haskell

Memoization in Haskell?

由 懵懂的女人 提交于 2020-07-24 08:45:24
问题 Any pointers on how to solve efficiently the following function in Haskell, for large numbers (n > 108) f(n) = max(n, f(n/2) + f(n/3) + f(n/4)) I've seen examples of memoization in Haskell to solve fibonacci numbers, which involved computing (lazily) all the fibonacci numbers up to the required n. But in this case, for a given n, we only need to compute very few intermediate results. Thanks 回答1: We can do this very efficiently by making a structure that we can index in sub-linear time. But

Memoization in Haskell?

由 China☆狼群 提交于 2020-07-24 08:43:03
问题 Any pointers on how to solve efficiently the following function in Haskell, for large numbers (n > 108) f(n) = max(n, f(n/2) + f(n/3) + f(n/4)) I've seen examples of memoization in Haskell to solve fibonacci numbers, which involved computing (lazily) all the fibonacci numbers up to the required n. But in this case, for a given n, we only need to compute very few intermediate results. Thanks 回答1: We can do this very efficiently by making a structure that we can index in sub-linear time. But

2020年7月中国编程语言排行榜

由 浪尽此生 提交于 2020-07-24 00:35:00
编程语言比例 排名 编程语言 平均工资 中位数 最低 最高 人头 百分比 1 rust 20027 17500 5357 45000 460 0.11% 2 scala 19342 17500 7000 45000 2849 0.68% 3 python 18345 16000 6000 45000 32897 7.80% 4 go 18256 16000 6856 40000 27035 6.41% 5 matlab 18207 17500 7000 37500 5798 1.38% 6 lua 18061 16500 6388 37500 3944 0.94% 7 r 17834 16000 6000 40000 3129 0.74% 8 julia 17667 18929 9000 25000 12 0.00% 9 swift 17053 15000 7000 37500 2770 0.66% 10 perl 16854 15000 5408 37500 2576 0.61% 11 ruby 16196 15000 5250 37500 1373 0.33% 12 kotlin 16106 15000 7000 33050 1217 0.29% 13 haskell 15308 15000 11500 31425 26 0.01% 14 cpp 15282 12500

How do I debug missing variables from SMT-Lib output?

由 放肆的年华 提交于 2020-07-23 06:24:27
问题 Based on this very helpful answer I rewrote my solver-for-a-stateful-program to use the Query monad and an ever-increasing list of SMT variables standing for the inputs. I expected one of two outcomes from this: either the first part (generating the SMTLib output) is sped up a lot and becomes usable, or it still remains so slow that it might as well not work. However, instead I get an error message from the SMT solver (Z3 in my case) complaining about a missing SMT variable in the SMTLib

How do I debug missing variables from SMT-Lib output?

由 夙愿已清 提交于 2020-07-23 06:23:15
问题 Based on this very helpful answer I rewrote my solver-for-a-stateful-program to use the Query monad and an ever-increasing list of SMT variables standing for the inputs. I expected one of two outcomes from this: either the first part (generating the SMTLib output) is sped up a lot and becomes usable, or it still remains so slow that it might as well not work. However, instead I get an error message from the SMT solver (Z3 in my case) complaining about a missing SMT variable in the SMTLib

How do I debug missing variables from SMT-Lib output?

由 会有一股神秘感。 提交于 2020-07-23 06:22:30
问题 Based on this very helpful answer I rewrote my solver-for-a-stateful-program to use the Query monad and an ever-increasing list of SMT variables standing for the inputs. I expected one of two outcomes from this: either the first part (generating the SMTLib output) is sped up a lot and becomes usable, or it still remains so slow that it might as well not work. However, instead I get an error message from the SMT solver (Z3 in my case) complaining about a missing SMT variable in the SMTLib

Is there a way to split an InputStream?

由 送分小仙女□ 提交于 2020-07-23 04:33:37
问题 I wonder if there is a way to "split"/"duplicate" an System.IO.Streams.InputStream from the io-streams package to be forwarded to two processing stages? duplicate :: InputStream a -> IO (InputStream a, InputStream a) I can see that this probably doesn't work with the demand driven nature of streams, but what would be the canonical solution if you need several things to be processed? Would you build a pipeline that "writes to the side"? Like: input >>= countEvents countIORef >>= logEvents

Is there a way to split an InputStream?

由 我的未来我决定 提交于 2020-07-23 04:33:09
问题 I wonder if there is a way to "split"/"duplicate" an System.IO.Streams.InputStream from the io-streams package to be forwarded to two processing stages? duplicate :: InputStream a -> IO (InputStream a, InputStream a) I can see that this probably doesn't work with the demand driven nature of streams, but what would be the canonical solution if you need several things to be processed? Would you build a pipeline that "writes to the side"? Like: input >>= countEvents countIORef >>= logEvents

Is there a way to split an InputStream?

由 本秂侑毒 提交于 2020-07-23 04:31:47
问题 I wonder if there is a way to "split"/"duplicate" an System.IO.Streams.InputStream from the io-streams package to be forwarded to two processing stages? duplicate :: InputStream a -> IO (InputStream a, InputStream a) I can see that this probably doesn't work with the demand driven nature of streams, but what would be the canonical solution if you need several things to be processed? Would you build a pipeline that "writes to the side"? Like: input >>= countEvents countIORef >>= logEvents

Is there a way to split an InputStream?

由 谁说我不能喝 提交于 2020-07-23 04:31:04
问题 I wonder if there is a way to "split"/"duplicate" an System.IO.Streams.InputStream from the io-streams package to be forwarded to two processing stages? duplicate :: InputStream a -> IO (InputStream a, InputStream a) I can see that this probably doesn't work with the demand driven nature of streams, but what would be the canonical solution if you need several things to be processed? Would you build a pipeline that "writes to the side"? Like: input >>= countEvents countIORef >>= logEvents
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