Module: RMatrix::Indices

Included in:
Matrix
Defined in:
lib/rmatrix/indices.rb

Instance Method Summary collapse

Instance Method Details

#[](*args) ⇒ Object 



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# File 'lib/rmatrix/indices.rb', line 3

def [](*args)
  indices           = unmap_args(args)
  result_row_map    = build_result_map(self.row_map, indices.first, self.rows)      if self.row_map
  result_column_map = build_result_map(self.column_map, indices.last, self.columns) if self.column_map
  raw[*indices, column_map: result_column_map, row_map: result_row_map]
end

#build_result_map(existing, indices, size) ⇒ Object 



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# File 'lib/rmatrix/indices.rb', line 20

def build_result_map(existing, indices, size)
  return existing if indices == true
  result_map = {}
  indexify(indices, result_map, size)
  result_map.default_proc =  ->(h,k) do
    existing_index = existing[k]
    case existing_index
    when TrueClass
      existing_index
    when Range
      if existing_index.exclude_end?
        h[k] = h[existing_index.first]...h[existing_index.end]
      else
        h[k] = h[existing_index.first]..h[existing_index.end]
      end
    when nil
      raise "Couldn't find key #{k} in index mapping"
    else
      h[existing_index]
    end
  end
  result_map
end

#indexify(indices, results, size, total = 0) ⇒ Object 



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# File 'lib/rmatrix/indices.rb', line 44

def indexify(indices, results, size, total=0)
  Array(indices).each do |index|
    case index
    when TrueClass
      (0...size).each do |i|
        results[i] = i
      end
    when Fixnum
      results[index] ||= total
      total += 1
    when Array
      indexify(index, results, size, total)
    when Range
      inclusive  = index.exclude_end? ? index.first..(index.end - 1) : index
      flat_range = inclusive.end < inclusive.first ? [*inclusive.end..inclusive.first].reverse : [*inclusive]
      flat_range.each do |elm|
        indexify(elm, results, size, total)
      end
    end
  end
end

#raw ⇒ Object 



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# File 'lib/rmatrix/indices.rb', line 10

def raw
  @raw ||= begin
    raw = Struct.new(:narray, :typecode).new(self.narray, self.typecode)
    def raw.[](*args, column_map: nil, row_map: nil)
      args.all?{|x| Fixnum === x } ? narray[*args.reverse] : Matrix.new(narray[*args.reverse], typecode, column_map: column_map, row_map: row_map)
    end
    raw
  end
end

#unmap_args(args) ⇒ Object 



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# File 'lib/rmatrix/indices.rb', line 66

def unmap_args(args)
  if args.length == 1
    if row_map
      return [unmap_index(self.row_map, args[0]), true] rescue nil
    end
    if column_map
      return [true, [unmap_index(self.column_map, args[0])]] rescue nil
    end
    return [args[0]]
  else
    [
      self.row_map ? unmap_index(self.row_map, args[0]) : args[0],
      Array(self.column_map ? unmap_index(self.column_map, args[1]) : args[1])
    ]
  end
end

#unmap_index(map, columns) ⇒ Object 



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# File 'lib/rmatrix/indices.rb', line 83

def unmap_index(map, columns)
  case columns
  when TrueClass, FalseClass
    columns
  when Array
    columns.map{|col| unmap_index(map, col)}.flatten
  when Range
    first = unmap_index(map, columns.first)
    last = unmap_index(map, columns.end)
    first = Range === first ? first.first : first
    if columns.exclude_end?
      last = Range === last ? last.first : last
      first...last
    else
      last = Range === last ? last.end : last
      first..last
    end
  else
    index = map[columns]
    raise "Value not present in index mapping: #{columns}" unless index
    index
  end
end