Answers.Body: <p>What you're doing here is not correct and definitely not what a chess engine is designed for. You're running multi-pv analysis with many many lines. Multi-PV with many lines as in in your example is exponentially slower than a single-PV analysis. In an N multi-PV analysis, the engine would need to examine the first PV then ignore it for the next best PV. And this continues until all PVs are examined. This is very slow when you do it in iterative deepening where the search tries deeper by each iteration.</p>
  
  <p>Also, the position is tricky for an engine because it has too many captures. When you're in a very tactical full-blown position, the engine would need to expand its qsearch so to get to the bottom of the search tree.</p>
  
  <p>In summary, what you're doing here doesn't make any sense. You'll need to scale down your lines.</p>
  
  <p>Your lines are not sorted is the fault of the user interface and not the engine.</p>
  
  <p>Please read <a href="http://www.cruxis.com/chess/manual/index.html?game_play.htm" rel="nofollow">http://www.cruxis.com/chess/manual/index.html?game_play.htm</a> for the Tactical Mode. You'll need to send that UCI command to Houdini.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-07-23T01:55:44.850Z
Answers.Text: For the "Tactical Mode", I can't find it on my Houdini 3... And for the "Mate Search", it doesn't seem to work... When I click on it, and then click on "Ok" it does nothing (and when I click on "Parameters" it does nothing either).
Answers.UserDisplayName: Fate
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-07-23T03:34:07.833Z
Answers.Text: Which GUI are you using?
Answers.UserDisplayName: SmallChess
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-07-23T03:48:38.503Z
Answers.Text: The Fritz/ChessBase GUI.
Answers.UserDisplayName: Fate
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-07-23T01:41:33.353Z
Answers.LastActivityDate: 2014-07-23T01:41:33.353Z
Answers.UserDisplayName: SmallChess
Body: <p>I noticed that when I put my Houdini 3 Pro x64 in the "Infinite Analysis" mode, he tends to use a lot of time to evaluate the bad moves... Sometimes he even uses like 30 seconds on the first 10 best moves on his list, but then he uses like 5 minutes on the other (bad) moves... He meditates for a lot of time on the last few moves in his list, even though they are just stupid moves that give up the Queen for nothing...</p>
  
  <p>I made him analyze the following position:</p>
  
  <p><img src="https://i.sstatic.net/Pp02q.jpg" alt="enter image description here"></p>
  
  <p>And he needed 2 hours to find the forced mates...</p>
  
  <p><img src="https://i.sstatic.net/ukt6z.png" alt="enter image description here"></p>
  
  <p>And also, while he was analyzing the position, his list of moves was all messed up: the moves were not ordered according to their evaluations (the best moves should be first, while the worst moves should be last... but it was not the case). Although after he finally found the forced mates he then ordered the moves correctly. Oh and he found that ...Nc6 was a mate in 19 <strong>before</strong> finding that ...exf6 was a mate in 6.</p>
  
  <p>So is my Houdini broken or something?</p>
  
  <p>And I heard that to find forced mates there was a quicker way: there exist a special mode which puts the engine into a "mate search mode". But how can I put my Houdini in that mode?</p>
  
Tags: <analysis><engines><checkmate><evaluation><houdini>
Title: Is my engine working properly?
ThreadText: # Is my engine working properly?
  
  (Asked by: username_0 on 2014-07-23)
  
  I noticed that when I put my Houdini 3 Pro x64 in the "Infinite Analysis" mode, he tends to use a lot of time to evaluate the bad moves... Sometimes he even uses like 30 seconds on the first 10 best moves on his list, but then he uses like 5 minutes on the other (bad) moves... He meditates for a lot of time on the last few moves in his list, even though they are just stupid moves that give up the Queen for nothing...
  
  I made him analyze the following position:
  
  ![enter image description here](https://i.sstatic.net/Pp02q.jpg)
  
  And he needed 2 hours to find the forced mates...
  
  ![enter image description here](https://i.sstatic.net/ukt6z.png)
  
  And also, while he was analyzing the position, his list of moves was all messed up: the moves were not ordered according to their evaluations (the best moves should be first, while the worst moves should be last... but it was not the case). Although after he finally found the forced mates he then ordered the moves correctly. Oh and he found that ...Nc6 was a mate in 19 **before** finding that ...exf6 was a mate in 6.
  
  So is my Houdini broken or something?
  
  And I heard that to find forced mates there was a quicker way: there exist a special mode which puts the engine into a "mate search mode". But how can I put my Houdini in that mode?
  
  **Tags:** analysis, engines, checkmate, evaluation, houdini
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2014-07-23. Score: 4 | Accepted answer
  
  What you're doing here is not correct and definitely not what a chess engine is designed for. You're running multi-pv analysis with many many lines. Multi-PV with many lines as in in your example is exponentially slower than a single-PV analysis. In an N multi-PV analysis, the engine would need to examine the first PV then ignore it for the next best PV. And this continues until all PVs are examined. This is very slow when you do it in iterative deepening where the search tries deeper by each iteration.
  
  Also, the position is tricky for an engine because it has too many captures. When you're in a very tactical full-blown position, the engine would need to expand its qsearch so to get to the bottom of the search tree.
  
  In summary, what you're doing here doesn't make any sense. You'll need to scale down your lines.
  
  Your lines are not sorted is the fault of the user interface and not the engine.
  
  Please read <http://www.cruxis.com/chess/manual/index.html?game_play.htm> for the Tactical Mode. You'll need to send that UCI command to Houdini.
  
  > **Comments:**
  > **username_0**: For the "Tactical Mode", I can't find it on my Houdini 3... And for the "Mate Search", it doesn't seem to work... When I click on it, and then click on "Ok" it does nothing (and when I click on "Parameters" it does nothing either).  
  > **username_1**: Which GUI are you using?  
  > **username_0**: The Fritz/ChessBase GUI.  
  
  ---
  
  