gistfile1.rb

class Warshall
 def initialize(adjacencyMatrix)
  @adjacencyMatrix=adjacencyMatrix
 end
 
 def getPathMatrix
  numNodes=@adjacencyMatrix[0].length
  pathMatrix=Array.new(@adjacencyMatrix)
  for k in 0...numNodes
   for i in 0...numNodes
    #Optimization: if no path from i to k, no need to test k to j
    if pathMatrix[i][k]==1 then 
     for j in 0...numNodes
      if pathMatrix[k][j]==1 then
       pathMatrix[i][j]=1
      end
     end
    end
   end
  end
  return pathMatrix
 end

Your optimization is not working. All jumps across 2 nodes (searching for path from a -> d in graph a -> b, b -> c, c ->d) will fail.