method

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v1_9_1_378 - Show latest stable - 0 notes - Class: Matrix

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1_9_1_378 (-6)
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What's this?

*(m) public

Matrix multiplication.

Matrix[[2,4], [6,8]] * Matrix.identity(2)
  => 2 4
     6 8

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# File lib/matrix.rb, line 455
  def *(m) # m is matrix or vector or number
    case(m)
    when Numeric
      rows = @rows.collect {|row|
        row.collect {|e|
          e * m
        }
      }
      return Matrix.rows(rows, false)
    when Vector
      m = Matrix.column_vector(m)
      r = self * m
      return r.column(0)
    when Matrix
      Matrix.Raise ErrDimensionMismatch if column_size != m.row_size
    
      rows = (0 .. row_size - 1).collect {|i|
        (0 .. m.column_size - 1).collect {|j|
          vij = 0
          0.upto(column_size - 1) do |k|
            vij += self[i, k] * m[k, j]
          end
          vij
        }
      }
      return Matrix.rows(rows, false)
    else
      x, y = m.coerce(self)
      return x * y
    end
  end

*

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