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Battle Dome

The Battle Dome is one of seven facilities located in the Battle Frontier, accessible only in Emerald. The Frontier Brain here is Tucker.

Modes

The Battle Dome has options for Single Battles and Double Battles.

The player can enter three Pokémon in Singles and three in Doubles.

Mechanics

Gimmick

During each battle, each Trainer can only bring two of their three Pokémon to the battle. Before each battle, the player will be shown an info card on the enemy Trainer (including the three Pokémon they are using), which can reveal some information about potential moveset & stat distributions, allowing the player to choose their team accordingly.

Battles are additionally set up in a 16-player tournament-style bracket, and the player must win the entire bracket to finish a round in this facility. Trainers are seeded based on their Pokémon's stats. The Frontier Brain will always be the Trainer that the player fights in the finals of the tournament, when the player has defeated enough tournaments to cause him to be an opponent in the bracket.

General

Mechanics that apply to every Facility are on the Battle Frontier page. Here are mechanics specific to the Battle Dome:

• Two Pokémon of the same species, or with the same held item, cannot be entered. Opposing Trainers will never use two Pokémon of the same species, or with the same held item.
• Items cannot be used during battle.
• The player's Pokémon will be automatically healed after every battle.
• Items used or swapped (via Trick, Thief, Covet, or Knock Off) during the battle will be given back to the Pokémon after the battle.

Resources

• This post has a lot of general information, including AI quirks and opposing Pokémon's speed stats for both Level 50 and Open Level modes, though keep in mind the speed stats will be inaccurate for Dome due to the 3IV bug discussed below.
• Dome Assistant by Mow
• Speed tiers for Level 50 opponents, taking into account the 3IV bug, and additional implications of that bug

Frontier Brain

The Frontier Brain, Tucker, appears first in the fifth tournament and again in the tenth. After defeating him the second time, he will appear every five tournaments with his Gold Symbol team. His Pokémon have 20 IVs in his Silver Symbol battle and 31 in his Gold Symbol battle. The gender and Ability of his Pokémon are random. His teams are as follows:

Silver Symbol

Tucker Battle (1st)

Pokémon		Nature	Item	Moves								HP EV	Atk EV	Def EV	SpA EV	SpD EV	Spe EV
	Swampert	Brave	Focus Band	Surf		Earthquake		Ice Beam		Counter		152	152	106	100	0	0
	Salamence	Adamant	Lum Berry	Earthquake		Brick Break		Dragon Claw		Aerial Ace		152	152	106	0	0	100
	Charizard	Quiet	White Herb	Overheat		Rock Slide		Aerial Ace		Earthquake		100	152	106	0	0	152

Gold Symbol

Tucker Battle (2nd)

Pokémon		Nature	Item	Moves								HP EV	Atk EV	Def EV	SpA EV	SpD EV	Spe EV
	Swampert	Brave	Leftovers	Surf		Earthquake		Ice Beam		Mirror Coat		252	252	6	0	0	0
	Metagross	Brave	Quick Claw	Psychic		Meteor Mash		Earthquake		Protect		252	252	6	0	0	0
	Latias	Modest	Chesto Berry	Thunderbolt		Psychic		Calm Mind		Rest		252	0	252	0	0	6

Trainers and Pokémon

The list of Trainers that can be encountered is located here. The list of Pokémon that can be encountered is located here.

In other facilities, the Trainers that can be generated for a given round of 7 battles are dependent on which round of 7 the player is facing. In the Battle Dome, a round of 7 battles is functionally equivalent to a single tournament.

When generating Trainers for the tournament, the game will select 10 Trainers from the current round's tier, and 5 from the next round's tier. All Trainers are then seeded after being generated. If the Frontier Brain, Tucker, is set to appear in a tournament, he will replace either the 1st or 2nd seed Trainer, whichever allows him to be on the opposing side of the tournament bracket from the player.

Note that, due to a bug, all Trainers except for Tucker will have 3 IVs instead of whatever is listed on the Trainers page.

Battle Points

The player will receive 1 Point for winning the first tournament, 1 for the second, 2 for the third, 2 for the fourth, etc. to a maximum of 15 Points per tournament. An additional 10 Points are added every time the player faces and defeats Tucker.

Seeding

Before the tournament begins, the game first orders all Trainers (including the player) from strongest to weakest, and then decides which Trainer will face which other Trainer based on this. The process is common to real-world tournament bracketing and is called 'seeding'.

