Go to System Settings>Regional & Language > Keyboard Layout

Check Enable keyboard layouts and then go to Switching Options. After that press the button next to the text 3rd level shortcuts and select the option Right Win under the section Key to choose 3rd level. Works immediately.

I hope you find it useful.

It was written by Frederick P. Brooks, Jr.  in the 1975 after he had worked as a project manager  for the IBM System/360 computer and later for OS/360 development in the 60′s, both huge pieces of engineering for the time. Brooks tries to collect all the best practices and rules of thumb in software development and project management of complex projects that he learned during those experiences.

The anniversary edition (2nd edition), the one I’ve read, includes a few new chapters besides the original essay. Those are the No Silver Bullet (which itself would need another post) and a few others that review the propositions of the book some time later.

In this post I’m going to highlight a few things I liked about the book as a reminder to my future self. The bellow bullet points are  fragments from the book (in italics) followed by my comments about them.

• The man-month is a fallacious and dangerous myth, for it implies that men and months are interchangeable. This is the argument that gives title to the book. Many tasks during the development of a program cannot be partitioned due to its inherent sequential constraints and even when tasks could be carried in parallel there is always an overhead in communication between workers.
• Brooks’s Law:  Adding manpower to a late software project makes it later. This is a consequence of all the communication that is generated and all the time needed to train the new people.
• All programmers are optimists. Thank god it wasn’t just me.
• Conceptual integrity is the most important consideration in system design. To achieve it, the design should proceed from one mind or a small group of minds.
• The second is the most dangerous system a person ever designs; the general tendency is to over-design it. As normally an architect has not the confidence to implement all the ideas that come up to him during its first design. During his second design, an architect will try to implement all the stored ideas from his first design.
• Plan to throw one away, you will anyway. It is very important to prepare the design for changes because valid changes in objectives may certainly arise during development.
• How does a project get to be a year late? … One day at a time. Brooks gives some great advices about preventing a schedule slippage.

There are many other interesting topics in the book like the importance of communication and organization of groups or how to scale small groups to design and implement large systems.

Overall it is a very good book even if you aren’t really interested in software management.

sudo sed -i~ ‘/xkb_symbols “ralt_switch” {/a  include “level3(rwin_switch)”‘ /usr/share/X11/xkb/symbols/level3

This makes the right Apple key to work as Alt Gr.I found it here.

DON’T DOWNLOAD THEM! Unless of course you are

a developer or take great pleasure in incomplete,

unpredictable, and potentially crashing software.

So, I downloaded the ubuntu package from their dev channel and after a while trying it I found it very satisfactory.

From the things that doesn’t work yet the one I miss the most is the flash plugin. If your language is other than English you’ll find that input methods doesn’t work neither (no accents for now). Besides the missing features I haven’t had a single crash (yet) or any rendering issue. Web pages with javascript seems to go fast but not surprisingly fast, maybe I was expecting too much.

I guess there might be many blogs out there with good reviews of the Windows version, so I’ll just show a few snapshots I took.

New tab

The above picture shows how a new tab looks. As you can see it shows the most visited pages and the recently bookmarked and recently closed ones. It is still not possible to manage bookmarks or to add a bookmark bar.

Incognito mode

Por…, I mean, Incognito mode already works

Find in page

Something that bothered me at first is that the find in page bar is located at the right upper corner.

Omnibox

Omnibox is working although it is not possible yet to configure the search engines.

Download manager

I like the clean look of the download manager.

A lot of configuration options are still missing but my conclusion is that it’s nearly usable for every day use. I just wonder why it took so much time for Google to develop the Mac and Linux versions. Was it just because of technical difficulties? Was it a lack of interest? Or a mix of both?

1. Any live cell with fewer than two live neighbours dies, as if caused by underpopulation.
2. Any live cell with more than three live neighbours dies, as if by overcrowding.
3. Any live cell with two or three live neighbours lives on to the next generation.
4. Any dead cell with exactly three live neighbours becomes a live cell.

It’s amazing to see the amount of literature available about this game. You can check the wikipedia article for an example.

So, a few weeks ago our professor on High Performance Computating challenged us to implement a Game of Life without if statements. The difficulty lies in all the special cases to take into account when you use a matrix data structure to represent the cells. The special cases are those cells that have less adjacent neighbours than the normal cells, like corners and cells in the borders of the matrix. Avoiding conditional branches inside large loops is usually a very good practice to improve the performance of your code, since a branch instruction is a very costly operation for the cpu.

The challenge itself wasn’t very difficult, so a few weeks ago when I was bored I decided to implement it using Qt 4 toolkit. It was also an excuse to try the new QtCreator IDE, which, by the way, I found amazing.

