code: public double[] sampleToEigenSpace(double[] sampleData) throws Exception {
  		if (!isPcaInitialized) {
  			// initiallize PCA correctly!
  			throw new Exception("PCA is not correctly initiallized!");
  		}
  		if (sampleData.length != sampleSize) {
  			throw new IllegalArgumentException("Unexpected vector length!");
  		}
  		DenseMatrix64F sample = new DenseMatrix64F(sampleSize, 1, true, sampleData);
  		DenseMatrix64F projectedSample = new DenseMatrix64F(numComponents, 1);
  		// mean subtraction
  		CommonOps.sub(sample, means, sample);
  		// projection
  		CommonOps.mult(V_t, sample, projectedSample);
  		// whitening
  		if (doWhitening) { // always perform this normalization step when whitening is used
  			return Normalization.normalizeL2(projectedSample.data);
  		} else {
  			return projectedSample.data;
  		}
  	}
docs: Converts a vector from sample space into eigen space. If {@link #doWhitening} is true, then the vector
  is also L2 normalized after projection.
  
  @param sampleData
  Sample space vector
  @return Eigen space projected vector
  @throws Exception