Questions tagged [mapreduce]
The mapreduce tag has no usage guidance.
15
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Question about reduction Proof
I've recently seen a proof that the set of Turing machines $L = \{encode(M) |L(M) \text{is closed under reversal}\}$ is not decidable.
The proof used following idea:
Reduce from the $A_{TM}$ problem ...
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0answers
18 views
N-dimensional generalization of map and reduce?
Is there any conceptual generalization of higher-order functions like map and reduce but for N-dimensional objects (e.g. arrays or tensors)?
For mapping, I guess it would be a point-wise ...
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1answer
20 views
Are graphic cards using the Map-Reduce model when performing typical gaming rendering
I know that the Map-Reduce model is a common model of parallel computation, perhaps some sort of standard way(?). I also know that graphic cards are specifically built for parallel computation. ...
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33 views
Why in the Map Reduce Implementation, why not stream the records to the reducer (via TCP) as they are being produced by the mappers?
In the Map-Reduce implementation, the reducers start when all mappers finish their jobs. Why don't we stream the records from mappers to reducers while they are being processed instead? I think there ...
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26 views
Clarification on MapReduce description in textbook
I am reading through chapter 2 of of the free textbook "Mining of Massive Datasets" (http://www.mmds.org/).
On page 28 the following is stated:
"It is reasonable to create one Map task for every ...
1
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1answer
916 views
How does this reduction to prove undecidability account for epsilon?
I have the following proof that the Empty String problem:
ES = {M | M accepts $\epsilon$}
is undecidable:
$f<M,w>$ = Construct a new machine $M_2$ such that:
$M_2$ = given input x erase x ...
-1
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1answer
43 views
Global optimization algorithm based on MapReduce
In the field of the intelligent swarm, there are many algorithms can find global optimization, such as Ant Colony Optimization (ACO), particle swarm optimization (PSO).
Is there any optimization ...
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1answer
38 views
Is there a name for “yield first result parallel map”?
Context
In randomized algorithms two schemes of computation are common:
Las Vegas algorithms with random running time
Randomized algorithms that have a probability of success, and have to be ...
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0answers
33 views
numeric stability of map reduce operations
I am building a small library for computing information retrieval metrics for classifiers (precision, recall, f1, accuracy, whatever). Typically each metric is built by calculating a single value for ...
3
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2answers
2k views
Decidability of Unary Languages / One-to-One Mapping
I'm trying to prove that there exists an undecidable subset of {1}* by showing a one-to-one correspondence between it and {0, 1}* (which would imply a one-to-one correspondence between their power ...
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0answers
40 views
Partitioning millions of items into groups based upon a network of set similarities
So I'm working on a problem at work related to the matching of authors of millions of documents. I currently have minhash sets for each document's syntax (sets of 10 numbers with 8-10 digits each), ...
3
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1answer
700 views
Implement K-means clustering with Map-Reduce
Recently in an interview I was asked to implement k-means clustering using the Map Reduce architecture. I know how to implement a simple k-means clustering algorithm but couldn't wrap my head around ...
2
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1answer
200 views
Can map-reduce speed up the count-min-sketch algorithm?
Is there any possibility of improvement in the result of count-min-sketch algorithm if we will use Map Reduce approach?
Improvement in performance can be in terms of accuracy, time complexity or the ...
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1answer
91 views
Karloff's algorithm applied to sparse graphs
I'm given a graph $G = (V, E)$ with $|V| = N$ and $|E| = m \ge N^{1+c}$ edges for some constant $c >0$. $G$ is called a $c$-dense graph.
Karloff [1, p.6] has given a map-reduce algorithm called "...
6
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1answer
231 views
Are there any non-naive parallel sparse matrix multiplication algorithms?
I was wondering about a problem in analyzing a social network (counting friends-in-common between all pairs of members) that requires squaring its adjacency matrix, and started reading up on ...
