| Subject: | Error in max/min? Error in clipping? |
| Date: | Mon, 01 Jul 2013 23:05:50 +0200 |
| To: | bug-AI-FuzzyInference [...] rt.cpan.org |
| From: | Jürgen Mück <jurgen.muck [...] yahoo.de> |
[Reprint of an email from Febr 27th 2013 to Ala Qumsieh
(aqumsieh@cpan.org) which has not been responded up to now]
Ala,
thank you very much for your AI::FuzzyInference. I found it the best Fuzzy tool on cpan and studied your code.
(Nevertheless I had to implement my own one to fit my special needs (AI::FuzzyEngine) ).
When analyzing your code I found two issues in AI::FuzzyInference::Set I'm not sure whether they are a bug or I'm thinking wrong:
max (or min):
What happens if the curves of $set1 and $set2 cross?
Say (with max):
$set1: [ 0 => 1, # $x0, $y0
1 => 0] # $x1, $y1
$set2: [ 0 => 0,
1 => 1]
The maximum should be
max: [0 => 1,
0.5 => 0.5, # The curves are crossing
1 => 1]
but in your functions max() and min() I didn't find a place which creates new points ($x coordinates).
clip
Clipping is the same as saying
$clipped_set = min( $limit, $set ),
so all crossings between the (horizontal) $limit value and segments of the membership function should create a new $x and $y.
These are my thoughts. Maybe I oversaw some conversion steps of your membership functions only. I hope so, but I did not find any tests to prove it.
Regards
Jurgen
jmueck@cpan.org
Ala,
thank you very much for your AI::FuzzyInference. I found it the best Fuzzy tool on cpan and studied your code.
(Nevertheless I had to implement my own one to fit my special needs (AI::FuzzyEngine) ).
When analyzing your code I found two issues in AI::FuzzyInference::Set I'm not sure whether they are a bug or I'm thinking wrong:
max (or min):
What happens if the curves of $set1 and $set2 cross?
Say (with max):
$set1: [ 0 => 1, # $x0, $y0
1 => 0] # $x1, $y1
$set2: [ 0 => 0,
1 => 1]
The maximum should be
max: [0 => 1,
0.5 => 0.5, # The curves are crossing
1 => 1]
but in your functions max() and min() I didn't find a place which creates new points ($x coordinates).
clip
Clipping is the same as saying
$clipped_set = min( $limit, $set ),
so all crossings between the (horizontal) $limit value and segments of the membership function should create a new $x and $y.
These are my thoughts. Maybe I oversaw some conversion steps of your membership functions only. I hope so, but I did not find any tests to prove it.
Regards
Jurgen
jmueck@cpan.org