title: Converting from COO to Compressed sparse matrix
body: <p>I wanted CSR files preferably from matrix market for my OpenCL library, I searched a lot for CSR generators in C but didn't get any. I find matrix market formats comfortable since they have defined the functions for read and write. I'm also curious how CUSP library in CUDA C is able to read COO matrix from an .mtx file and can convert it to CSR format. Thanks in advance</p>