[erlang-questions] Efficient sum matrix by column

Alexander Petrovsky <>
Sun Apr 12 22:03:03 CEST 2015


I can update only full row every dt second only. Every element in proplist
it's number of requests from client for 1 second smoothed by ewma (i.e.
smoothed rate). Every second I want to recalculate summary rate per client
per cluster (as I say sum by column; sum between all nodes per client).

2015-04-12 22:46 GMT+04:00 Vance Shipley <>:

> On Sun, Apr 12, 2015 at 10:53 PM, Alexander Petrovsky
> <> wrote:
> > I have about 100 nodes in cluster, each node in cluster contains about
> > 100000 elements in proplist. All proplists have equal length, the same
> keys,
> > but different values. I need to get the sum values for every key between
> all
> > proplists. By example, it can be represented as matrix NxM (N~=100,
> > M~=100000), and I need to get the sum by column.
>
> Firstly proplists is probably not the data structure you want to use,
> as has been pointed out.
>
> Secondly you may want to consider storing the column sums, updating
> each time a column row is updated.
> That could be quite cheap to do if the sums are always incremented for
> example.
>
> --
>      -Vance
>



-- 
Петровский Александр / Alexander Petrovsky,

Skype: askjuise
Phone: +7 914 8 820 815
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://erlang.org/pipermail/erlang-questions/attachments/20150413/bd567df3/attachment.html>


More information about the erlang-questions mailing list