docs: public double[] sampleToEigenSpace( double[] sampleData ) {
          if( sampleData.length != A.getNumCols() )
              throw new IllegalArgumentException("Unexpected sample length");
          DMatrixRMaj mean = DMatrixRMaj.wrap(A.getNumCols(),1,this.mean);
  
          DMatrixRMaj s = new DMatrixRMaj(A.getNumCols(),1,true,sampleData);
          DMatrixRMaj r = new DMatrixRMaj(numComponents,1);
  
          CommonOps_DDRM.subtract(s, mean, s);
  
          CommonOps_DDRM.mult(V_t,s,r);
  
          return r.data;
      }