HP-71B Equation Solver

[J-F Garnier]

(11-24-2021 06:17 PM)rprosperi Wrote:  There is a video (somewhere...) of Chris saying the SOLVIT program for the 41 by Ted Beers was another predecessor/source of inspiration for his multi-variable solver, though the UI necessarily is a bit different and the equations are entered in FOCAL, not algebraic strings. I've just recently acquired a copy of this and will be posting it soon.

In the cited section in the HP Journal, it is written:
"Paul Swadener implemented a version that would accomplish
this on several HP calculators. The variable was usually selected
by specifying a number corresponding to the occurrence of the
variable as it mapped to a register in an RPN program that
represented the equation"
I don't know these RPN versions, and actually know nothing about Paul Swadener, except he is mentioned in the article Acknowledgments as the "financial consultant" of the team.
Does anybody know more ?

J-F