# Re: Novice question about flair and geometry debugging

From: Ray F. Cowan <rfc_at_slac.stanford.edu>
Date: Mon, 29 Oct 2012 13:48:57 -0700 (PDT)

Hi Mario,

definition of the VOID region were wrong:

> > This is, I think,
> > equivalent to your second suggestion for void below, which I
> > repeat here:
> >
> >> VOID 5 | +void -(+tgtcyl +tgtcone)
> >
> > Let me know if you disagree. Many, many thanks for pointing
> > out my (now obvious!) mistake.
>
>
> I disagree with the latest statement. If you use parentheses, then
> inside the parentheses you just have to write the logics of the
> TARGET region (a union of bodies, in your case).

To be equivalent to

> >> VOID 5 +void -tgtcyl -tgtcone

when using parentheses I would need to say

> >> VOID 5 +void -(+tgtcyl | +tgtcone)

Thank you again!
--Ray

On Sun, 28 Oct 2012, Santana, Mario wrote:

> Hi Ray,
>
> On Oct 28, 2012, at 2:35 PM, Ray F. Cowan wrote:
>
> > Hi Mario,
> >
> > Thanks so much for the pointer to the problem! Now I have a better
> > understanding of what I was requesting on my region cards.
> >
> > For the target, I wanted the union of the two bodies, tgtcyl and tgtcone.
> >
> >> TARGET 5 +tgtcyl +tgtcone
> >
> > which I now interpret as meaing the intersection of tgtcyl and tgtcone, not
> > their union. To get the union of these two bodies I write
> >
> >> TARGET 5 +tgtcyl | +tgtcone
>
> This is correct '|' is the union operator in FLUKA input syntax
>
> > which I interpret as "points in tgtcone OR in tgtcyl".
> > However, regarding the void region, I want the void body minus both the
> > tgtcyl and tgtcone bodies. My original specification
> >
> >> VOID 5 +void -tgtcyl -tgtcone
> >
> > still seems to me to be correct. I interpret this as
> > "void and not tgtcyl and not tgtcone".
>
> Yes, now this is right. The VOID region is inside void body (thus +void)
> minus (==>negation) the target definition.
> If you negate a union 'A OR B', per boolean logics results to
> NOT(A OR B) = NOT(A) AND NOT(B) thus resulting into the definition
> that you write above.
>
>
> > This is, I think,
> > equivalent to your second suggestion for void below, which I
> > repeat here:
> >
> >> VOID 5 | +void -(+tgtcyl +tgtcone)
> >
> > Let me know if you disagree. Many, many thanks for pointing
> > out my (now obvious!) mistake.
>
>
> I disagree with the latest statement. If you use parentheses, then
> inside the parentheses you just have to write the logics of the
> TARGET region (a union of bodies, in your case).
>
>
> >
> > Thank you,
> > --Ray
>
>
> Mario
>
>
Received on Mon Oct 29 2012 - 23:10:57 CET

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