how does gamepress calculate the best moveset?

Charge moves DPS isn't accurate. Weave DPS is way more accurate.

DPS = Damage/Second

Weave = {[QuickMoveDamage * round(QuickMoveEnergy / 100)] + (ChargedMoveDamage * ChargedMoveBars)} / {[QuickMoveCooldown * round(QuickMoveEnergy / 100)] + [ChargedMoveBars * (0.5 + ChargedMoveCooldown]}

Not exactly the most accurate, since this doesn't account energy gained from taking damage and dodges. Also, holding on the screen may not take full 0.5 seconds, it might be more or less, depends on your reaction time and phone lags.

Some opinions from previous discussions. Seems that GP, simulations and personal preferences don't always agree.

https://pokemongo.gamepress.gg/q-a/vote-zapdos-or-raiku#comment-574956

https://pokemongo.gamepress.gg/q-a/zapdos-moveset

Edit: How do I make hyperlinks?

Weave damage was already mentioned and is the correct answer. You will see the full effect of energy generation from attacks and taking damage when you look at sims.

I think gamepress should just remove the True DPS mention from charge moves since it doesn't give any relevant information and only misleads and confuses people. Weave DPS increase over just doing the pokemon's fast attacks would be a more relevant metric for example.

Gamepress doesnt calculate it. Its more like deciding overall usage of a pokemon at current meta.

Looking at DPS for charge moves by themselves is flawed. DPS is a terrible measurement for charge moves. Take Machamp as an example, it has Dynamic Punch which is considered as one of the very best charge moves in game right now, and Close Combat which if you only look at DPS it's among top 3 of all charge moves in game.

With a full charge bar, you can cast Dynamic Punch twice (only 50 energy required to cast one), for 180 power over 5.4 seconds.

One Close Combat is 100 power over 2.3 seconds. In that extra time leftover, casting three Counters brings it to a total of 136 power over 5.0 seconds, or a fourth for 148 power over 5.9 seconds.

So Counter/Dynamic Punch does more damage than Counter/Close Combat, despite Close Combat has higher DPS than Dynamic Punch.