method

permutation?

Ruby latest stable (v2_5_5) - 0 notes - Class: Matrix

1_8_6_287
1_8_7_72
1_8_7_330
1_9_1_378
1_9_2_180
1_9_3_125 (0)
1_9_3_392 (0)
2_1_10 (0)
2_2_9 (0)
2_4_6 (0)
2_5_5 (0)
2_6_3
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permutation?() public

Returns true if this is a permutation matrix Raises an error if matrix is not square.

# File lib/matrix.rb, line 745
  def permutation?
    Matrix.Raise ErrDimensionMismatch unless square?
    cols = Array.new(column_count)
    rows.each_with_index do |row, i|
      found = false
      row.each_with_index do |e, j|
        if e == 1
          return false if found || cols[j]
          found = cols[j] = true
        elsif e != 0
          return false
        end
      end
      return false unless found
    end
    true
  end

permutation?

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