code: public static double innerProdRow(int blockLength,
                                        DSubmatrixD1 A,
                                        int rowA,
                                        DSubmatrixD1 B,
                                        int rowB, int zeroOffset ) {
          int offset = rowA + zeroOffset;
          if( offset + B.col0 >= B.col1 )
              return 0;
  
          // take in account the one in 'A'
          double total = B.get(rowB,offset);
  
          total += VectorOps_DDRB.dot_row(blockLength,A,rowA,B,rowB,offset+1,A.col1-A.col0);
  
          return total;
      }
docs: <p>
  Computes the inner product of row vector 'rowA' against row vector 'rowB' while taking account leading zeros and one.<br>
  <br>
  ret = a<sup>T</sup>*b
  </p>
  
  <p>
  Row A is assumed to be a householder vector.  Element at 'colStartA' is one and previous elements are zero.
  </p>
  
  @param blockLength
  @param A block aligned submatrix.
  @param rowA Row index inside the sub-matrix of first row vector has zeros and ones..
  @param rowB Row index inside the sub-matrix of second row vector.
  @return dot product of the two vectors.