Mui/mpi

[Dest]

I'm still new to triggering, so what does MUI and MPI means? Rep will be given to one who gives the best answer.

 

[uberfoop]

MUI and MPI describe the 'instanceability' of triggers.

MUI means 'multiple unit instanceable.' It is the highest level of instanceability. With a trigger that is MUI, you can have as many instances running of that triggered sequence as you want at any one time and it will work fine.

MPI means 'multiple player instanceable'. It means that there can be only a specific number (almost always 1) of instances of the triggered sequence running for each player at any one time and it will work fine.

Exceeding the instanceability limit of a certain triggered sequence generally results in bugs involving overwriting variable.

 

[Weep]

You know, when I first came to this site, I was confused by these acronyms too, and had a hard time finding their definition. Maybe a sticky thread is in order?

MUI means 'multiple unit instanceable.' It is the highest level of instanceability. With a trigger that is MUI, you can have as many instances running of that triggered sequence as you want at any one time and it will work fine.

I'd argue that there's yet another level, and I've seen it mentioned on other sites: SUI, or Single/Same Unit Instanceability. MUI just means that at least one instance can be running per unit. What if the same unit casts a spell multiple times before the effect finishes, or the same spell is cast on a target that's already under its effects? If it works, that's SUI.

Some people on The Hive Workshop seemed to think that hashtables in 1.24 would make MUI easy, but would be difficult to use for SUI. (True, to an extent: using a unit as the hash key would mean one instance per unit.)

MUI includes MPI, if not poorly coded.
SUI generally indicates MUI and MPI, but not necessarily (if strangely coded).

The overall principle behind these terms is that a well-coded triggered spell should be able to be cast as often as wanted by as many units as wanted without problem. However, for complex spells, sometimes it's easier to program without the intent to achieve a certain level of multi-instanceability, and for a particular map project (eg. a map where there can only ever be one hero per player), that might be OK.

 

[Dest]

Well, thanks for the replies. I guess both posts give the best answers, so rep to both. =)