When you want to see how J will proceed, you can set up an experiment,
and use echo to show what is happening when.

That said, your "0 verb will operate a box at a time (or a pair of
boxes at a time, since it's dyadic - the "0/ verb thus operating a
pair of boxes at a time but being monadic...).

So... you'll be reading in a pair of files at a time, and accumulating
the results of your myverb in your J session.

I hope this helps,

-- 
Raul


On Fri, Dec 25, 2015 at 4:51 AM, Ryan Eckbo <[email protected]> wrote:
> I'm processing some big files on the order of 2G, extracting >= 250M of data
> from
> each. I have to memory map them to get the data:
>
> readbigfile=: 3 : 0
>   JCHAR map_jmf_ 'f';y
>   NB. get data from f
>   unmap_jmf_'f'
> )
>
> I have about 150 of these files together with matching smaller ones, and I
> need to
> do something like this:
>
> (fread@[ myverb readbigfile@])"0/ SmallFiles,.Bigfiles
>
> My question is how is the J runtime going to execute this: is it going to
> proceed line
> by line or try and read all the big files at once?  If the former, is the
> memory freed
> right after execution? In general I don't know how to deal with huge arrays.
>
> Thanks for any help,
> Ryan
>
>
>
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