docs: public double[] getBasisVector( int which ) {
          if( which < 0 || which >= numComponents )
              throw new IllegalArgumentException("Invalid component");
  
          DMatrixRMaj v = new DMatrixRMaj(1,A.numCols);
          CommonOps_DDRM.extract(V_t,which,which+1,0,A.numCols,v,0,0);
  
          return v.data;
      }