Sparse Matrix format CRS I am study the format CRS of an sparse matrix. I have a doubt respect to the pointer row_ptr. What happend if the matrix has a row with all entries zero. Could you help to describe the row_ptr vector in the next case
\begin{bmatrix}
 2 &  0 & 0\\ 
 0 &  0 & 0\\ 
 0 & 0 & 1
\end{bmatrix}

The row vector is 
$$1,2,2,3$$
according to http://www.math.tamu.edu/~srobertp/Courses/Math639_2014_Sp/CRSDescription/CRSStuff.pdf.
Based on the reference, if row $i$ contains entirely zeros, you store in row-ptr($i$) the same as in row-ptr($i+1$). 