The left side of the bracket features matches between the following seeds: 1 vs 9, 13 vs 5, 8 vs 16, and 12 vs 4. The right side features matches between 3 vs 11, 15 vs 7, 6 vs 14, and 10 vs 2. This differs from most real-world brackets, where the highest seed faces the lowest seed, then the next highest and next lowest, etc.

The game calculates the seed for each trainer as follows:

1. First, calculate the stats of every Pokémon. For the player, the game will use the actual stats that the player will see when navigating to the Pokémon's stat screen. For opposing Trainers, EVs are ignored due to a bug. The level used to calculate opposing Trainers' Pokémon is set to level 50 if the challenge is level 50, and the player's highest-level Pokémon if the challenge is open level (though there is a glitch here; see below).
2. Add up all of the calculated stats. I'll call this sum 'S' in the next steps.
3. Calculate the number of unique types represented on each team. For example, a team of Swampert, Pelipper, and Camerupt would have 4 unique types (Water, Ground, Flying, and Fire). Multiply this sum by the level of the challenge (level 50 for a level 50 challenge, and the level of the highest-leveled Pokémon in the player's team for open level). I'll call this product 'P'.
4. Divide P by 20. If the result is not an integer, round it down to an integer. I'll call this quotient 'Q'.
5. Add S to Q to get the final value.

This value can also be represented with the formula: stats + floor((# unique types * level) / 20).

The highest value receives seed 1, the second highest receives 2, etc. In the case of a tie, the Trainer whose index number (shown here) is lower will receive the higher (better) seed. The Frontier Brain, Tucker, will always be either seed 1 or seed 2, whichever allows him to be on the opposite side of the bracket as the player (so that he can fight the player during the finals).

There are three bugs that affect this calculation, however:

1. Twice, the formula uses the value of the level of the challenge: once when calculating the opponent's Pokémon's stats, and again when multiplying it by the number of unique types. In the open level mode, the game will use the highest-level Pokémon in the player's party to complete this calculation. However, due to a bug, it looks at the player's entire party, not just the Pokémon they enter into the tournament. Therefore, if the player has three level 60 Pokémon and one level 100 Pokémon, the game will run the seeding calculations assuming level 100, even if the player enters the three level 60 Pokémon.
2. In the 'Trainers and Pokémon' section above, I mentioned that all Trainers have 3 IVs. The calculation for seeding uses the Trainer's correct IVs, instead of 3.
3. Any Pokémon used by an opposing Trainer that has a stat over 255 (except for HP) will have that stat calculated as the remainder when the stat is divided by 256 ("stat value mod 256"). For example, a stat of 281 has a remainder of 25 when divided by 256, so a stat of 281 will be treated as 25 when adding up the Pokémon's stats (281 mod 256 = 25). A stat of 249 will be unaffected. In Level 50, this affects only Shuckle, but in Open Level, more Pokémon will be affected the higher the levels are. This means that some Trainers with high stats will actually be seeded much lower than they should be, as the game thinks they have lower stats. This doesn't affect the player.

Opposing Trainer Description

When the player goes to fight an opposing Trainer, they are given a small info card for the Trainer that shows their three Pokémon, and three lines of information. The first line references the Trainer's potential to win the tournament, as determined by the Trainer's seeding. The second line gives information about the moves their Pokémon know, and the third gives information about their Pokémon's stat distribution.

Potential

A Trainer's potential line is determined by their seed, discussed above. The following texts are used for each seed. Tucker has a unique text.

Moves

Almost every move in the game is assigned one or more traits. When deciding what to show for an opposing Trainer's move style, the game will calculate how many moves of each trait the Trainer has, and then scroll through a list of potential descriptions until it finds the first match. Move traits are shown in the table below.

The move styles are shown in the table below.

Stats

The third line of the info card shows which stats the Trainer emphasizes or neglects, if any. To calculate what text to display, the game will first determine the total EVs that the team has in every stat. In the case where a Pokémon has a nature that boosts or hinders a stat, that stat's EV for that Pokémon will be increased or decreased by 10%, respectively.

Once this calculation is complete, if any one stat comprises 30% or more of the team's total EV distribution, the game will choose to display text indicating that the Trainer emphasizes that stat. If no stats account for 30% or more of the total EV distribution, the game will instead take any stat that accounts for 0% of the distribution and display text indicating that the Trainer neglects that stat.

If two stats are emphasized or neglected, the game will display both. If three or more are emphasized or neglected, the game will display only two stats, selecting them in this order: Special Defense, Special Attack, Speed, Defense, Attack, and HP.

