Musings from a Sunday morning

In the last Sunday of 2013 and I was holding David in my left arm (then a two months old baby) while he was slipping. It was a normal morning with Sara (two years and one week older than her brother) wandering and running all over the place.

Since I had only one hand available and I had to stay still I decided to read some rss feedings. In one of them, that I now forget the source, I was redirected to this gcc bug report titled "__cplusplus defined to 1, should be 199711L".

The amusing part, at least to me, was that it has taken more than 10 years to close the bug. The bug was opened on 2001-01-25 for version 2.97 and finally closed and fixed on 2011-08-18 for gcc 4.7. The whole bug report is an entertaining reading and really appropriated for Saturday morning in the Christmas holidays (just 129 comments).

The interesting part was that the change was withheld  by the solaris port of gcc. While I suspect that although an important reason the bug was not overly urgent or else the social pressure to fix it would had justified a quicker action.

The musing part was twofold, on one hand how free(/libre) software works and one of the reasons why I enjoy it, the cooperation and the ideas exchange. The second reason was for being a Sunday with Susana, that understands and uses free software, and the two kids who (at least for now) could not care less about software as a social experience. Surely this inspires me with a smile and hope in the humanity.

I love daddy

Sara's t-shirt on this picture said "i ♥ daddy!". As an impartial observer I can say that Sara's happy face reflects that. ;-)

12 anos

Pois é, parabéns a mim por aturar a Xana durante tanto tempo. :-)

Tem sido uma jornada e pêras. Vale a pena, mesmo.

Teste em 2011

Estou a escrever a partir do meu telemóvel. Claramente estamos em 2011. :-)
No ano que se passou desde a última mensagem não se passou nada se não contarmos vários acontecimentos como o nascimento da Sara.

Interessante: Vivian Maier - Her Discovered Work

Enquanto lia o Internet Scout Report encontrei uma referência à obra de uma fotografa de rua quase desconhecida cujo trabalho só parece estar a ser verdadeiramente apreciado depois da sua morte em 2009.

O trabalho pode ser apreciado blog criado para o efeito pelo caramelo que comprou o espólio num leilão em Chicago onde ela morou a maior parte da sua vida.

São fotografias muito interessantes e que de alguma forma me fazem lembrar a poesia do Fernando Namora.

Python class for quaternions

Last August in Dublin (at DCU) I presented a tutorial about Python in Scientific Computing.

While there I thought it was appropriate to give a native example (in Rome be Roman) and so I choose the Quaternions. This is a good excuse as any other to present the multiple features of python for science. :-)

The picture above is carved in the Broom Bridge, over the Royal Canal, and where supposedly Hamilton had the inspiration to come with such beasts :-) . I had described before (in Portuguese) my hazard quest to find the place. An yearly event, at 16th of October, gets people together to visit the place and probably for a couple of drinks. :-)

While preparing the course I searched for python implementations of the quaternions and I have only found code related with graphics transforms (where the quaternions can be useful).
In the same spirit of Free/Open Source Software, to scratch a itch, I make available my implementation of  a python class that implements the quaternions and that deals transparently with the complex numbers.

The code can be found at my homepage.

Here it is a sample:

    a = Quaternion(1, -2)
    b = Quaternion(1, 2, -3, 4)
    c = 1 - 2j

    print "a =", a
    print "b =", b
    print "c =", c

    print a + b
    print a - c

    print a*b
    print a*c

    print 2*a

    print b*b.conjugate()
    print abs(b)**2

And the resulting output:

a = +1-2*i+0*j+0*k
b = +1+2*i-3*j+4*k
c = (1-2j)
+2+0*i-3*j+4*k
+0+0*i+0*j+0*k
+5+0*i+5*j+10*k
-3-4*i+0*j+0*k
+2-4*i+0*j+0*k
+30+0*i+0*j+0*k
30.0

I hope this helps others who have the same problem I had. :-)

Fedora: an auspicious name

I have stated several times before that Fedora is strange name in Portuguese. Imagine my surprise when walking in Lisbon at "Rua Aurea" I got the following view. "Bijuterias" the name after Fedora means costume jewelry.

For what is worth this post has been delayed one year since the last time I was there I only had my mobile phone camera (not terribly accurate). Now with a real camera the result is worth to show.

Equally interesting is that "Rua Áurea" can be translated as "Golden Street". The street that follows it is "Rua do Ouro", Gold Street.
The streets at that area of Lisbon were rebuilt after the 1755 major earthquake, and the resulting tsunami that followed it, that totally destroyed that area. The streets at that area were named after the particular trade practiced there (a common practice in medieval Europe).

A posteriori (as opposed to "a priori") the relevance of this poster can be attributed to the next release of Fedora. Fedora 14 release will happen (we hope) next Tuesday, 2nd of November the day next  to the anniversary of Lisbon earthquake. Let us hope for this to be a (benign) earthquake in OS landscape.