code: public DataBuffer getIndicesOf(int i) {
          int from = underlyingRank() * i;
          int to = from + underlyingRank(); //not included
  
          int[] arr = new int[rank];
          int j = 0; // iterator over underlying indices
          int k = 0; //iterator over hiddenIdx
          for (int dim = 0; dim < rank; dim++) {
              if (k < hiddenDimensions().length && hiddenDimensions()[k] == j) {
                  arr[dim] = 0;
                  k++;
              } else {
                  arr[dim] = indices.getInt(j);
                  j++;
              }
          }
          return Nd4j.getDataBufferFactory().createInt(arr);
      }
docs: Returns the indices of the element of the given index in the array context
  
  @param i the index of the element
  @return a dataBuffer containing the indices of element