Computer Science Weekly Newsletter

Computer Science newsletter

Top new questions this week:

Automated optimization of 0-1 matrix vector multiplication

Question: Is there established procedure or theory for generating code that efficiently applies a matrix-vector multiplication, when the matrix is dense and filled with only zeros and ones? Ideally, ...

linear-algebra program-optimization  
asked by Nick Alger 11 votes
answered by tranisstor 3 votes

Why is the tape not part of the definition of a Turing Machine?

I've wondered why the tape/tapes are not part of the formal definition of a Turing Machine. Consider, for example, the formal definition of a Turing machine on Wikipedia page. The definition, ...

turing-machines computation-models  
asked by Nicolas Lykke Iversen 5 votes
answered by André Souza Lemos 7 votes

2 Dimensional Subset Sum: looking for information

I do not know if this problems exists with a different name, if it is, I could not find it. The problem is this: Given a set $S$ of $n$ points in $\mathbb{Z}^2$, is there a subset $A\subset S$ ...

np-complete approximation coding-theory  
asked by Harry 4 votes

Equivalence in finite sets of turing machines

I have this exercise and I really don't know how to complete it: Prove that for all finite sets S of Turing Machines it is decidable whether or not given any two Turing Machines M1 and M2 in S they ...

formal-languages turing-machines formal-grammars  
asked by Giulia Frascaria 3 votes
answered by Yuval Filmus 2 votes

Search problem when the effects of actions are not deterministic

The standard search problem studied in AI contains: An initial state $A$; A final (goal) state $Z$; A set of actions that can change the state; each action takes as input a certain state and returns ...

reference-request search-algorithms heuristics  
asked by Erel Segal-Halevi 3 votes
answered by D.W. 1 vote

Minimum edge deletion partitioning of a planar graph

I'm interested in the time complexity of the following problem: Given an undirected planar graph $G=(V,E)$ and a weight function $w:E \rightarrow \mathbb{Z}$ (so weights can be negative, too), color ...

complexity-theory graphs np-hard weighted-graphs  
asked by EmreA 3 votes

Loops at low level

When programming with high level languages like Python or Matlab, it is always better to model the problem such as the solution is some kind of vector or matrix multiplication, to avoid loops. But ...

asked by Mehdi 3 votes
answered by Yuval Filmus 5 votes

Greatest hits from previous weeks:

Difference between Parallel and Concurrent programming?

When looking at concurrent programming, two terms are commonly used i.e. concurrent and parallel. And some programming languages specifically claim support for parallel programming, such as Java. ...

terminology parallel-computing concurrency  
asked by nish1013 11 votes
answered by nish 10 votes

How to fool the "try some test cases" heuristic: Algorithms that appear correct, but are actually incorrect

To try to test whether an algorithm for some problem is correct, the usual starting point is to try running the algorithm by hand on a number of simple test cases -- try it on a few example problem ...

algorithms algorithm-analysis education correctness-proof didactics  
asked by D.W. 52 votes
answered by Per Alexandersson 23 votes

Can you answer these?

State of the art in multi-modal command recognition

I'm currently researching various fusion methods in a multi-modal (video, audio, identity, user position and gesture) human-computer interaction environment (think in terms of a smart-home system). ...

reference-request speech-recognition  
asked by Seanny123 2 votes

How to find an axis-aligned hyper box whose set of integer points minimizes Jaccard distance to a given finite set of points $X \in {\mathbb Z}^d$?

So I saw this question posed on for $d=3$. Suppose we are given a finite set $X \subset {\mathbb Z}^d$ of $n$ points. The goal is to find a hyper box of integer points $ B = [k_{1,1},k_{1,2}] ...

algorithms computational-geometry  
asked by user2566092 1 vote

Help understanding a problem with inclusion/exclusion

I am trying to understand how to use inclusion/exclusion in algorithm. I think I understand the basic example of what the inclusion/exclusion principle is: the principle is in general illustrated ...

asked by testTester 1 vote
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