code: @Override
      public boolean setA(DMatrixRMaj A) {
          if( A.numRows > maxRows ) {
              setMaxSize(A.numRows);
          }
  
          _setA(A);
          if( !decomposer.decompose(A) )
              return false;
          
          gammas = decomposer.getGammas();
          QR = decomposer.getQR();
  
          return true;
      }
docs: Performs QR decomposition on A
  
  @param A not modified.