docs: public static long normEml(DMatrixRMaj mat , int numTrials) {
          long prev = System.currentTimeMillis();
  
          for( int i = 0; i < numTrials; i++ ) {
              NormOps_DDRM.normF(mat);
          }
  
          long curr = System.currentTimeMillis();
          return curr-prev;
      }