The three data files (picks_vconstant, rec_xyz, and src_xyz) are
described in chapter 11 of the notes, as is the basic statics estimation
problem.  The c code read_data.c shows how to read the files and produce
a sparse matrix and rhs.  To save you time I've already done this.  The
rhs and matrix are contained in the files rhs.paul and matrix.paul.

The matrix has 120760 nonzero elements.  The file matrix.paul is
organized by the nonzero elements followed by the row and column pointers.