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Full Version: In Homage to Peter Henrici
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Hi All,

A few months ago I started reading Peter Henrici's book "Computational Analysis with the HP-25 Pocket Calculator". The book contains very interesting programs that implement interesting algorithms. I am impressed how, the late Swiss mathematician, Henrici was able to push the HP-25 to the very limit. I have been translating some of his programs to HP-67 and HP-41C, allowing me more breathing space and the ability to generalize Henrici's program. The code does a lot and without the advantage of using subroutines. I guess Henrici wanted to target the lower-cost HP-25 calculator--perhaps barely affordable to students. I wish he did a version for the more expensive (especially for students) HP-67 or HP-41C--a project that needed much selling to the conservative publishers.

Henrici's wife has also written a similar book for the HP-33C (which I also have) and this book is a companion of "Essentials of Numerical Analysis", also by Henrici. The HP-33C version uses subroutines and is able to explore more interesting algorithms.

Among the books written for programmable calculators, Henrici's books for the HP-25 and HP-33C stand tall. If you have spare time to fiddle with old code (and even run it on the HP-25 emulator available on this site) then I encourage you to do so. It is also an interesting journey into cool computational algorithms.


It must be quite rare for a husband and wife to share such a narrowly-focused esoteric interest. Perhaps they met because of similar interests.

Good point ... and it makes me wonder who among them was the smart calculator coder! Perhaps Mrs Henrici??? Whoever it was, he or she sure pushed coding to the limit on the 25 and the 33C.

I got a copy of this book as a door prize at HHC 2010 and translated a few of the programs to run on a 15C. It was fun to play with these little gems.