| diag_ext | Internal function to generate diagonal matrices with possibly an offset with possibly mirrored diagonal |
| fredholm_solve | Solve a Fredholm equation of the first and second kind |
| indexing | Internal function to convert (row,col) to vector index |
| makeH | Make H Matrix as in (Twomey 1963) |
| simpson | Internal function to calculate integration weights for Simpson's rule |
| smooth | Internal function to smooth a vector of values using two-point average |
| volterra_solve | Solve a Volterra equation of the first kind |
| volterra_solve2 | Solve a Volterra equation of the second kind |