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Stockfish - material balance/imbalance evaluation
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Tu Ngoc Trung



Joined: 23 Feb 2012
Posts: 2
PostPost subject: Re: Stockfish - material balance/imbalance evaluation    Posted: Sun May 27, 2012 2:22 am Reply to topic Reply with quote
Sorry for my very late reply. I've recently found this topic.
I have some questions:
- In following code (current StockFish snapshot in Github), please notice code in bold format.
Code:

namespace {
  //...
  // Polynomial material balance parameters
  const Value RedundantQueenPenalty = Value(320);
  const Value RedundantRookPenalty  = Value(554);
 
  const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 };

Code:

/*
  const int QuadraticCoefficientsSameColor[][8] = {
  { 7, 7, 7, 7, 7, 7 }, { 39, 2, 7, 7, 7, 7 }, { 35, 271, -4, 7, 7, 7 },
  { 7, 25, 4, 7, 7, 7 }, { -27, -2, 46, 100, 56, 7 }, { 58, 29, 83, 148, -3, -25 } };

  const int QuadraticCoefficientsOppositeColor[][8] = {
  { 41, 41, 41, 41, 41, 41 }, { 37, 41, 41, 41, 41, 41 }, { 10, 62, 41, 41, 41, 41 },
  { 57, 64, 39, 41, 41, 41 }, { 50, 40, 23, -22, 41, 41 }, { 106, 101, 3, 151, 171, 41 } };
*/
  // Re-formatted:
  const int QuadraticCoefficientsSameColor[][8] = {
      {   7,   7,  7,   7,  7, 7 },
      {  39,   2,  7,   7,  7, 7 },
      {  35, 271, -4,   7,  7, 7 },
      {   7,  25,  4,   7,  7, 7 },
      { -27,  -2, 46, 100, 56, 7 },
      {  58,  29, 83, 148, -3, -25 } };

  const int QuadraticCoefficientsOppositeColor[][8] = {
      { 41,  41, 41,  41,  41, 41 },
      { 37,  41, 41,  41,  41, 41 },
      { 10,  62, 41,  41,  41, 41 },
      { 57,  64, 39,  41,  41, 41 },
      { 50,  40, 23, -22,  41, 41 },
      { 106, 101, 3, 151, 171, 41 } };


Please notice:
const int QuadraticCoefficientsSameColor[][8] = {
{ 7, 7, 7, 7, 7, 7 },
{ 39, 2, 7, 7, 7, 7 },
{ 35, 271, -4, 7, 7, 7 },
{ 7, 25, 4, 7, 7, 7 },
{ -27, -2, 46, 100, 56, 7 },
{ 58, 29, 83, 148, -3, -25 } };

const int QuadraticCoefficientsOppositeColor[][8] = {
{ 41, 41, 41, 41, 41, 41 },
{ 37, 41, 41, 41, 41, 41 },
{ 10, 62, 41, 41, 41, 41 },
{ 57, 64, 39, 41, 41, 41 },
{ 50, 40, 23, -22, 41, 41 },
{ 106, 101, 3, 151, 171, 41 } };
Code:

template<Color Us>
int MaterialTable::imbalance(const int pieceCount[][8]) {
  //...
  // Redundancy of major pieces, formula based on Kaufman's paper
  // "The Evaluation of Material Imbalances in Chess"
  if (pieceCount[Us][ROOK] > 0)
      value -=  RedundantRookPenalty * (pieceCount[Us][ROOK] - 1)
              + RedundantQueenPenalty * pieceCount[Us][QUEEN];

  // Second-degree polynomial material imbalance by Tord Romstad
  for (pt1 = NO_PIECE_TYPE; [b]pt1 <= QUEEN[/b]; pt1++)
  {
      pc = pieceCount[Us][pt1];
      if (!pc)
          continue;

      v = LinearCoefficients[pt1];

      for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++)
          v +=  QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2]
              + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2];

      value += pc * v;
  }


Please notice:
for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++)

Questions:
1. What is the meaning of RedundantQueenPenalty, RedundantRookPenalty and why they are used in following code?
Code:

  if (pieceCount[Us][ROOK] > 0)
      value -=  RedundantRookPenalty * (pieceCount[Us][ROOK] - 1)
              + RedundantQueenPenalty * pieceCount[Us][QUEEN];

2. What is the meaning of LinearCoefficients values?
Code:

  const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 };

3. Why do you use for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++) ? I think it should be for (pt2 = NO_PIECE_TYPE; pt2 <= QUEEN; pt2++). Because if you keep the current code, program will scan thought the arrays QuadraticCoefficientsXXX as I mentioned in blue bold format. Numbers of loop iterations will be (1+2+3+4+5+6)=21 instead of 6x6=36. And red-italic values of QuadraticCoefficientsXXX arrays will not be calculated.
4. Why do you calculate
v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2] + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2]; ?
Why not calculate
v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2] + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Us][pt2]; ?
Because the meaning of array name I understand here is Opposite color but not Opponent color.

