[DGD] Damage Weapons and Stuff (Math and Code)

Ben Chambers bjchamb at bellsouth.net
Tue Jun 3 04:36:02 CEST 2003


Doing timing in C++ resulted in the sin/cos version being slightly faster,
but the standard deviation was incorrect...
----- Original Message -----
From: "Ben Chambers" <bjchamb at bellsouth.net>
To: <dgd at list.imaginary.com>
Sent: Monday, June 02, 2003 10:26 PM
Subject: Re: [DGD] Damage Weapons and Stuff (Math and Code)


> yeah, I was looking on line, this version is taken straight from that
> version but doesn't use the calls to cos/sin... which would be slower...
> sin/cos or this version?
>
> ----- Original Message -----
> From: "White, Ben" <ben.white at dsto.defence.gov.au>
> To: <dgd at list.imaginary.com>
> Sent: Monday, June 02, 2003 10:12 PM
> Subject: RE: [DGD] Damage Weapons and Stuff (Math and Code)
>
>
> > From: Ben Chambers [mailto:bjchamb at bellsouth.net]
> > >
> > > http://www.taygeta.com/random/gaussian.html
> > >
> > > The code found there follows:
> > >          float x1, x2, w, y1, y2;
> > >
> > >          do {
> > >                  x1 = 2.0 * ranf() - 1.0;
> > >                  x2 = 2.0 * ranf() - 1.0;
> > >                  w = x1 * x1 + x2 * x2;
> > >          } while ( w >= 1.0 );
> > >
> > >          w = sqrt( (-2.0 * ln( w ) ) / w );
> > >          y1 = x1 * w;
> > >          y2 = x2 * w;
> > >
> > > As the websites explains, ranf is a function to return a
> > > random number in
> > > the range [0, 1].  The problem is the number of calls that
> > > occur to ranf.
> > > There is the potential that a lot of calls would be made.
> > > How would DGD
> > > handle this?  How fast is the random generation function in DGD?
> > >
> >
> > The area of the square in which the number is being uniformly
> > generated is 4 (2 * 2).  The area of the circle in which the
> > numbers are chosen is 3.14159... (pi * r**2).  So you have a
> > better than 75% chance of getting your number first pop.
> > This does the same thing as one version I posted before, only
> > with the looping instead of a cos/sin...
> >
> > Ben.
> >
> > _________________________________________________________________
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> >
>
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