Assume the inference of two parallel rules represented in a schematic form as:
Rule 1 | : | IF | X is | THEN | Y is | |
Rule 2 | : | IF | X is | THEN | Y is | |
Fact | : | X is | ||||
Conclusion | : | Y is |
The basic idea of this algorithm consists in generating
The parameterized computation is based on the inclusion of in and/or in characterized by two parameters and . This algorithm uses the simple generalized modus ponens for four major cases characterized by four possible binary values of and :
However does not always respect the previous properties, so and are not always binary values and we have defined four new major cases:
The fast parallel generalized modus ponens algorithm called is defined by and his body is:
Begin ¯
\ If and Then ¯ If ( ) Then ¯
If ( ) Then
Else if and Then
If ( ) Then
If ( ) Then
Else if and Then =min( ¯
If ( ) Then
If ( ) Then
Else if and Then =max( ¯
If ( ) Then
If ( ) Then
End |
The principle of this fast parallel algorithm is to select a case with respect to and and compute with as if and are binary values.
If and are not binary value, the algorithm modifies the core and the support of with respect to and which characterize the inclusion of in and/or in . A parameter is equally introduced to compute the final uncertainty of .
Figure 7: Core computation for 2 parallel rules.
In case (a), is computed only from parameters, and there is a possible displacement of if and . This displacement is obtained by projecting onto V, the intersection of the core of and the core of to find the core of as shown in the figure 7. The core of is represented in grey.
Moreover supports are approximated to eliminate scale effect in as shown in figure 8. Supports are cut from the core along the support to eliminate the part of the support under if . Equally supports are averaged to take into account the part of the support under if .
This solution is applied for all the cases (a), (b), (c), (d) and tries to respect the shape of as possible.
Figure 8: Support approximation.
The case (b) is a similar to case (a).
The case (c) modify cores and supports with an extension if .
The case (d) modifies cores and supports as does case (c), with a reduction if .
But if , the fuzzy set cannot be evaluated by ( ) because the extension of the core is not equal for each side of and . So we have introduced two parameters and to take into account this particularity.