Thanks & regards,
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Subject Author Date/Time
Stockfish - material balance/imbalance evaluation Ralph Stoesser Wed May 05, 2010 4:39 pm
      Re: Stockfish - material balance/imbalance evaluation Marco Costalba Wed May 05, 2010 4:48 pm
            Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Wed May 05, 2010 5:37 pm
                  Re: Stockfish - material balance/imbalance evaluation Marco Costalba Wed May 05, 2010 5:47 pm
      Re: Stockfish - material balance/imbalance evaluation Jan Brouwer Wed May 05, 2010 5:49 pm
            Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Wed May 05, 2010 7:25 pm
                  Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Wed May 05, 2010 8:02 pm
                        Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Wed May 05, 2010 10:10 pm
                              Re: Stockfish - material balance/imbalance evaluation Milos Stanisavljevic Wed May 05, 2010 10:30 pm
                                    Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Wed May 05, 2010 10:47 pm
                                    Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Wed May 05, 2010 11:27 pm
                                          Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Thu May 06, 2010 1:23 am
                                                Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Thu May 06, 2010 9:07 am
                                                      Re: Stockfish - material balance/imbalance evaluation Sven Schüle Thu May 06, 2010 9:31 am
                                                            Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Thu May 06, 2010 9:52 am
                                                                  Re: Stockfish - material balance/imbalance evaluation Sven Schüle Thu May 06, 2010 10:48 am
                                                                        Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Thu May 06, 2010 12:08 pm
                                                                              Re: Stockfish - material balance/imbalance evaluation Tord Romstad Thu May 06, 2010 8:24 pm
                                                      Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Thu May 06, 2010 1:19 pm
                                                Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Fri May 07, 2010 9:34 pm
                                                      Re: Stockfish - material balance/imbalance evaluation Marco Costalba Sat May 08, 2010 12:48 pm
                                                            Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Sat May 08, 2010 1:47 pm
                                                            Re: Stockfish - material balance/imbalance evaluation Marcel van Kervinck Sat May 08, 2010 2:01 pm
                                          Re: Stockfish - material balance/imbalance evaluation Marco Costalba Thu May 06, 2010 11:40 am
                              Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Wed May 05, 2010 10:42 pm
      Re: Stockfish - material balance/imbalance evaluation Joona Kiiski Wed May 05, 2010 7:54 pm
            Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Wed May 05, 2010 8:28 pm
            Re: Stockfish - material balance/imbalance evaluation Larry Kaufman Sun May 27, 2012 7:31 pm
      Re: Stockfish - material balance/imbalance evaluation Tord Romstad Thu May 06, 2010 8:16 pm
            Re: Stockfish - material balance/imbalance evaluation James Coit Thu May 06, 2010 10:13 pm
            Re: Stockfish - material balance/imbalance evaluation Vratko Polák Thu May 06, 2010 11:38 pm
            Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Fri May 07, 2010 12:15 am
                  Re: Stockfish - material balance/imbalance evaluation Marco Costalba Fri May 07, 2010 5:39 am
                        Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Fri May 07, 2010 8:09 am
                              Re: Stockfish - material balance/imbalance evaluation Marco Costalba Fri May 07, 2010 8:25 am
                                    Re: Stockfish - material balance/imbalance evaluation Sven Schüle Fri May 07, 2010 9:48 am
                                          Re: Stockfish - material balance/imbalance evaluation Sven Schüle Fri May 07, 2010 10:31 am
                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Fri May 07, 2010 10:54 am
                                          Re: Stockfish - material balance/imbalance evaluation Miguel A. Ballicora Fri May 07, 2010 10:31 pm
                                                Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Sat May 08, 2010 1:33 pm
                                                      Re: Stockfish - material balance/imbalance evaluation Marco Costalba Sat May 08, 2010 2:29 pm
                                                            Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Sat May 08, 2010 4:24 pm
                                                                  Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Sat May 08, 2010 7:54 pm
                                                                        Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Sun May 09, 2010 3:19 pm
