Tag Archives: research

Searching for Nearest-Neighbors between Two Coordinate Catalogs

Posted on June 28, 2012 by Taro

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

Posted on May 11, 2011 by Taro

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

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Half-Light Radii for Various Profiles

Posted on February 14, 2011 by Taro

For a radial profile of , the enclosed flux within the radius is given by I’m only concerned about azimuthal symmetric cases, so .  The idea is to solve for . Gaussian Profile Say the Gaussian intensity profile is given … Continue reading →

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SciPy Weave Bug in Debian Squeeze

Posted on February 4, 2011 by Taro

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: running build_ext running build_src build_src building extension “sc_1eb4d019edb4774720031f15557074a811″ … Continue reading →

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Comparing the Efficiencies of Gaussian Convolution Routines

Posted on January 25, 2011 by Taro

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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SExtractor on Debian Squeeze (AMD64)

Posted on November 30, 2010 by Taro

Installing from Debian Repository $ sudo aptitude install sextractor This version is rather old (v2.4.4) though. Installing from Source I need FFTW and ATLAS installed already, and assume that FFTW was installed at /usr/local/fftw, and ATLAS at /usr/local/atlas following the … Continue reading →

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FFTW on Debian Squeeze (AMD64)

Posted on November 30, 2010 by Taro

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)

Posted on November 30, 2010 by Taro

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 IRAF version 2.15 on Debian Squeeze

Posted on November 27, 2010 by Taro

My way of installing IRAF v2.15, now 64-bit by default. First create a regular user named “iraf”: $ sudo adduser iraf $ sudo aptitude install csh $ sudo ln -s /usr/lib/libncurses.so /usr/lib/libtermcap.so.2 The second line installing csh is necessary because … Continue reading →

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Some Physics Units Cheat Sheet

Posted on November 25, 2010 by Taro

Before I forget: In CGS: where

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