# All Questions

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### Is there exist an external radix sort algorithm?

Is a version of radix sort that can work in list that do not fix in memory? Or other linear time sorting algorithm that can work in that way?
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### Data Compression Algorithm for Less repetitive pattern (redundancy) [on hold]

Context: Lossless Data compression (source coding) algorithms heavily rely on repetitive pattern (redundancy) Questions Which data compression method/algorithm deals with less repetitive ...
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### Why Transmission depends on the Interference of other Links

I was reading Congestion aware channel allocation with route scheduling in wireless cognitive radio mesh network, (by Jia et el, Computers and Electrical Engineering 39 (2013) 1346–1357) and I found- ...
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### Using Data Compression on the output of Data Compression

Context: Lossless Data compression (source coding) algorithms heavily rely on repetitive pattern (redundancy) Questions Is there a data compression method/algorithm that uses another data ...
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### Computational Complexity of Exponential Expression Divisibility?

Garey and Johnson mentions the problem of 'Exponential Expression Divisibility" as "Not known to be in NP or co-NP, but solvable in pseudo-polynomial time using standard GCD Algorithms". Pseudo-...
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### Minimal hypergraph transversals

the exact complexity for hypergraph transversal problem is yet unknown and is an open research problem. However, I would need a fast way to compute, on paper, the minimal transversal of a hypergraph. ...
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### Overflow of integer counter in distributed systems

I've just been introduced to Paxos. There is notion of the of value that is incremented each time a new proposal is send. To provide order for proposals, something like time. What happens when this ...
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### how to computer-scientifically remove virus on my laptop [on hold]

My laptop got some virus. The model is ASUS VivoBook E200HA-US01-GD. The problem is, I don't trust these antivirus softwares. Is there a way to remove virus using computer science?
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### ImageCreate() php in ubuntu [duplicate]

i've got an error in ubuntu.Can you guys help me?plzzz :( imagepng(Image_QRCODE_H.png): failed to open stream: Permission denied in /var/www/html/qrcode/phpqrcode/qrimage.php on line 43
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### ImageCreate() php in ubuntu [on hold]

i've got an error in ubuntu.Can you guys help me?plzzz :( imagepng(Image_QRCODE_H.png): failed to open stream: Permission denied in /var/www/html/qrcode/phpqrcode/qrimage.php on line 43
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### Complexity of matrix inverse via Gaussian elimination

I'm trying to determine the exact complexity of finding an $n\times n$ matrix inverse of $A$. If it is known that the complexity of Gaussian elimination is $\frac{2}{3}n^3 + \frac{1}{2}n^2+O(n)$, then ...
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### Input/Output encoding using LSTM for time series prediction

I have a rather basic problem with understanding LSTM neural networks. My basic problem is predicting a timeseries of data points. Each time step gives me a single value which can be encoded as a ...
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### Solving systems of boolean equations

So I have a system of equations where varibles range over $\{0,1\}$ and the only operation is logical or ($\lor$). Each equation is of the one of two forms 1) $a = b \lor c$ 2) $1 = a \lor b$ where ...
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### Fast generalised suffix array construction: lower than O(n^2 log n)

There is a lot in the literature about linear time constructions for suffix arrays; DC3, radixSA46, and more... However, these, I believe, are only for suffix arrays; with a single string input. Are ...
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### Is there a philosophical counterpart question to P != NP?

Gödels motivation to prove his incompleteness theorems was the philosophical statement "This sentence is wrong.". Is there a philosophical counterpart to the statement P != NP? For example such ...
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### how to uninstall windows 10 on my mac? [on hold]

I clicked a windows 10 ad link on my macbook then it just wiped my drive and put a windows 10 on it. I think the ad link is a spam, now my mac runs windows 10 instead of mac os. How to fix this?
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### How does first instruction get executed in virtual memory environment?

Currently I'm reading about virtual memory , Now I'm stuck at how CPU generate first virtual address for a process ? how page table is formed ? How this setup had been made?
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### Why do we use expectation in reinforcement learning? [migrated]

In reinforcement learning we use lot of expectations, what's the logic behind them? Like in reward function, we use expected return instead of return, in value functions V and action-value functions ...
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### Why not space out memory allocations?

In ext4 file system, the files are spaced out as far apart as reasonably possible to allow for efficient reallocation. Why do we not do this in memory? Why not allocate one memory as page 20, and the ...
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### Identification and the definition of data type

A frequently cited definition of data type is that it is a set of values and a set of operations of those values. I've never read any mention along the lines of a type must be capable of being ...
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### SSA Phi to Registers

I'm working on an LLVM-like kit for .Net - because this is something that's lacking in .Net and I really want to learn the more advanced compilation theory. I'm really struggling to find anything ...
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### Understanding N process Peterson's algorithm

The intuitive informal description of two process Peterson's algorithm for process 0 can be given as follows: ...
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### Preparing precedence graph from fork and join code

I was referring to this page which defines fork, join and precedence graph as follows: When the statement ...
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### Why is first-order logic (without arithmetic) VALIDITY only recursively enumerable, and not recursive?

Papadimitriou's "Computational Complexity" states that VALIDITY, the problem of deciding whether a first-order logic (without arithmetic) formula is valid, is recursively enumerable. This follows from ...
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### Clustering with probabilities / vector quantization with arbitrary distance measures

Suppose I'm given $n$ points $x_1,\dots,x_n$ in some space $\mathcal{S}$ (think: $\mathbb{R}^d$), and probabilities $p_1,\dots,p_n$ that form a probability distribution (so $p_1 + \dots + p_n=1$). ...
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### What is the complexity of Array[n] and Object.value

I faced a great doubt about the Complexity of two ways of calling a information. First I have an Array, if I call an array in a program like this: print array[0] ...
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### AC-3 Algorithms on CSP problem, What is happened when enocunter to an empty domain variable?

Suppose We Applying Arc-Consistency (AC3) algorithms on one Constraint Satisfaction Problem, if domain of one variable be empty, what is the next step of this algorithm? According to This Link and ...
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### How can I find the “thinner” path from a cloud of coordinates? [migrated]

Following up with this, I have a bunch of coordinates and I draw them on a bitmap image as a coordinate system. Now, I would like to get rid of all the noise, and filter coordinates to give a "clearer"...
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### Typed representation of a memory model

Assume a simple procedural language, where statements write and read from local memory via references and procedures accept arguments of n different scalar types (say floats, ints and strings) and ...
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### Clarification on the inapproximability of set cover

I'm trying to understand the inapproximability of the minimum set cover problem. The wikipedia page states that it is hard to approximate within a factor of $(1-o(1))\ln n$ and that $n$ refers to the ...
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### Linear equation in n variables with non negative solution [migrated]

The problem is that given a positive integer y and n positive integers x1 , x2 , ... , xn does there exist non negative integers ...
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### When a trained RNN is tested, is the number of time-steps same for every input?

I am a beginner in deep learning so bear with me. If I want to unfold the RNN in order to represent the relation of output to the input as a non-recursive functions I would have to know the number of ...