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Haskell Space Leak

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问题 all. While trying to solve some programming quiz: https://www.hackerrank.com/challenges/missing-numbers , I came across with space leak. Main function is difference , which implements multi-set difference. I've found out that List ':' and Triples (,,) kept on heaps with -hT option profiling. However, only big lists are difference 's two arguments, and it shrinks as difference keeps on tail recursion. But the memory consumed by lists keeps increasing as program runs. Triples is ephemeral array

Haskell Space Leak

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double stream feed to prevent unneeded memoization?

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问题 I'm new to Haskell and I'm trying to implement Euler's Sieve in stream processing style. When I checked the Haskell Wiki page about prime numbers, I found some mysterious optimization technique for streams. In 3.8 Linear merging of that wiki: primesLME = 2 : ([3,5..] `minus` joinL [[p*p, p*p+2*p..] | p <- primes']) where primes' = 3 : ([5,7..] `minus` joinL [[p*p, p*p+2*p..] | p <- primes']) joinL ((x:xs):t) = x : union xs (joinL t) And it says “ The double primes feed is introduced here to

double stream feed to prevent unneeded memoization?

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How do I parse a large data block into memory in Haskell?

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问题 On reflection, this entire question can be boiled down to something much more concise. I'm looking for a Haskell data structure that looks like a list has O(1) lookup has either O(1) element replacement or O(1) element append (or prepend... I could reverse my index lookups if that were the case). I can always write my later algorithms with one or the other in mind. has very little memory overhead I'm trying to build an image file parser. The file format is your basic 8-bit color ppm file,

Irrefutable pattern does not leak memory in recursion, but why?

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问题 The mapAndSum function in the code block all the way below combines map and sum (never mind that another sum is applied in the main function, it just serves to make the output compact). The map is computed lazily, while the sum is computed using an accumulating parameter. The idea is that the result of map can be consumed without ever having the complete list in memory, and (only) afterwards the sum is available "for free". The main function indicates that we had a problem with irrefutable

How do I parse a large data block into memory in Haskell?

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On reflection, this entire question can be boiled down to something much more concise. I'm looking for a Haskell data structure that looks like a list has O(1) lookup has either O(1) element replacement or O(1) element append (or prepend... I could reverse my index lookups if that were the case). I can always write my later algorithms with one or the other in mind. has very little memory overhead I'm trying to build an image file parser. The file format is your basic 8-bit color ppm file, though I intend to support 16-bit color files and PNG and JPEG files. The existing Netpbm library, despite

Haskell Space Leak

阅读更多关于 Haskell Space Leak

all. While trying to solve some programming quiz: https://www.hackerrank.com/challenges/missing-numbers , I came across with space leak. Main function is difference , which implements multi-set difference. I've found out that List ':' and Triples (,,) kept on heaps with -hT option profiling. However, only big lists are difference 's two arguments, and it shrinks as difference keeps on tail recursion. But the memory consumed by lists keeps increasing as program runs. Triples is ephemeral array structure, used for bookkeeping the count of multiset's each element. But the memory consumed by