docs: public static void subvector(DMatrix1Row A, int rowA, int colA, int length , boolean row, int offsetV, DMatrix1Row v) {
          if( row ) {
              for( int i = 0; i < length; i++ ) {
                  v.set( offsetV +i , A.get(rowA,colA+i) );
              }
          } else {
              for( int i = 0; i < length; i++ ) {
                  v.set( offsetV +i , A.get(rowA+i,colA));
              }
          }
      }