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Finds a Character based on distance and health

Finds a Character based on distance and health

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;

1

$begingroup$

I need to improve the efficiency of my program and, using the profiler, have narrowed the problem down to 2 key areas, but I am having trouble coming up with ways to make the program run better.

Based on my profiler's report, it seems to be telling me that my if functions are inefficient. Whats a better way to achieve a better result?

Character* FindAttackTarget() const
 
 float weakestHp = FLT_MAX;
 Character* weakestEnemy = nullptr;
 uint64_t weakestCharId = INT64_MAX;

 //Only attack characters that are within attack range
 auto& gameChars = m_pGame->m_gameCharacters;


 for (size_t i = 0; i < gameChars.size(); ++i)
 
 auto& c = gameChars[i];
 if (Location.Dist(c.GetLocation()) <= AttackRange &&
 c.HP > 0 &&
 c.Team != Team)
 
 

 return weakestEnemy;
 

c++ performance

share|improve this question

asked 4 hours ago

AtazirAtazir

61

New contributor

Atazir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Which lines are the ones being flagged by the profiler as slow?
  $endgroup$
  – 1201ProgramAlarm
  1 hour ago
  

  
  
  
  

add a comment | 

1

$begingroup$

I need to improve the efficiency of my program and, using the profiler, have narrowed the problem down to 2 key areas, but I am having trouble coming up with ways to make the program run better.

Based on my profiler's report, it seems to be telling me that my if functions are inefficient. Whats a better way to achieve a better result?

Character* FindAttackTarget() const
 
 float weakestHp = FLT_MAX;
 Character* weakestEnemy = nullptr;
 uint64_t weakestCharId = INT64_MAX;

 //Only attack characters that are within attack range
 auto& gameChars = m_pGame->m_gameCharacters;


 for (size_t i = 0; i < gameChars.size(); ++i)
 
 auto& c = gameChars[i];
 if (Location.Dist(c.GetLocation()) <= AttackRange &&
 c.HP > 0 &&
 c.Team != Team)
 
 

 return weakestEnemy;
 

c++ performance

share|improve this question

asked 4 hours ago

AtazirAtazir

61

New contributor

Atazir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Which lines are the ones being flagged by the profiler as slow?
  $endgroup$
  – 1201ProgramAlarm
  1 hour ago
  

  
  
  
  

add a comment | 

$begingroup$

I need to improve the efficiency of my program and, using the profiler, have narrowed the problem down to 2 key areas, but I am having trouble coming up with ways to make the program run better.

Based on my profiler's report, it seems to be telling me that my if functions are inefficient. Whats a better way to achieve a better result?

Character* FindAttackTarget() const
 
 float weakestHp = FLT_MAX;
 Character* weakestEnemy = nullptr;
 uint64_t weakestCharId = INT64_MAX;

 //Only attack characters that are within attack range
 auto& gameChars = m_pGame->m_gameCharacters;


 for (size_t i = 0; i < gameChars.size(); ++i)
 
 auto& c = gameChars[i];
 if (Location.Dist(c.GetLocation()) <= AttackRange &&
 c.HP > 0 &&
 c.Team != Team)
 
 

 return weakestEnemy;
 

c++ performance

share|improve this question

asked 4 hours ago

AtazirAtazir

61

New contributor

Atazir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

Character* FindAttackTarget() const
 
 float weakestHp = FLT_MAX;
 Character* weakestEnemy = nullptr;
 uint64_t weakestCharId = INT64_MAX;

 //Only attack characters that are within attack range
 auto& gameChars = m_pGame->m_gameCharacters;


 for (size_t i = 0; i < gameChars.size(); ++i)
 
 auto& c = gameChars[i];
 if (Location.Dist(c.GetLocation()) <= AttackRange &&
 c.HP > 0 &&
 c.Team != Team)
 
 

 return weakestEnemy;
 

share|improve this question

asked 4 hours ago

AtazirAtazir

61

New contributor

Atazir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this question

asked 4 hours ago

AtazirAtazir

61

New contributor

Atazir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 4 hours ago

AtazirAtazir

61

New contributor

Atazir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 4 hours ago

AtazirAtazir

61

1 Answer
1

active

oldest

votes

2

$begingroup$

The tests c.HP > 0 and c.Team != Team are probably blazingly fast tests. Location.Dist(c.GetLocation()) <= AttackRange probably involves the square-root of the sum of the squares of the difference of coordinates in two or three dimensions. Plus, GetLocation() may involve memory allocation and/or copying constructors. It is by far the slowest test, yet you are testing it first! Take advantage of the short-circuit logical and operators by reordering the tests so the fastest tests are done first, so the slowest test may not even need to be executed, resulting in faster execution.

