Where ?b is a negative integer,
the error I get on the (abs ?b) call is:
Rete Exception in routine Value::Value while executing defrule
set_abs_et.
Message: not a float type: type = 0 at line 0: ( run ) .
the error I get on the (- ?a ?b) is:
Rete Exception in routine Value::Value while executing defrule
time_between.
Message: not a float type: type = 4 at line 0: ( run ) .
I was hoping I had the syntax wrong.
There is no problem using the "+" operator with negative numbers,
only the "-" and apparently the abs function.
The fact that (+ ?a ?b) where ?b is negative works but that (- ?a ?b)
does not
made me think that it was a bug in Jess.
If I don't use varaibles the minus works i.e. (- 10 -5) gives 15.
Thanks
Christo
Dr. Ernest J. Friedman-Hill wrote:
>
> I think Christo Andonyadis wrote:
> >
> > I'm using Jess 4.1.
> > I get an error when trying to use the "-" operator with negative
> > numbers.
> > Is this a bug?
>
> Hard to say. WHat error do you get?
>
> >
> > To work around this problem, I am trying to use the abs function to
> > convert the negative number to a positive.
> >
> > What is wrong with this rule?
> > (defrule set_abs
> > (number ?num&:(< ?num 0))
> > =>
> > (assert (abs_num (abs ?num)))
> > )
>
> I don't know. Looks fine to me. Does it cause a problem?
>
> Note that some JVMs have faulty versions of the stream tokenization
> classes that older versions of Jess used to use (4.1 counts as older,
> I think.) These faults could cause problems in parsing negative
> numbers and the minus operator. Later versions of Jess work around
> these problems by not using these classes. You could try upgrading
> your JVM if it's an old one.
>
> ---------------------------------------------------------
> Ernest Friedman-Hill
> Distributed Systems Research Phone: (925) 294-2154
> Sandia National Labs FAX: (925) 294-2234
> Org. 8920, MS 9214 [EMAIL PROTECTED]
> PO Box 969 http://herzberg.ca.sandia.gov
> Livermore, CA 94550
>
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