From: Dave Baldwin <dave.baldwin@3dlabs.com>
Date: 2008-10-09T18:51:22+09:00
Subject: Bug in Vector class?

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require 'matrix'
m = Matrix.identity(4)
v = Vector[5, 6, 7, 1]
puts m * v

gives the expected answer of [5, 6, 7, 1]

but
puts v * m

gives
ExceptionForMatrix::ErrDimensionMismatch: Matrix dimension mismatch

because the Vector#* method promotes self to a column vector when the  
argument is found to be a Matrix.  I think it should be promoting self  
to a row vector and making this change removes the exception and gives  
the correct result.  The updated method is:

	def *(x)
	    	case x
	    		when Numeric
	      			els = @elements.collect{|e| e * x}
	      			Vector.elements(els, false)
	    		when Matrix
	      			Matrix.row_vector(self) * x
	    		else
	      			s, x = x.coerce(self)
	      			s * x
	    		end
   end


Dave.
  
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