Git and RSA identities

Here is the solution I found to be able to use git with a different RSA identity than the rsa_id default one.

My repo on github is logback-android and my user account is espinielli.
I did generate an SSH key as per github help and named it github_rsa:
$ ssh-keygen -t rsa -C "your_email@youremail.com" -f github_rsa

I then added the following section in ~/.ssh/config
# github for espinielli
Host github
HostName github.com
User espinielli
IdentityFile /Users/espin/.ssh/github_rsa

From within the repo directory (I cloned it before via http):
$ git remote add gh ssh://git@github.com/espinielli/logback-android.git

And finally I am able to use it like this:
$ git push gh master

LaTeX on Blogger again

My previous post about LaTeX  on Blogger reported that the solution described there did not work anymore...
Now I found a new solution based on mathjax.

So let's try it straight away with inline math, like the great equation \(e^{-2\pi}\), and with displayed math like the following:
\[ \left [ - \frac{\hbar^2}{2 m} \frac{\partial^2}{\partial x^2} + V \right ] \Psi
= i \hbar \frac{\partial}{\partial t} \Psi \]

(What was) Croquet is maybe still alive

It seems there is still some hope to see Croquet (or, OpenCobalt which took off from where Croquet stopped) alive and based on latest Squeak and more importantly using Cog VM.
Matthew Fulmer reports it here.

The potentials are magical as explained by Howard Stearns.

Investigating Pier

I have been playing around with Pier.
It is fun, especially when you can extend it to show LaTeX formulae (this is still work in progress given I am using the js from MathJax [even if forbidden], but hey I wanted a proof of concept!)

I will try to complete it: whatch out 'Beautiful Math for Pier' on squeaksource.

LaTeX on Blogger

An inline snippet of LaTeX $e^{\pi i}+1=0\$ in blogger (from http://watchmath.com/vlog/?p=438 but it now, Oct 2010, shows crap!).


You can as well have it in display style:
\[e^{\pi i}+1=0\\]

Geomapping: what a wonderful world!

Suppose you have a set of lat/lon points, where do you find out their elevation?
Simple, let say you have the following coordinates (a cross in concrete on the top of the hill in front of my parents' place):
45.469678, 10.970527 (I got these from 'Get Directions from here' in google maps)
Then call a USGS' web service from the URL below.
It says
getElevation
for Latitude 45.46 --> Y_Value=45.469678
for Longitude 10.97 --> X_Value=10.970527
return result in meters --> Elevation_Units=METERS
use the best survey available --> Source_Layer=-1
not other additional info --> Elevation_Only=true

http://gisdata.usgs.gov/xmlwebservices2/elevation_service.asmx/getElevation?Y_Value=45.469678&X_Value=10.970527&Elevation_Units=METERS&Source_Layer=-1&Elevation_Only=true

Why would you want elevations?

To plot an elevation chart of a bike or hiking tour.

Amazing what you can find around...

(This was inspired by http://econym.org.uk/gmap/altitude.htm)

PyCalCal is out!

I finally set to put PyCalCal out in the open.
I will need to finalize and perfect it but that is a good starting point.
I also added a demo web app using it.

My idea is for PyCalCal to be used as a Python library and as such use it to provide calendrica calculations as web services.
Stay tuned if you are interested.