Macros that customize the sparse matrix routines. Macros and declarations to be imported by the user. See the reference in spRevision. Pointer to matrix. RHS is the input data array, the right hand side.
Solution is the output data array.
This data is undisturbed and may be reused for other solves. Pointer that points to current pivot or diagonal element. Size of matrix. Made local to reduce indirection. Temporary storage for entries in arrays.