The computing tag has no wiki summary.
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88 views
N-grams or vector space model for text mining?
I have a database that contains 5 columns that contain 0 or 1 base on true or false. Each user can choose 4 out of 5 columns which means we can have a max 5 number of 1 and then last will be 0. The ...
2
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2answers
79 views
Anomaly Detection in a set of points
I have a set of points in a matrix of size 100 x 100(total 10000 points). I know that there are roughly 500 anomaly points in it. There is a corresponding truth file which contains the true anomalous ...
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0answers
48 views
Entropy of counting Bloom filter
I'm trying to find the entropy of the counter of a counting Bloom filter but I haven't been able to do it. I know that the probability that the $i^{th}$ counter is incremented $j$ times is:
$$
...
2
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1answer
83 views
Avoiding matrix inversions with the multivariate Gaussian distribution?
Let $(X, Y)$ be a Gaussian random vector with mean $\mu$, variance $\Sigma$ and both $X$ and $Y$ are vectors. No structure is assumed on $\Sigma$ (aside from being symmetric positive definite).
Is ...
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1answer
136 views
How important is using the exact method for ties in a Cox model, and how long should this take?
I'm analyzing the results of some simulation work using a Cox proportional hazard model, and I have what I perceive are a great many ties in the data, representing when a particular individual in the ...
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1answer
80 views
Inverse of the central difference operator
The central difference is a method to approximate numerically the derivative of a function sampled at discrete intervals. In R, one would do:
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2
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3answers
441 views
Command-line tool to calculate basic statistics for stream of values
Is there any command-line tool that accepts the flow of numbers (in ascii format) from standard input and gives the basic descriptive statistics for this flow, such as min, max, average, median, RMS, ...
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0answers
226 views
Computing the expected value using the sample mean gives poor convergence?
This is for Project Euler problem #371:
http://projecteuler.net/problem=371
My solution was to generate a huge random pool of numbers between 0 and 999 inclusive, repeatedly ask the question 'How ...
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6answers
1k views
Computation speed in R?
I have been tasked with moving one of our current large stochastic models out of SAS and into a new language. Personally, I prefer a traditional compiled language, but the PI wants me to check out R, ...
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5answers
4k views
How to sample from a normal distribution with known mean and variance using a conventional programming language?
I've never had a course in statistics, so I hope I'm asking in the right place here.
Suppose I have only two data describing a normal distribution: the mean $\mu$ and variance $\sigma^2$. I want to ...
1
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1answer
115 views
Is there a qualitatively useful statistic or approach to an ill-behaving sample average?
I was running some timing simulations on a computer. As is often done with low latency things like this, I was running the relevant block in a loop $k$ times and then recording the total time over $k$ ...
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2answers
405 views
How to make R's gamm work faster?
Last night I started a complex calculation with gamm() and it took me...
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1answer
134 views
Multiple simulations of a system under different conditions - paired data?
I am currently generating data by simulating a model of chemical system under different conditions (temperature) over time. In each simulation, the starting structure being modeled is exactly the same ...
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0answers
104 views
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0answers
218 views
How to compute the weight matrix for WLS estimation of a multi-group ordinal CFA model
I am attempting to perform a two-group confirmatory factor analysis (CFA) of one continuous factor on six ordinal predictors in OpenMx (...
7
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1answer
215 views
Symbolic computer algebra for statistics
What functionality should exist in a CAS that was specifically geared toward Statistics?
Symbolic algebra systems like Mathematica and Maple are often used for calculus, logic, and physics problems ...
10
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4answers
202 views
Testing statistical software
What techniques/approaches are useful in testing statistical software? I'm particularly interested in programs that do parametric estimation using maximum likelihood.
Comparing results to those from ...
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4answers
3k views
C++ libraries for statistical computing
I've got a particular MCMC algorithm which I would like to port to C/C++. Much of the expensive computation is in C already via Cython, but I want to have the whole sampler written in a compiled ...
3
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0answers
386 views
Computing platform for R: System76 Linux laptop with dual core i5 or quad core i7?
Even though this is not directly a question related to statistical analyses, I thought this group might have some useful insights. My school windows-xp based workstation takes several hours to run ...
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1answer
215 views
Online, scalable statistical methods
This was inspired by Efficient online linear regression, which I found very interesting. Are there any texts or resources devoted to large-scale statistical computing, by which computing with ...
3
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1answer
264 views
Which method to use for anomaly detection?
I think people here could guide me in solving a problem related to anomaly detection in Computer Science. The term anomaly here refers to some undesired event occuring in the system like a virus ...
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4answers
2k views
Who uses R with multicore, SNOW or CUDA package for resource intense computing?
Who of you in this forum uses ">R with the multicore, snow packages, or CUDA, so for advanced calculations that need more power than a workstation CPU? On which hardware do you compute these scripts? ...
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3answers
237 views
Visualization of a multivariate function
This is somewhat vague, but suppose you have a black box function $f(x_1,x_2,\ldots,x_k)$, for which you have code, and you are interested in the behaviour of $f$ when the $x_i$ are i.i.d. standard ...
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9answers
974 views
What books provide an overview of computational statistics as it applies to computer science?
As a software engineer, I'm interested in topics such as statistical algorithms, data mining, machine learning, Bayesian networks, classification algorithms, neural networks, Markov chains, Monte ...
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2answers
763 views
How to get around Numerical Overflow in Stata?
I am working with a large data set (approximately 50K observations) and trying to running a Maximum likelihood estimation on 5 unknowns in Stata.
I encountered an error message of "Numerical ...
