Have you seen the work of Sergey Bochkanov ALGLIB Project --- for the LMA - give it a read/try:
Thanks Luis,
Yes I did see it and it is well done.
Right now concentrating to get something going, so I am translating that Python implementation.
After that with help from the gurus here maybe optimize it and then includes those nice to have like
so called geodesic acceleration etc.
But we are in the wrong thread.
ymg