Impulse Physics Wiki

User Tools

Site Tools

Trace:
floating_point_comparison

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision 		Previous revision
floating_point_comparison [2022/04/29 23:45]
max 		floating_point_comparison [2022/04/29 23:54] (current)
max
Line 11: Line 11:
 The default option is a combination of both the absolute and relative methods of epsilon comparison. ((http://www.realtimecollisiondetection.net/pubs/Tolerances/)) The default option is a combination of both the absolute and relative methods of epsilon comparison. ((http://www.realtimecollisiondetection.net/pubs/Tolerances/))
 The second option is simply the computer's default "==" operator. It is not recommended, but it is marginally faster.  The second option is simply the computer's default "==" operator. It is not recommended, but it is marginally faster. 
 +
 +Which method the engine uses can be changed in the source code in the ''IPCommon.h'' file.
  
 ===== The absolute method ===== ===== The absolute method =====
Line 20: Line 22:
 ===== The relative method ===== ===== The relative method =====
  
-The relative method takes the result of the absolute method and multiplies the epsilon by ''x'' or ''y'', depending on which is larger.+The relative method takes the absolute method, but multiplies the epsilon by ''x'' or ''y'', depending on which is larger.
  
 The drawback to this method is that it does not work on small values. The drawback to this method is that it does not work on small values.
Line 28: Line 30:
 Considering the strengths and drawbacks of the two methods above, you can combine the two to overcome these limitations.  Considering the strengths and drawbacks of the two methods above, you can combine the two to overcome these limitations. 
  
-The combined method takes the result of the absolute method and multiplies it by the largest absolute number out of a set of ''1'', ''x'', or ''y''. Very similar to the relative method.+The combined method takes the relative method, but multiplies the epsilon by the largest absolute number out of a set of ''1'', ''x'', or ''y''. Very similar to the relative method.
  
 This method gives us good results, but it is not without its drawbacks since it uses the same epsilon for the relative and the absolute tolerance.  This method gives us good results, but it is not without its drawbacks since it uses the same epsilon for the relative and the absolute tolerance. 
  
 For further reading, please check out [[http://www.realtimecollisiondetection.net/pubs/Tolerances/|Christer Erison's research on this topic.]] For further reading, please check out [[http://www.realtimecollisiondetection.net/pubs/Tolerances/|Christer Erison's research on this topic.]]
floating_point_comparison.1651275909.txt.gz ยท Last modified: 2022/04/29 23:45 by max

Page Tools

Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution 4.0 International
CC Attribution 4.0 International Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki