Die Suche ergab 12 Treffer

von yc81reja
14. Jul 2017 09:05
Forum: Archiv
Thema: MapReduce Basic Programming Model
Antworten: 3
Zugriffe: 435

Re: MapReduce Basic Programming Model

That's the haskell notation about functions type map takes a lambda that takes parameter of type a returning type b, and takes a list of type a, returns list of type b foldl takes a lambda that takes parameters of type b and a, where the second parameter of type b is "zero" and each of the third par...
von yc81reja
12. Jul 2017 12:03
Forum: Archiv
Thema: MR - Reduce starting time
Antworten: 6
Zugriffe: 443

Re: MR - Reduce starting time

Oh, sorry I think my previous replies are wrong. Now I got what you mean. You are right on your first post. In the paper section 3.1 step 4 it says the reducer has started reading when the output of writers are written on the local disk but until step 5 when the reducers have finished reading and so...
von yc81reja
12. Jul 2017 11:11
Forum: Archiv
Thema: MR - Reduce starting time
Antworten: 6
Zugriffe: 443

Re: MR - Reduce starting time

Well, I would assume that since each worker stores their intermediate values on local storage and reducers are reading them from a mapper, if the mapper is dead after completion, the reducer cannot read the intermediate values from the dead worker because the values are written to its local storage....
von yc81reja
12. Jul 2017 09:54
Forum: Archiv
Thema: MR - Reduce starting time
Antworten: 6
Zugriffe: 443

Re: MR - Reduce starting time

I wouldn't think that the reducers start reading while mappers are still working because the scheduler shuffles the intermediate (key, values) and assigns them to reducers. If reducers start reading before all mappers finish, the partitions they read are incomplete. Please take a look at page 15 of ...
von yc81reja
12. Jul 2017 09:46
Forum: Archiv
Thema: what does RR actually do?
Antworten: 1
Zugriffe: 371

Re: what does RR actually do?

I am not sure if you mean rr. Is that RecordReader? If so, I wouldn't think mapper only does groupByKey(). Please refer to this https://www.quora.com/What-is-the-purpose-of-RecordReader-in-Hadoop And please note the table on page 33 of slide 4 that by reading text file the rr provides (offset, line)...
von yc81reja
5. Sep 2015 19:40
Forum: Archiv
Thema: [Letrec]question regarding recursive let
Antworten: 2
Zugriffe: 350

[Letrec]question regarding recursive let

Hi I have a question on RCFWAE when I turned case letrec codes into case Rec(boundId, namedExpr, boundBody) => { /* val recEnv = collection.mutable.Map() ++ env recEnv += boundId -> interp(namedExpr, recEnv) interp(boundBody, recEnv) */ lazy val recEnv: Env = env + (boundId -> interp(namedExpr, recE...
von yc81reja
1. Sep 2015 12:41
Forum: Archiv
Thema: [Assignment]Solution for assignment 12
Antworten: 1
Zugriffe: 234

[Assignment]Solution for assignment 12

Hello
I'm wondering if the solution to assignment 12 is available
Thanks
von yc81reja
26. Mai 2015 12:02
Forum: Archiv
Thema: Weak references problem
Antworten: 2
Zugriffe: 585

Re: Weak references problem

I've mistaken something in concept of weak reference. Thank you.
von yc81reja
25. Mai 2015 17:27
Forum: Archiv
Thema: Weak references problem
Antworten: 2
Zugriffe: 585

Weak references problem

Hi all, I got one last problem by assignment 7 to implement tryderef. Since I tried some search on google without luck, I personally assume that tryderef will return the interpretation of e if the its weak reference is valid, otherwise interpretation of default will be returned. Correct me about thi...
von yc81reja
21. Apr 2015 11:23
Forum: Archiv
Thema: Some questions regarding scala warm up
Antworten: 6
Zugriffe: 818

Re: Some questions regarding scala warm up

First of all: Please don't post your solutions here, even if they are not completely finished yet! About your questions: Especially the flatten task can be solved very elegantly without any additional functions. Remember that pattern matching is very powerful. In an AE-interpreter, you could for ex...
von yc81reja
21. Apr 2015 09:51
Forum: Archiv
Thema: Some questions regarding scala warm up
Antworten: 6
Zugriffe: 818

Re: Some questions regarding scala warm up

this idea works at me (something modified). I have a function for a recursively addition of 2 lists instead of 3 variables which I described before (now it can be solved with 2 variables and this function for addition of two lists). Hope it can help to solve this task :wink: Thanks for your answer....
von yc81reja
18. Apr 2015 20:10
Forum: Archiv
Thema: Some questions regarding scala warm up
Antworten: 6
Zugriffe: 818

Some questions regarding scala warm up

Hello For entire Saturday I finally finished assignment 1 but I still got some weird warnings, and to be honest, violate the constraints of only using :: operator. So I post my implementation of flatten here: import Util._ object Solution { def flatten[A](xss : List[List[A]]) : List[A] = { def flat[...

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