manlio_perillo:
Hi.
As with a previous post, I think I have found a possible memory problem with the uvector package.
I have this data structure (for, again, my Netflix Prize project):
IntMap (UArr (Word16 :*: Word8))
I was adding elements to the map using something like:
v = map singletonU (a :*: b)
insertWith appendU k v m
However doing this eats a *lot* of memory.
Today I have rewritten my program to use `alter` and `snocU`:
append Nothing = Just $ singletonU (a :*: b) append (Just u) = Just $ snocU u (a :*: b)
alter append k m
This, finally, works.
Unfortunately I'm still not able to load the entire Netflix Prize training data set, grouping ratings by customers, because my PC has only 2 GB of RAM. The required memory is about 2 GB, but when the system start to swap, I have to kill the program.
So the question is: why appending an array of only one element to an existing array causes memory problems?
It must copy the entire array. -- Don