Why do some PIDs seem impossible to generate?

[SpiffyRegice]

Some PIDs generated by this applet aren't generated by pokesav, those same PIDs cannot be read by IVPID.exe, and when the IV PID combination is fed into legal.exe, it considers the pokemon hacked.

Consider the PID 0454085950, generated by the IVs 20/20/20/20/20/20 with a nature of 0 (hardy).

[Toffeuy]

A pokemon with the IV's 20/20/20/20/20/20 cannot have a hardy nature. The PID 0454085950 is a hardy nature but it doesn't match the IV's so it's considered as hacked.

[SpiffyRegice]

Do you have a reasonable explanation for your assertion? Additionally, why can IVPID.exe not reconstruct the IVs from the PID (option 5 in the program)?

[Toffeuy]

Just use the IV/PID on Pokesav while you have already typed the desired IV's and it will tell you the possible PID's for that IV combination.

[Sabresite]

Cause the applet is wrong.

[damio]

Cause the applet is wrong.

This.

If you really need proof.

http://forum.pokesav.org/viewtopic.php?f=15&t=1076&start=0

Learn.

[SpiffyRegice]

Alright, thanks for the "guide." I'm correcting the algorithms in the program I'm working on (it was based on X-Act's code). Aside from that, why can't IVPID.exe figure out what the IVs are for that PID?

Edited July 20, 2009 by SpiffyRegice

[Jiggy-Ninja]

It's probably an impossible PID.

PIDs are usually generated by 2 consecutive PRNG calls. It's probable that there are some PIDs that are impossible to generate because it is impossible for the PRNG to output the right numbers for it.

I saw the guts of how SCV's PID IV program works. It would use the two halves of the PID to try and reconstruct what seed the PRNG had at the time the Pokemon was made. If it's coming up with no results, that means it can't reconstruct the seed, meaning that the PID is impossible.

I don't know how X-act's works, so I can't speak for that one.

[SpiffyRegice]

That's very interesting, thanks.