Quick HP42S question

[Valentin Albillo]

(05-24-2020 11:37 PM)Thomas Okken Wrote:  The RECT and POLAR commands from the MODES menu are programmable.

Thank you very much, ijabbot and Thomas. I had located both functions in the catalog but mistook them for rectangular/polar conversions

By the way, Thomas, a question regarding Free42/BCD for Android (though I think it will be the same for other operating systems).

I've programmed the exact same algorithm for both Free42 and the HP-71B. The algorithm generates and uses many thousand random numbers, initialized with 1, SEED in Free42 and RANDOMIZE 1 in the HP-71B.

As I thought Free42 includes the exact same RNG that a physical HP42S uses (which was taken from the HP-71B), I expected both programs to give the same results, but upon running them I discovered that in fact they don't. Both sequences of random numbers stay the same for a while but after some time they begin to not be exactly alike and when the programs use them they give slightly different results, perhaps 2147 and 2148, respectively.

The question is: is the RNG in Free42 guaranteed to produce the exact same sequence of random numbers as a physical HP42S would, no matter how long, or will they eventually part ways ?

If the RNG in Free42 is actually different, how many random numbers will it provide before repeating ? I know the one in the HP-71B and so the HP42S will produce 1,000,000,000,000 random values before repeating, and the sequence passes the Spectral Test. Is this also the case for the one in Free42 or does it have a longer period ?

Thanks and best regards.
V.