new

# File lib/matrix.rb, line 356
  def initialize(rows, column_count = rows[0].size)
    # No checking is done at this point. rows must be an Array of Arrays.
    # column_count must be the size of the first row, if there is one,
    # otherwise it *must* be specified and can be any integer >= 0
    @rows = rows
    @column_count = column_count
  end