If no stat is emphasized or neglected, the game will say the trainer "[r]aises Pokémon in a well-balanced way".

Opposing Trainer Pokémon Selection

The game applies some calculations to determine which two Pokémon it thinks are best suited to take on your team of three. The basic gist of it is that the game will check all three of its Pokémon's moves against your Pokémon, calculate a score for each Pokémon, and have the Trainer select the two Pokémon with the highest scores.

The score for each opposing Pokémon is calculated as follows:

1. Set the Pokémon's score to 0. Then, begin to check each of its moves against each of your Pokémon.
2. If the move has a power of 0, ignore it and skip to the next move.
3. If the move is Ground-type and your Pokémon has Levitate, set the effectiveness of the move to 1. (This is identical to the effectiveness value of a move hitting neutrally, which must be a bug since that's not how Levitate and Ground moves actually interact.)
4. If your Pokémon has Wonder Guard, set the effectiveness of the move to 1. (Again, a bug, and it will never properly recognize super-effective moves because of this either.)
5. Otherwise, set the effectiveness based on how the move hits your Pokémon. A move you're immune to (based on type, not ability) is 0; a move that's doubly not very effective is 0.25; a move that's not very effective is 0.5; a neutral move is 1, a super effective move is 2, and a doubly super effective move is 4.

Note that the only abilities checked during this sequence are Levitate and Wonder Guard. Therefore, using an Electric move on a Volt Absorb Pokémon gives an effectiveness of 0.5 (as Electric resists Electric), instead of 0 (because Volt Absorb users don't take damage from Electric moves). The same applies to any other immunities conferred by ability.

Once the effectiveness of each move is determined, convert that into a score. Every Trainer will randomly be assigned a style: offensive or defensive. Which style the Trainer has determines how each effectiveness value is converted to a score; see the below table. The top row's values are the effectiveness values, and the bottom rows show how many points each move will get for having that effectiveness in that style.

Yes, this means that a Trainer with a defensive style will actually prefer Pokémon whose moves are resisted by, or ineffective on, your Pokémon.

After calculating each Pokémon's score (as a sum of all its scores against your individual Pokémon), the game will then check for ties.

• If the Trainer's chosen style results in a three-way tie, but the other style does not, the game will switch the Trainer to using the other style.
• If both styles have a three-way tie, the game will keep using the original style for the Trainer, and select two Pokémon randomly.
• If two Pokémon tie, and both have the lower score, the game will choose the Pokémon with the highest score, and then randomly select one of the two tied Pokémon.
• If two Pokémon tie, and both have the higher score, the game will choose both Pokémon.
• If no Pokémon tie, the game will choose the two Pokémon with the highest scores.

After choosing the two Pokémon, the game will then determine which order to send them out in. Tucker will always send his Pokémon out in the order that they're listed for his team. Other trainers have a 60% chance to send them out in the order they're listed, and a 40% chance to send them out in the reverse order.

There is a bug with this process that can affect the scoring. The way that the code is set up, it seems as though it's supposed to be the case that the game checks the opposing Trainer's scores against all three of your Pokémon. However, in reality, the scoring is only calculated after you have already selected two Pokémon to bring to the match. The result is that the game scores against those two Pokémon, plus a third 'default' Pokémon that you don't actually have. This 'default' Pokémon is always treated as a Normal-type, which means that Pokémon with Fighting-type and Ghost-type moves might have skewed scoring. It also means that the game doesn't calculate scoring against the third Pokémon in your party, which can affect which Pokémon the enemy Trainer will choose to bring. The Dome Assistant listed above will give you information about which team the enemy Trainer may bring depending on which of your two Pokémon you choose to enter, allowing for you to make decisions that take this bug into account.

AI vs. AI Battles

For battles between two AI Trainers, the game will assign each Trainer a score based on a calculation that takes into account the number of super-effective moves against the opposing team, the base stat total of each Pokémon, the Trainer's seed, and a random value. The Trainer with the highest score will advance to the next round. If there is a tie, the Trainer with the higher seed advances.

Due to a bug, these scores are not reset between simulations. Therefore, if a simulation between Trainers A and B ends with Trainer A having 10 points and B having 20 points, when the game simulates a battle between Trainers C and D, Trainer C will start with 10 points and Trainer D will start with 20. This means that it's not really useful to know how the calculation works in great detail, since only the first battle will work as intended.

What is useful is that the game may display the move that a Trainer used to win a round. The player may be able to use the listed move to eliminate potential enemy movesets from the possible sets.