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Questions tagged [scientific-computing]

Use this tag for questions about using computers in science. Many of these questions also fit on scicomp.stackexchange.com.

Scientific computing encompasses numerical methods, physical simulations, data processing and visualization, and the many other ways in which computers are used to do scientific research.

There is an entire Stack Exchange site devoted to questions about scientific applications of computers. These sorts of questions may get more specialized attention at that site.

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How to realize nested parallel in R on windows platform

I try to use parApply() in parallel package in R. cl <- makeCluster(16) cl.boot <-makeCluster(8) In my programme, I call t(parApply(cl,rv,1,sim.one.test)) first. In function sim.one.test,a call a function boot(). And in boot(), I use …
Sun Dayu
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Retaining an objects attribute in "anonymous" function definition after object is potentially deleted

I'm writing some scientific code in Python which solves a complicated optimization problem and (ideally) returns a list of univariate functions which are a series of solution to the problem at particular points in time (a list of time-indexed,…
CompEcon
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Parallel random number sequence independent of number of threads

There has been a large number of parallel RNG questions here, but I couldn't find one which addresses my variant. I'm writing a function that given a seed fills a long array with random numbers based on that seed. I currently do that serially, but I…
amaurea
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Starter exercises on scientific computing (Python)

I am interested in learning the basics of scientific computing, but sadly in my daily life I don't encounter problems or situations in which I get to code something to solve a mathematical problem (Or any problem whatsoever, other than the basic…
user3013666
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Python: how to evaluate a function on a grid

I'm new to programming and scientific computing. Below is some code for evaluating an exponential integral over a grid. The integral is a function of radial distance from a point. I would like to sum the contribution from multiple points (with…
Cfree
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standard error of the mean function

How do I calculate the standard error of the mean in MS Access? Here is what I have in mind: SELECT Avg(qryAvgGROP.PctGROP_MCAR) AS AvgAvgGROP_MCAR StandardError(qryAvgGROP.PctGROP_MCAR) AS SemAvgGROP_MCAR FROM qryAvgGROP; In this example,…
CodeMed
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Time averaging non-continuous data with PostgreSQL9.2

I have multiple datasets of 1 second time resolution real data. This data will often have gaps in the time-series where the instrument dropped data, or when the instrument was turned off, resulting in a patchy (albeit still very useful) dataset. The…
user3317621
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Database recommendations for hybrid scientific & relational data?

I have a strong use case for mixing up scientific data i.e. double matrices and vectors along with relational data and use this as data source for a distributed computation e.g. MapReduce, hadoop etc. Up to now I have been storing my scientific data…
SkyWalker
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How can I index an unstructured mesh?

I want to import unstructured 2d/3d meshes like this: or this into my simulation. I think unstructured meshes are described with a list of vertices and a list of edges (i.e. which vertices are joined to which other vertices). I don't know how I…
RNs_Ghost
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Options for fast, highly concurrent, in-process access to large datasets

Context: I'm currently leading a project to integrate our application (a model which works with high resolution scientific data - .NET, Winforms) with that of another provider in my company's field (a similar model - .NET, cloud architecture). …
pauld
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Covariance matrix of the variables of a dataset with very small values/

I have a dataset including very small values therefore as you try to compute covariance matrix you conclude NAN values. How should I change the data as I am able to scale those very small values in the computation ? I am using MATLAB but any other…
erogol
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Overwriting data with HDF5 lite

I'm working on a project with HDF5 Lite, and I'm having some trouble writing to an already existing dataset. What I'm currently doing is calling H5LTmake_dataset to accomplish this, but this causes an error. Currently, the error I'm getting is from…
Andrewziac
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How can one perform high precision convolution in Python?

I am doing convolution operations involving some very small numbers, and am encountering a lot of underflow on the way.
user2354033
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MATLAB's griddata3 for NumPy?

I realize that there is a griddata for NumPy via Matplotlib, but is there a griddata3 (same has griddata, but for higher dimensions)? In other words, I have (x,y,z,d(x,y,z)) where (x,y,z) form an irregular grid and d(x,y,z) is a scalar function of…
reckoner
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Which has more functions for Signal and Image Processing - Matlab or Python?

Which has more functions for Signal and Image Processing - Matlab or Python? I am not concerned with efficiency, only with their comprehensiveness in terms of functionality they offer to the programmer. My field is biomedical research. I process…
user2654449
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