diff options
| -rw-r--r-- | ChangeLog | 4 | ||||
| -rw-r--r-- | NEWS | 1 | ||||
| -rw-r--r-- | lib/matrix.rb | 9 |
3 files changed, 11 insertions, 3 deletions
@@ -1,3 +1,7 @@ +Fri Jul 1 15:21:14 2011 Marc-Andre Lafortune <ruby-core@marc-andre.ca> + + * lib/matrix.rb: Allow non integer exponents for Matrix#** + Fri Jul 1 15:13:25 2011 Marc-Andre Lafortune <ruby-core@marc-andre.ca> * lib/matrix: Add Eigenvalue Decomposition @@ -178,6 +178,7 @@ with all sufficient information, see the ChangeLog file. * Matrix#each and #each_with_index can iterate on a subset of the elements * Matrix#find_index returns [row, column] and can iterate on a subset of the elements + * Matrix#** implements Numeric exponents (using the eigensystem) * Matrix.zero can build rectangular matrices * net/http diff --git a/lib/matrix.rb b/lib/matrix.rb index 8c6b3d6e87..5ce130221f 100644 --- a/lib/matrix.rb +++ b/lib/matrix.rb @@ -956,8 +956,10 @@ class Matrix private :inverse_from # - # Matrix exponentiation. Currently implemented for integer powers only. + # Matrix exponentiation. # Equivalent to multiplying the matrix by itself N times. + # Non integer exponents will be handled by diagonalizing the matrix. + # # Matrix[[7,6], [3,9]] ** 2 # => 67 96 # 48 99 @@ -977,8 +979,9 @@ class Matrix return z if (other >>= 1).zero? x *= x end - when Float, Rational - Matrix.Raise ErrOperationNotImplemented, "**", self.class, other.class + when Numeric + v, d, v_inv = eigensystem + v * Matrix.diagonal(*d.each(:diagonal).map{|e| e ** other}) * v_inv else Matrix.Raise ErrOperationNotDefined, "**", self.class, other.class end |