handle, iteration, dmats, evnames, evals.size, out_result)

  out_result.read_pointer.read_string
end

#feature_names ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 84

def feature_names
  get_feature_info("feature_name")
end

#feature_names=(features) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 88

def feature_names=(features)
  set_feature_info(features, "feature_name")
end

#feature_types ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 76

def feature_types
  get_feature_info("feature_type")
end

#feature_types=(features) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 80

def feature_types=(features)
  set_feature_info(features, "feature_type")
end

#fscore(fmap: "") ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 193

def fscore(fmap: "")
  # always weight
  score(fmap: fmap, importance_type: "weight")
end

#num_boosted_rounds ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 148

def num_boosted_rounds
  rounds = ::FFI::MemoryPointer.new(:int)
  check_call FFI.XGBoosterBoostedRounds(handle, rounds)
  rounds.read_int
end

#num_features ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 154

def num_features
  features = ::FFI::MemoryPointer.new(:uint64)
  check_call FFI.XGBoosterGetNumFeature(handle, features)
  features.read_uint64
end

#predict(data, ntree_limit: nil) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 117

def predict(data, ntree_limit: nil)
  ntree_limit ||= 0
  out_len = ::FFI::MemoryPointer.new(:uint64)
  out_result = ::FFI::MemoryPointer.new(:pointer)
  check_call FFI.XGBoosterPredict(handle, data.handle, 0, ntree_limit, 0, out_len, out_result)
  out = out_result.read_pointer.read_array_of_float(out_len.read_uint64)
  num_class = out.size / data.num_row
  out = out.each_slice(num_class).to_a if num_class > 1
  out
end

#reset ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 50

def reset
  check_call FFI.XGBoosterReset(handle)
  self
end

#save_config ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 43

def save_config
  length = ::FFI::MemoryPointer.new(:uint64)
  json_string = ::FFI::MemoryPointer.new(:pointer)
  check_call FFI.XGBoosterSaveJsonConfig(handle, length, json_string)
  json_string.read_pointer.read_string(length.read_uint64).force_encoding(Encoding::UTF_8)
end

#save_model(fname) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 128

def save_model(fname)
  check_call FFI.XGBoosterSaveModel(handle, fname)
end

#score(fmap: "", importance_type: "weight") ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 198

def score(fmap: "", importance_type: "weight")
  if importance_type == "weight"
    trees = dump(fmap: fmap, with_stats: false)
    fmap = {}
    trees.each do |tree|
      tree.split("\n").each do |line|
        arr = line.split("[")
        next if arr.size == 1

        fid = arr[1].split("]")[0].split("<")[0]
        fmap[fid] ||= 0
        fmap[fid] += 1
      end
    end
    fmap
  else
    average_over_splits = true
    if importance_type == "total_gain"
      importance_type = "gain"
      average_over_splits = false
    elsif importance_type == "total_cover"
      importance_type = "cover"
      average_over_splits = false
    end

    trees = dump(fmap: fmap, with_stats: true)

    importance_type += "="
    fmap = {}
    gmap = {}
    trees.each do |tree|
      tree.split("\n").each do |line|
        arr = line.split("[")
        next if arr.size == 1

        fid = arr[1].split("]")

        g = fid[1].split(importance_type)[1].split(",")[0].to_f

        fid = fid[0].split("<")[0]

        fmap[fid] ||= 0
        gmap[fid] ||= 0

        fmap[fid] += 1
        gmap[fid] += g
      end
    end

    if average_over_splits
      gmap.each_key do |fid|
        gmap[fid] = gmap[fid] / fmap[fid]
      end
    end

    gmap
  end
end

#set_attr(**kwargs) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 70

def set_attr(**kwargs)
  kwargs.each do |key, value|
    check_call FFI.XGBoosterSetAttr(handle, key.to_s, value&.to_s)
  end
end

#set_param(params, value = nil) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 92

def set_param(params, value = nil)
  if params.is_a?(Enumerable)
    params.each do |k, v|
      check_call FFI.XGBoosterSetParam(handle, k.to_s, v.to_s)
    end
  else
    check_call FFI.XGBoosterSetParam(handle, params.to_s, value.to_s)
  end
end

#update(dtrain, iteration) ⇒ Object 



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# File 'lib/xgboost/booster.rb', line 102

def update(dtrain, iteration)
  check_call FFI.XGBoosterUpdateOneIter(handle, iteration, dtrain.handle)
end