* lib/matrix.rb: Matrix.zero can build rectangular matrices.

  Vector#r should be called #magnitude

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32280 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Wed Jun 29 10:13:12 2011  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
+
+	* lib/matrix.rb: Matrix.zero can build rectangular matrices.
+	  Vector#r should be called #magnitude
+
 Wed Jun 29 10:11:08 2011  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
 
 	* lib/matrix.rb: Add Matrix#diagonal?, hermitian?, normal?,

NEWS

@@ -168,10 +168,12 @@ with all sufficient information, see the ChangeLog file.
     * Matrix#unitary?
     * Matrix#upper_triangular?
     * Matrix#zero?
+    * Vector#magnitude
   * extended methods:
     * 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.zero can build rectangular matrices
 
 * net/http
   * SNI (Server Name Indication) supported for HTTPS. 

lib/matrix.rb

@@ -229,13 +229,14 @@ class << Matrix
   end
 
   #
-  # Creates an +n+ by +n+ zero matrix.
+  # Creates a zero matrix.
   #   Matrix.zero(2)
   #     => 0 0
   #        0 0
   #
-  def Matrix.zero(n)
-    Matrix.scalar(n, 0)
+  def Matrix.zero(row_size, column_size = row_size)
+    rows = Array.new(row_size){Array.new(column_size, 0)}
+    new rows, column_size
   end
 
   #
@@ -1723,9 +1724,10 @@ def map2(v, &block) # :yield: e1, e2
   # Returns the modulus (Pythagorean distance) of the vector.
   #   Vector[5,8,2].r => 9.643650761
   #
-  def r
+  def magnitude
     Math.sqrt(@elements.inject(0) {|v, e| v + e*e})
   end
+  alias r magnitude
 
   #--
   # CONVERTING