IfcSameValidPrecision

Semantic definitions at the function

Function Definition

The function compares the epsilon values (given as Precision at IfcGeometricRepresentationContext and ensures that they are the same (with a derivation tolerance) and within reasonable min and max values.

NOTE In the above function the following three questionable ad-hoc values are used:

0.000001 for the default precision (1E-6)

1.001 for the allowable deviation of the precision values and

0.1 for setting the upper limit of the accepted precision values to about 0.1.

HISTORY New function in IFC2x2

Formal representations

EXPRESS Specification

FUNCTION IfcSameValidPrecision
   (Epsilon1, Epsilon2 : REAL) : LOGICAL ;
  LOCAL
    ValidEps1, ValidEps2 : REAL;
    DefaultEps           : REAL := 0.000001;
    DerivationOfEps      : REAL := 1.001;
    UpperEps             : REAL := 1.0;
  END_LOCAL;

    ValidEps1 := NVL(Epsilon1, DefaultEps);
    ValidEps2 := NVL(Epsilon2, DefaultEps);
    RETURN ((0.0 < ValidEps1) AND (ValidEps1 <= (DerivationOfEps * ValidEps2)) AND
            (ValidEps2 <= (DerivationOfEps * ValidEps1)) AND (ValidEps2 < UpperEps));

END_FUNCTION;