code: public INDArray convertBackToFeatures(INDArray data) {
          return Nd4j.tensorMmul(eigenvectors, data, new int[][] {{1}, {1}}).transposei().addiRowVector(mean);
      }
docs: Take the data that has been transformed to the principal components about the mean and
  transform it back into the original feature set.  Make sure to fill in zeroes in columns
  where components were dropped!
  @param data Data of the same features used to construct the PCA object but as the components
  @return The records in terms of the original features