code: public /**/double quality() {
          if( is64 ) {
              return DecompositionFactory_DDRM.quality((DMatrixRMaj)mat, (DMatrixRMaj)U.getMatrix(),
                      (DMatrixRMaj)W.getMatrix(), (DMatrixRMaj)V.transpose().getMatrix());
          } else {
              return DecompositionFactory_FDRM.quality((FMatrixRMaj)mat, (FMatrixRMaj)U.getMatrix(),
                      (FMatrixRMaj)W.getMatrix(), (FMatrixRMaj)V.transpose().getMatrix());        }
      }
docs: <p>
  Computes the quality of the computed decomposition.  A value close to or less than 1e-15
  is considered to be within machine precision.
  </p>
  
  <p>
  This function must be called before the original matrix has been modified or else it will
  produce meaningless results.
  </p>
  
  @return Quality of the decomposition.