diff options
Diffstat (limited to 'lib/matrix.rb')
| -rw-r--r-- | lib/matrix.rb | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/matrix.rb b/lib/matrix.rb index 8c636f61e8..0a17678972 100644 --- a/lib/matrix.rb +++ b/lib/matrix.rb @@ -1458,6 +1458,35 @@ class Matrix rank end + # + # Returns a new matrix with rotated elements. + # The argument specifies the rotation (defaults to `:clockwise`): + # * :clockwise, 1, -3, etc.: "turn right" - first row becomes last column + # * :half_turn, 2, -2, etc.: first row becomes last row, elements in reverse order + # * :counter_clockwise, -1, 3: "turn left" - first row becomes first column + # (but with elements in reverse order) + # + # m = Matrix[ [1, 2], [3, 4] ] + # r = m.rotate_entries(:clockwise) + # # => Matrix[[3, 1], [4, 2]] + # + def rotate_entries(rotation = :clockwise) + rotation %= 4 if rotation.respond_to? :to_int + + case rotation + when 0 + dup + when 1, :clockwise + new_matrix @rows.transpose.each(&:reverse!), row_count + when 2, :half_turn + new_matrix @rows.map(&:reverse).reverse!, column_count + when 3, :counter_clockwise + new_matrix @rows.transpose.reverse!, row_count + else + raise ArgumentError, "expected #{rotation.inspect} to be one of :clockwise, :counter_clockwise, :half_turn or an integer" + end + end + # Returns a matrix with entries rounded to the given precision # (see Float#round) # |