Bonus: the square-root can be avoided; simply compute the square distance, and compare against the $AttackRange^2$ (computed outside of the loop) for another speed gain.

share|improve this answer

answered 1 hour ago

AJNeufeldAJNeufeld

7,0541723

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I believe you're on the right track but could expand and systematize your answer: for instance, @Atazir could have gameChars partitioned between enemy and the rest, then have the enemy partition sorted by strength, and last find the first enemy in range: the costly operation is performed on the least number of elements.
  $endgroup$
  – papagaga
  44 mins ago
  

  
  
  
  

add a comment | 

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2

$begingroup$

The tests c.HP > 0 and c.Team != Team are probably blazingly fast tests. Location.Dist(c.GetLocation()) <= AttackRange probably involves the square-root of the sum of the squares of the difference of coordinates in two or three dimensions. Plus, GetLocation() may involve memory allocation and/or copying constructors. It is by far the slowest test, yet you are testing it first! Take advantage of the short-circuit logical and operators by reordering the tests so the fastest tests are done first, so the slowest test may not even need to be executed, resulting in faster execution.

Bonus: the square-root can be avoided; simply compute the square distance, and compare against the $AttackRange^2$ (computed outside of the loop) for another speed gain.

share|improve this answer

answered 1 hour ago

AJNeufeldAJNeufeld

7,0541723

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I believe you're on the right track but could expand and systematize your answer: for instance, @Atazir could have gameChars partitioned between enemy and the rest, then have the enemy partition sorted by strength, and last find the first enemy in range: the costly operation is performed on the least number of elements.
  $endgroup$
  – papagaga
  44 mins ago
  

  
  
  
  

add a comment | 

2

$begingroup$

The tests c.HP > 0 and c.Team != Team are probably blazingly fast tests. Location.Dist(c.GetLocation()) <= AttackRange probably involves the square-root of the sum of the squares of the difference of coordinates in two or three dimensions. Plus, GetLocation() may involve memory allocation and/or copying constructors. It is by far the slowest test, yet you are testing it first! Take advantage of the short-circuit logical and operators by reordering the tests so the fastest tests are done first, so the slowest test may not even need to be executed, resulting in faster execution.

Bonus: the square-root can be avoided; simply compute the square distance, and compare against the $AttackRange^2$ (computed outside of the loop) for another speed gain.

share|improve this answer

answered 1 hour ago

AJNeufeldAJNeufeld

7,0541723

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I believe you're on the right track but could expand and systematize your answer: for instance, @Atazir could have gameChars partitioned between enemy and the rest, then have the enemy partition sorted by strength, and last find the first enemy in range: the costly operation is performed on the least number of elements.
  $endgroup$
  – papagaga
  44 mins ago
  

  
  
  
  

add a comment | 

$begingroup$

The tests c.HP > 0 and c.Team != Team are probably blazingly fast tests. Location.Dist(c.GetLocation()) <= AttackRange probably involves the square-root of the sum of the squares of the difference of coordinates in two or three dimensions. Plus, GetLocation() may involve memory allocation and/or copying constructors. It is by far the slowest test, yet you are testing it first! Take advantage of the short-circuit logical and operators by reordering the tests so the fastest tests are done first, so the slowest test may not even need to be executed, resulting in faster execution.

Bonus: the square-root can be avoided; simply compute the square distance, and compare against the $AttackRange^2$ (computed outside of the loop) for another speed gain.

share|improve this answer

answered 1 hour ago

AJNeufeldAJNeufeld

7,0541723

$endgroup$

share|improve this answer

answered 1 hour ago

AJNeufeldAJNeufeld

7,0541723

answered 1 hour ago

AJNeufeldAJNeufeld

7,0541723

answered 1 hour ago

AJNeufeldAJNeufeld

7,0541723