[Haskell-cafe] Is there a library that has a strict version of `sum`?

Damian Nadales damian.nadales at gmail.com
Tue Aug 14 18:57:12 UTC 2018


On Tue, Aug 14, 2018 at 8:10 PM Vanessa McHale <vanessa.mchale at iohk.io>
wrote:

> Yes, that was what I was never quite clear on. What is your *actual
> problem, in context*, not the problem you think you have because you read
> elsewhere that foldl' is more efficient?
>
> The problem I have is that sum consumes huge amount of memory. In
particular I'm modeling the Chimeric ledgers described in this paper
https://eprint.iacr.org/2018/262.pdf. In several places I have to sum up
values in different lists, and as soon as I try this with large lists the
memory usage blows up. So that's my concrete scenario.

In view of this, I though, "I can write this replacing `sum` by `foldl' (+)
0` but wouldn't be nice if this function was defined already somewhere
else?" That's it.

Please ignore this if it is a silly question, and my apologies in advance.


> On 08/14/2018 01:07 PM, Bryan Richter wrote:
>
> On 08/14/2018 11:22 AM, Damian Nadales wrote:
>
>
> Ok, so if understood the bottom line of the answers I got from
> Vanessa and Hiromi the take away seems to be: if you're prototyping
> then stick to the lazy version of sum, otherwise use more advanced
> data structures (Vectors or Folds).
>
> Are you implying that lazy functions are only good for prototyping? Or
> is there something wrong with sum in particular?
>
> More generally, why isn't sum working for you?
>
>
>
>
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