Prime and Saturn calculators

[dm319]

(07-06-2024 12:03 AM)dm319 Wrote:  I've heard that about the 12-c platinum and Kinpo, but I find it hard to believe.

Been thinking about this more. Puzzle 4 is N = 480, I%YR = 0, PV = 100'000, FV = 0, solve for PMT. Then take result, put back into PMT, and attempt to calculate Interest rate, which should be 0.

These the results for puzzle 4:

Code:

| calculator                  | 4                                       |
|-----------------------------|-----------------------------------------|
| HP-80                       | ERR                                     |
| HP-70                       | -1.03950104e-9                          |
| HP-27                       | -1.039501039e-9                         |
| HP-22                       | -1.03950104e-9                          |
| HP-41CX Financial Decisions | 0                                       |
| HP-92                       | 0                                       |
| HP-37E                      | -1e-9                                   |
| HP-38E                      | -1e-9                                   |
| HP-12c                      | -7.983367984e-10                        |
| HP-12cp                     | -7.98336798336e-12                      |
| HP-12c comma                | ERR                                     |
| HP-10bII+                   | -7.98336798336e-12                      |
| HP-17B                      | -7.98336798336e-12                      |
| HP-17BII                    | -7.98336798336e-12                      |
| HP-17BII+ mk1               | -7.98336798336e-12                      |
| HP-17BII+ mk2               | -7.98336798336e-12                      |
| HP-19BII                    | -7.98336798336e-12                      |
| HP-20b                      | -7.98336798336e-12                      |
| HP-30b                      | -7.98336798336e-12                      |
| HP-50G                      | -7.98336798336e-12                      |
| HP Prime 2.1.14730          | -7.98336798336e-12                      |
| Casio FC-200                | -8.316008316e-13                        |
| Sharp EL-735                | 0                                       |
| Sharp PC-1403H HPF 188177   | 0                                       |
| Sharp PC-1421               | ERR                                     |
| Victor V12                  | ERR                                     |
| BWK Business                | -0.000019581                            |
| RPN83P v0.9.0               | 0                                       |
| RPN83P v0.12.0 RC2          | 0                                       |
| RPN83P v0.12.0              | 0                                       |
| TI-83 Plus                  | 0                                       |
| TI BA II Plus Professional  | -6.652807e-14                           |
| NSTK TVM V5                 | 4.584636057662297410319999999999998e-10 |
| NSTK TVM V6                 | 0                                       |
| Plus42 1.1.9                | 0                                       |
| C47 1531f1cb2               | ERR                                     |
| C47 eadc4507f               | -3.75935122288958926199999999999999e-19 |
| NSTK TVM V8                 | 0                                       |
| R Rmpfr                     |                                         |
| Ref                         | 0                                       |
| WP43 0.25.2                 | ERR                                     |
| Casio FC-100V               | ERR                                     |
| Casio FC-200V               | ERR                                     |

The Saturns all get the same result, which to me suggests the same algorithm, same starting values and stopping criteria, and same rounding behaviour in each iteration. The HP-12c is very similar which suggests to me it uses the same algorithm with less internal precision.

So if Kinpo were only given specifications for the solver, it must have been very specific! Or they weren't officially given the code, but somehow got hold of it? The HP-12c platinum is not exactly the same as the Saturns though - like the HP-12c it returns the ceiling of N rather than a fraction, and for problem 7 returns a very similar result to the HP-12c.