Why can't numpy do duplicate index assignment

AG

I want to do drizzling with numpy. It should be trivial, but it's impossible (without a for loop, afaik) instead.


In [2]: a = array([1,1,2,2])

In [3]: b = arange(5)

In [4]: b[a] += 1

In [5]: b
Out[5]: array([0, 2, 3, 3, 4])

In [6]: # but b should really be:

In [7]: b[a] += 1

In [8]: b
Out[8]: array([0, 3, 4, 3, 4])


pyspeckit: an astronomical spectroscopic toolkit

Jordan and I have been working on our python-based spectroscopic analysis tool for a while now:
pyspeckit is a pretty awesome, now functional but incomplete (and incompletely documented) tool.

pstopng

Following this thread and my need to convert IDL .ps files to .pngs so that I can view them in Mac Preview without having to go through an (often failed) conversion process led to a few discoveries.

First, it is challenging to get ImageMagick's convert to make an opaque background for the .ps file without seriously degrading the resolution. This can be accomplished by passing both the -alpha Off and the -density 300 simultaneously. This is slow, though, and recommendations to speed it up using the -limit area 4096 -limit memory 4096 tags actually made it slower!

However, the thread pointed out that ghostscript can do the conversion directly:
gs -dBATCH -sDEVICE=png16m -r300 -dEPSCrop -dNOPAUSE -sOutputFile=XXX.png XXX.ps

-sDEVICE sets the output to png, -r300 tag sets the density to be 300 pixels/inch, -dEPSCrop is necessary to get the right sized image out (otherwise it defaults to a portrait 8.5x11), and -dBATCH prevents the gs command line from activating after the command is executed. I'm not sure if -dNOPAUSE is necessary, but apparently if you don't activate it you have to do something after every page is processed.

My code to do batch ps-to-png conversion is available at http://code.google.com/p/agpy/source/browse/trunk/agpy/pstopng.

Timing demonstrations (units are seconds, R is 'real' or clock time, 'U' is user time, and 'S' is system time):

/usr/local/bin/convert -density 300 -alpha Off deline_zero_10hz_timestreams_003.ps deline_zero_10hz_timestreams_003.png
TIMING: R: 3.126 U: 2.948 S: 0.084
/usr/local/bin/convert -limit area 4096 -limit memory 4096 -density 300 -alpha Off deline_zero_10hz_timestreams_003.ps deline_zero_10hz_timestreams_003.png
TIMING: R: 3.800 U: 2.970 S: 0.161
gs -dBATCH -sDEVICE=png16m -r300 -dEPSCrop -dNOPAUSE -sOutputFile=deline_zero_10hz_timestreams_003.png deline_zero_10hz_timestreams_003.ps
TIMING: R: 0.801 U: 0.781 S: 0.017


Converting GILDAS-CLASS data cubes (lmv files) to fits

As usual, CLASS documentation is nearly impossible to navigate. At the end of the CLASS "introduction" (gildas-intro.pdf) there is a subtle and obscure reference to the vector\fits command. The conversion is actually relatively straightforward:

vector\fits outfile.fits from infile.lmv



AG

IDL syntax highlighting in VIM

I've edited my idlang.vim to auto-identify files that start with a semicolon.

Add Line 19:
syn match idlangStatement "^\s*;\s"

Line 61/2 (allow spaces before ;):
syn match idlangComment "\s*[\;].*$" contains=idlangTodo


AG

Mercurial - behave like SVN?

I'm trying to use hooks to make mercurial behave like svn when committing. I like the idea that I can commit changes to my cloned repo while I'm away from the internet, but I never want that behavior when I do have internet access. Therefore, I want to attempt to pull before updating and attempt to push after committing. Every time. I have been consistently very unhappy with the hg merge command.


[hooks]
precommit = hg pull; hg up
postcommit= hg push
post-pull = hg up


However, this doesn't work. precommit freezes with the error
waiting for lock on working directory of [dir] held by [procnum]

and pre-commit results in other errors:

running hook pre-commit: hg pull; hg up
pulling from [source]
searching for changes
no changes found
running hook post-pull: hg up
abort: outstanding uncommitted merges
warning: post-pull hook exited with status 255
abort: outstanding uncommitted merges
warning: pre-commit hook exited with status 255


AG

Repositories for observers

I should have posted these a while ago....
casaradio is a subversion repository for folks at The Center for Astrophysics and Space Astronomy at CU Boulder to post radio astronomy related codes. So far, emphasizes single dish (GBT, Arecibo), but will include EVLA, CARMA, and ALMA eventually.
aposoftware is a similar page, but is a mercurial repository and is meant to include instrument-specific software for the Apache Point Observatory 3.5m telescope. Right now includes a TUI script or two and the TSPEC and DIS IRAF-twodspec pipelines.

I'd be remiss to leave out the BGPS pipeline even though it's mentioned on the previous post.

Also, agpy is my personal code repository.