                                                                              Re: Stockfish - material balance/imbalance evaluation Marco Costalba Sun May 09, 2010 4:47 pm
                                                                                    Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Sun May 09, 2010 7:51 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Marco Costalba Sun May 09, 2010 10:47 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Sun May 09, 2010 11:22 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Marco Costalba Mon May 10, 2010 4:58 am
                                                                                          Re: Stockfish - material balance/imbalance evaluation Sven Schüle Mon May 10, 2010 7:39 am
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Mon May 10, 2010 10:22 am
                                                                                          Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Mon May 10, 2010 5:04 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Mon May 10, 2010 9:35 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Marco Costalba Tue May 11, 2010 11:19 am
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Tue May 11, 2010 1:51 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Tue May 11, 2010 9:38 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Marco Costalba Wed May 12, 2010 5:05 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Robert Hyatt Wed May 12, 2010 6:14 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Marco Costalba Wed May 12, 2010 6:39 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Thu May 13, 2010 12:51 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Wed May 12, 2010 8:13 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Wed May 12, 2010 9:15 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Marco Costalba Wed May 12, 2010 9:34 pm
                                                                                          Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Wed May 12, 2010 10:02 pm
                                                            Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Sat May 08, 2010 4:53 pm
                                                                  Re: Stockfish - material balance/imbalance evaluation Ralph Stoesser Sat May 08, 2010 7:03 pm
            Re: Stockfish - material balance/imbalance evaluation Vincent Diepeveen Wed Jul 28, 2010 6:10 pm
                  Re: Stockfish - material balance/imbalance evaluation Milos Stanisavljevic Wed Jul 28, 2010 6:24 pm
                        Re: Stockfish - material balance/imbalance evaluation grzegorzs Thu Aug 05, 2010 5:36 pm
                  Re: Stockfish - material balance/imbalance evaluation Dann Corbit Wed Jul 28, 2010 6:43 pm
                        Re: Stockfish - material balance/imbalance evaluation Vincent Diepeveen Wed Jul 28, 2010 7:43 pm
                              Re: Stockfish - material balance/imbalance evaluation Vincent Diepeveen Wed Jul 28, 2010 7:44 pm
                                    Re: Stockfish - material balance/imbalance evaluation Joona Kiiski Wed Jul 28, 2010 7:55 pm
                                          Re: Stockfish - material balance/imbalance evaluation Vincent Diepeveen Wed Jul 28, 2010 8:30 pm
                                                Re: Stockfish - material balance/imbalance evaluation Milos Stanisavljevic Wed Jul 28, 2010 9:30 pm
                                                      Re: Stockfish - material balance/imbalance evaluation Vincent Diepeveen Wed Jul 28, 2010 10:11 pm
                                                            Re: Stockfish - material balance/imbalance evaluation Milos Stanisavljevic Wed Jul 28, 2010 10:31 pm
                                                                  Re: Stockfish - material balance/imbalance evaluation Vincent Diepeveen Wed Jul 28, 2010 10:57 pm
                                                            Crazy talk Ben-Hur Carlos Langoni Wed Jul 28, 2010 11:07 pm
                                                                  Re: Crazy talk Vincent Diepeveen Wed Jul 28, 2010 11:36 pm
                                                Re: Stockfish - material balance/imbalance evaluation Ben Stoker Wed Jul 28, 2010 10:07 pm
                                                      Re: Stockfish - material balance/imbalance evaluation Vincent Diepeveen Sun Aug 08, 2010 1:54 pm
                              Re: Stockfish - material balance/imbalance evaluation Robert Hyatt Wed Jul 28, 2010 8:27 pm
                                    Re: Stockfish - material balance/imbalance evaluation Dann Corbit Wed Jul 28, 2010 9:30 pm
                              Re: Stockfish - material balance/imbalance evaluation Wylie Garvin Tue Aug 10, 2010 10:00 pm
      Re: Stockfish - material balance/imbalance evaluation Tu Ngoc Trung Sun May 27, 2012 2:22 am
            Re: Stockfish - material balance/imbalance evaluation Ferdinand Mosca Sun May 27, 2012 10:01 am
                  Re: Stockfish - material balance/imbalance evaluation Tu Ngoc Trung Mon May 28, 2012 3:19 am
            Re: Stockfish - material balance/imbalance evaluation Eelco de Groot Mon May 28, 2012 4:19 am
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