submatrix

//submatrix determination for calculating determinants of matrices
  def submatrix(i : Int, j : Int, matrix : Array[Array]) = {
    //returns a new array of size n-1 with the ith index removed
    def removeIndex(index : Int, arr: Array): Array = {
      arr
        .zipWithIndex //what you call if you need an indexed loop
        .filter{ case (_,index) => index != r }
        .map { case (value, _) => value }
    }
    removeIndex(i , matrix.map{ case row => removeIndex(j, row) } )
  }