Let’s take a look at my solution:

void GameOfLifeWidget::setMatrices()
{
    m_lifeMatrix = new int*[ m_rows + 2 ];
    m_nextMatrix = new int*[ m_rows + 2 ];
    for( int i = 0; i < m_rows + 2; i++ )
    {
        m_lifeMatrix[i] = new int[ m_cols + 2 ];
        m_nextMatrix[i] = new int[ m_cols + 2 ];
        for( int j = 0; j < m_cols + 2; j++ )
        {
            m_lifeMatrix[ i ][ j ] = 0;
            m_nextMatrix[ i ][ j ] = 0;
        }
    }
}

void GameOfLifeWidget::iterate()
{
    int neighbours = 0;
    int **aux;
    int currCell;
    for( int i = 1; i < m_rows; i++ )
    {
        for( int j = 1; j < m_cols; j++ )
        {
            neighbours = m_lifeMatrix[ i - 1 ][ j - 1 ] + m_lifeMatrix[ i ][ j - 1] +
                         m_lifeMatrix[ i + 1 ][ j - 1 ] + m_lifeMatrix[ i - 1 ][ j ] +
                         m_lifeMatrix[ i + 1 ][ j ] + m_lifeMatrix[ i - 1 ][ j + 1 ] +
                         m_lifeMatrix[ i ] [ j + 1 ] + m_lifeMatrix[ i + 1 ][ j + 1 ];
            currCell = m_lifeMatrix[ i ][ j ];
            m_nextMatrix[ i ][ j ] = !( currCell == 1 && ( neighbours   3 ) ) &&
                                    ( currCell == 0 && neighbours == 3 );            

        }

    }
    aux = m_lifeMatrix;
    m_lifeMatrix = m_nextMatrix;
    m_nextMatrix = aux;
    update();
}

To avoid the special cases we can create a matrix with extra borders. We will never iterate over these borders, but they make the actual borders a common case with 8 adjacent neighbours just like every other cell.

The method iterate is called every 500 milliseconds and it calculates the matrix of cells  for the next iteration. It does so by looping through the matrix and counting the number of neighbours for every cell. Then it applies AND’s and OR’s operations that combine the 4 rules of the game to find out if the cell must live or die.

And now the mandatory snapshot:

Game of Life Snapshot

You can also download the source code from here and, if you can make it compile, spend hours watching how life evolves.

Note: There is an issue with Qt re-painting the whole grid on every iteration which makes the cpu go high, I know why it happens but I haven’t had the time to fix it, but you can do whatever you want since it’s GPL

Last night I had the dream again and it was very convincing. The funny part comes when in the dream I have this talk with a friend.

- Hey, do you remember that dream I told you about going back to high school?

- Yeah, I do, you’ve told it so  many times.

- Yeah, I know, But this time it came true!!! I told you it would happen someday.

GEB Recursive

It was such a relief when I woke up.

Today I come with some nice stuff I’ve done recently. The first one is a nice user feedback by highlighting the context pages under the mouse in zoom out mode. Easy to implement and nice to have.

Context highlighting

The other nice stuff is the current track showing the last tracks played when in stopped state.

Last played tracks

It’s a little update but helps me to get back to work.

The organization of the event was perfect, there were many interesting talks, it’s a shame I’ve had to miss some of them. The social event sponsored by Nokia and the boat trip today were really really awesome (free beer, free food, what else could you ask?).

The only bad thing was that it was not really very productive in terms of code but it was really helpful to meet some of the plasma guys who were really kind to me and helped me a lot.

What was also very cool was the n810 that Nokia gave to some of us (a lot of us). It has become the favorite toy arround akademy. It would be really nice to have amarok playing on one of those with an adapted UI for the touch screen. Maybe someday, who knows ?

As for the Summer of Code program, well, it’s coming to an end and I still have lots of things to do, what is making me feel a little bit worried. I’ll have keep coding after deadline (18th august) to go as further as I can.

No snapshots this week, sorry

Toolbox menu

Toolbox

The menu appears after clicking in the plus icon in the toolbox. If you click in one of the entries of the menu it adds the applet to the current containment or, if the applet was already added, it takes you to the containment where the applet is. There isn’t the possibility of removing an applet from this menu but it’s something that I’m not sure that we want/need from this menu, I wanted to keep it simple so we will see what happens.

I’ve also changed the toolbox look a little bit, added some animations here and there and did some refactoring and a lot of changes in the code. Oh, and you may also have noticed that there has been a lot of visual changes in the application. This is because we have Nuno Pinheiro collaborating as an artist. Thanks to Pinheiro we now have our new own plasma theme as you may have noticed in the Context View. The current track applet doesn’t look so well now and we will probably need to redesign the applet to fit with the new theme.

In a few hours I’m taking a plane to Belgium to attend to aKademy. It will be a week of hacking that I hope will be very productive. See you soon.

I delayed the post publication a few days to have it a little bit more polished and to prepare markey’s birthday present. The present comes a little bit late but I know you’ll like it markey:

New ContextView toolbox and markey's birthday present

I hope you like. Sorry for the short post, more updates and snapshots after the weekend.