user3237: Humans use:

Pawn = 1
Knight = 3
Bishop = 3
Rook = 5
Queen = 9.5
Bishop pair = +0.5

But I would like to know what relative point values do engines use (preferably strong engines, like Stockfish, Houdini, Rybka, Komodo, ...).
If the point value that the engine assign to the pieces depends on the position of the pieces on the board (for example a White Knight on a1 is only worth 2.6 but on e5 it's worth 3.4), than I would like to know the average point values of the pieces.

user3495: I have the strong commercial chess engine Shredder Classic 4. When I open up its engine options I get the default strengths of the pieces. Without reading the documentation of this engine it seems that Shredder  starts off with the traditional piece values of queen = 9.5 pts, rook = 5 pts and so on. Then there are optional sliders where I could make any type of piece worth more or less. Interestingly the default value for a "bishop pair" can also be increased or decreased by the player. 
This seems to be about the best that I can do with Shredder to try to give an "average" strength of piece valuations.     

user118: These are the values used by Crafty - one of the best open source chess engines.
#  define PAWN_VALUE                             100
#  define KNIGHT_VALUE                           325
#  define BISHOP_VALUE                           325
#  define ROOK_VALUE                             500
#  define QUEEN_VALUE                           1050
#  define KING_VALUE                           40000

If you can follow the C code, then you can dig deeper by looking at the the source files that are available.

user15223: Rybka/Komodo/Houdini are not open source and their values aren't readily available, but the current strongest conventional engine, Stockfish, uses these values (lines 194-198):

PawnValueMg   = 126,   PawnValueEg   = 208,
KnightValueMg = 781,   KnightValueEg = 854,
BishopValueMg = 825,   BishopValueEg = 915,
RookValueMg   = 1276,  RookValueEg   = 1380,
QueenValueMg  = 2538,  QueenValueEg  = 2682,

The "Mg" column is value during the mid-game, and the "Eg" column is for the endgame. In units where the value of a pawn is 1:
Middlegame: Knight = 6.198; Bishop = 6.548; Rook = 10.127; Queen = 20.143
Endgame: Knight = 4.106; Bishop = 4.399; Rook = 6.635; Queen = 12.894
As you might guess, these numbers are empirically tuned.

3237: <p>Humans use:</p>

<ul>
<li>Pawn = 1</li>
<li>Knight = 3</li>
<li>Bishop = 3</li>
<li>Rook = 5</li>
<li>Queen = 9.5</li>
<li>Bishop pair = +0.5</li>
</ul>

<p>But I would like to know what relative point values do engines use (preferably strong engines, like Stockfish, Houdini, Rybka, Komodo, ...).</p>

<p>If the point value that the engine assign to the pieces depends on the position of the pieces on the board (for example a White Knight on a1 is only worth 2.6 but on e5 it's worth 3.4), than I would like to know the <strong>average</strong> point values of the pieces.</p>
 3495: <p>I have the strong commercial chess engine Shredder Classic 4. When I open up its engine options I get the default strengths of the pieces. Without reading the documentation of this engine it seems that Shredder  starts off with the traditional piece values of queen = 9.5 pts, rook = 5 pts and so on. Then there are optional sliders where I could make any type of piece worth more or less. Interestingly the default value for a "bishop pair" can also be increased or decreased by the player. </p>

<p>This seems to be about the best that I can do with Shredder to try to give an "average" strength of piece valuations.     </p>
 118: <p>These are the values used by <a href="http://www.craftychess.com/" rel="noreferrer">Crafty</a> - one of the best open source chess engines.</p>

<pre><code>#  define PAWN_VALUE                             100
#  define KNIGHT_VALUE                           325
#  define BISHOP_VALUE                           325
#  define ROOK_VALUE                             500
#  define QUEEN_VALUE                           1050
#  define KING_VALUE                           40000
</code></pre>

<p>If you can follow the C code, then you can dig deeper by looking at the the source files that are available.</p>
 15223: <p>Rybka/Komodo/Houdini are not open source and their values aren't readily available, but the current strongest conventional engine, Stockfish, <a href="https://github.com/official-stockfish/Stockfish/blob/master/src/types.h#L194-L198" rel="nofollow noreferrer">uses these values</a> (lines 194-198):</p>
<blockquote>
<p>PawnValueMg   = 126,   PawnValueEg   = 208,</p>
<p>KnightValueMg = 781,   KnightValueEg = 854,</p>
<p>BishopValueMg = 825,   BishopValueEg = 915,</p>
<p>RookValueMg   = 1276,  RookValueEg   = 1380,</p>
<p>QueenValueMg  = 2538,  QueenValueEg  = 2682,</p>
</blockquote>
<p>The &quot;Mg&quot; column is value during the mid-game, and the &quot;Eg&quot; column is for the endgame. In units where the value of a pawn is 1:</p>
<p>Middlegame: Knight = 6.198; Bishop = 6.548; Rook = 10.127; Queen = 20.143</p>
<p>Endgame: Knight = 4.106; Bishop = 4.399; Rook = 6.635; Queen = 12.894</p>
<p>As you might guess, these numbers are empirically tuned.</p>
