Aug 16

Running stockfish or komodo on Centos 6

I wanted to try out a chess engine, but I didn't want to run it on my own computer where I have the GUI. So what to do? I had a centos 6 computer with enough cpu power, but when I downloaded and ran stockfish I got:

$ ./stockfish-7-linux/Linux/stockfish\ 7\ x64 
./stockfish-7-linux/Linux/stockfish 7 x64: /lib64/libc.so.6: version `GLIBC_2.14' not found (required by ./stockfish-7-linux/Linux/stockfish 7 x64)
./stockfish-7-linux/Linux/stockfish 7 x64: /lib64/libc.so.6: version `GLIBC_2.17' not found (required by ./stockfish-7-linux/Linux/stockfish 7 x64)

And when I ran komodo 10.1 (which you have to buy), I got:

$ ./komodo-10.1-linux 
./komodo-10.1-linux: /lib64/libc.so.6: version `GLIBC_2.14' not found (required by ./komodo-10.1-linux)
./komodo-10.1-linux: /usr/lib64/libstdc++.so.6: version `GLIBCXX_3.4.15' not found (required by ./komodo-10.1-linux)

The problem is Centos 6 has too old glibc version. So how to fix this? The short version is to download the finished files I'll show you how to create in the long answer. They are ld-linux-x64-64.so.2, libc.so.6 and libstdc++.so.6.

Short answer:

wget http://www.menneske.no/libs/chesslib.tar.gz
tar zxvf chesslib.tar.gz
./ld-linux-x86-64.so.2 --library-path . <path to komodo or stockfish>

Voila, they both works fine on Centos 6.

Long answer:
For stockfish you can download the src and compile it. But for komodo that is not possible. So, you need to compile both gcc and glibc to be able to get the files. It takes a long time, and some GB of space, but here is how you do it, if you don't trust my precompiled files:

# First we assure we have the development tools to build stuff
yum groupinstall "Development tools"
yum install -y glibc-devel glibc-i686

# Now we build glibc. This will not overwrite your current glibc, so don't worry
cd /tmp
wget http://ftp.gnu.org/gnu/glibc/glibc-2.17.tar.gz
tar -xvzf glibc-2.17.tar.gz
cd glibc-2.17
mkdir glibc
cd glibc
../configure --prefix='/opt/glibc-2.17'
make install

# Then compile gcc
cd /tmp
wget ftp://ftp.gwdg.de/pub/misc/gcc/releases/gcc-4.6.4/gcc-4.6.4.tar.gz
tar -xvzf gcc-4.6.4.tar.gz
cd gcc-4.6.4
mkdir objdir
cd objdir
../configure --prefix=/opt/gcc-4.6.4
make install

Now we have all the files, and we copy them out to our preferred directory.

cd <your path>
cp /opt/gcc-4.6.4/lib64/libstdc++.so.6 .
cp /opt/glibc-2.17/lib/libc.so.6 .
cp /opt/glibc-2.17/lib/ld-linux-x86-64.so.2 .

And then you run it with:

./ld-linux-x86-64.so.2 --library-path . <path to komodo or stockfish>

But how did I reach it from my other computer? Well, ssh to the resque.

cat <<EOT > komodo
# ssh chess.test.com -l chess ./ld-linux-x86-64.so.2 --library-path . <path to komodo or stockfish>
ssh <yourhost> -l <youruser> <path to komodo on host>

# fix permissions
chmod 750 komodo

Remember to add pub ssh key to the host, so you don't need to write the password to login. Voila, then you just add "komodo" as the engine in your favourite GUI.

Jan 16

#FreeFreddy puzzle game is out

Cellar Labs new puzzle game, Free Freddy, is out for Android. Get it at Google Play.

Solve 100 puzzles to earn trophies and certificates. Or try solve random puzzles in different sizes and difficult levels. If you feel lucky, try a 10x10 insane puzzle.

The game will soon be available for iPhone and Windows Phone too.


Get it on Google Play

Get it from Microsoft

Nov 15

phaser-swipe for #phaser.io

I've created a swipe component for Phaser.io. You can find it on GitHub

You can grab the swipe.js file and include it in your project, or you can use npm or bower:

   npm install phaser-swipe
   bower install phaser-swipe


You can use it in two ways. With or without a model. This is without model

  var Swipe = require('phaser-swipe');
  // in create
  this.swipe = new Swipe(this.game);
  // in update
  var direciton = this.swipe.check();
  if (direction!==null) {
    // direction= { x: x, y: y, direction: direction }
    switch(direction.direction) {
       case this.swipe.DIRECTION_LEFT: // do something
       case this.swipe.DIRECTION_RIGHT:
       case this.swipe.DIRECTION_UP:
       case this.swipe.DIRECTION_DOWN:
       case this.swipe.DIRECTION_UP_LEFT:
       case this.swipe.DIRECTION_UP_RIGHT:
       case this.swipe.DIRECTION_DOWN_LEFT:
       case this.swipe.DIRECTION_DOWN_RIGHT:

This is with a model. Here you define your methods in your model. Only those methods defined will be used. So if you do not want the diagonals, you can just omit those methods.

   function YourModel() {
      up: function(point) {},
      down: function(point) {},
      left: function(point) {},
      right: function(point) {},
      upLeft: function(point) {},
      upRight: fuction(point) {},
      downLeft: function(point) {},
      downRight: fuction(point) {}
   // in create
   this.swipe = new Swipe(this.game, yourmodel);
   // in update. The methods will only be called if you have a swipe.
   // point: { x: x, y: y }
Nov 15


I created an animated updatable label for the Javascript framework Phaser.io. You can find it on github.

You can use it like:

 // If you used browerify. Else just add it in script tag and use class UpdatableLabel.
  var UpdatableLabel = require('phaser-updatable-label');

  // Sample style for the label text
  var textStyle = { font: '50px Arial', fill: '#00', align: 'center'};

  // The initial value of the label
  var initValue = 0;

  // Create the label. The true is to set if the label is ment to be positive
  var label = new UpdatableLabel(this.game, startX, startY, initValue, textStyle, true);

  // Add a value to the label. We define the start position for the value we add
  // This will start the animation and add the value
  label.addValue(10, {x: 100, y: 100});

  // Get the new value. This is the updated value even though the label is not
  var newValue = label.getValue();

  // We can also add multiplications. If the value was 1 and we add multiplier by 2
  // the new value will be 2
  label.addMultiplier(value, {x: 100, y: 100});

  // And remove it. The module take care of correct number, so you should use
  // the value of 2 if you used 2 in addMultiplier
May 15

Solution to Vietnamese pesky snake in #perl

I got a link to the Vietnamese Pesky Snake math problem from my wife. (http://m.db.no/2015/05/21/nyheter/utenriks/matematikk/oppgave/39292707/) And as a programmer, I couldn't really sit there and solve it with my bare hands. Ok, I admit it's fun to solve math problems, but this was very much looking like a problem with more than one solution, and I needed to know for sure 🙂

So I created a little program in perl to solve this. It's located at gist: https://gist.github.com/flogvit/ba6e984236f9b4e08c10

And for those wondering, yes, it had several solutions, actually 128 of them.