Tag Archives: computing

Searching for Nearest-Neighbors between Two Coordinate Catalogs

Say I have two catalogs of points, each in two-dimensional space. For each object in a catalog, I want to find the nearest object(s) in the other catalog. I can do this by computing the distances between every single unique … Continue reading

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g3data

This is all I needed to use this: Love Debian.

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SciPy Weave Bug in Debian Squeeze

I was trying to remove a bottleneck by converting a portion of Python code into C++ via scipy.weave.inline, and encountered a bug. Here is my code: And this is what I get: Fortunately there is a fix: The fix for … Continue reading

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Comparing the Efficiencies of Gaussian Convolution Routines

These days I quite often need to convolve (i.e., smooth) 2D images by some Gaussian. There are quite a few routines that can do this with varying efficiencies. So I compared a couple of them. On my laptop, this script … Continue reading

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FFTW on Debian Squeeze (AMD64)

Installing from Debian Repository $ sudo aptitude install libfftw3-3 libfftw3-dev The second package is only necessary for development. Installing from Source The version of FFTW I use here is 3.2.2.  Follow this: $ mkdir tmp $ cd tmp $ wget … Continue reading

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ATLAS on Debian Squeeze (AMD64)

Installing from Debian Repository $ sudo aptitude install libatlas3gf-base $ sudo aptitude install libatlas-base-dev The second line is necessary only for development. Installing from Source Disable CPU throttling.  Find out how many CPUs I have: $ cat /proc/cpuinfo … info … Continue reading

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Installing mpi4py on Debian Squeeze

I want to do parallel computing on my desktop to take advantage of quad core.  Actually, I just need to test programs to be run on HPC clusters.  It is actually easy to set up a parallel computing environment. Install … Continue reading

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Installing Sage (Math Library) on Debian Squeeze

First, download the source to some directory (here /usr/local/sage) from one of the official repositories (here it’s at U. of Washington, just for an illustration).  Move to the directory and then $ wget -c http://boxen.math.washington.edu/sage/src/sage-4.6.tar $ sudo aptitude install gcc … Continue reading

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Installing GFortran on Mac OS X Snow Leopard

Installing from GFortran Wiki (My Current Preferred Way) GCC Wiki has a link to Mac OS X installer.  As the command gfortran will be installed at /usr/local/gfortran and causes less interferences with other libraries and software, this is my preferred … Continue reading

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Installing ATLAS on Mac OS X Snow Leopard

Installing from Fink Do: $ fink install atlas atlas-shlibs That’s it.  They will be installed under /sw/lib. Installing from Source (Recommended if Building Other Software That Depends on ATLAS) First of all, I need a FORTRAN compiler, so install it.  … Continue reading

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