This is the mail archive of the fortran@gcc.gnu.org mailing list for the GNU Fortran project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: [gfortran] Implement irand(), rand(), and srand() for G77 compatibility

From: Steve Kargl <sgk at troutmask dot apl dot washington dot edu>
To: Paul Brook <paul at codesourcery dot com>
Cc: fortran at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
Date: Sun, 30 May 2004 16:45:27 -0700
Subject: Re: [gfortran] Implement irand(), rand(), and srand() for G77 compatibility
References: <20040530185518.GA61701@troutmask.apl.washington.edu> <200405302310.20676.paul@codesourcery.com>

On Sun, May 30, 2004 at 11:10:20PM +0100, Paul Brook wrote:
> On Sunday 30 May 2004 19:55, Steve Kargl wrote:
> 
> > GFC_REAL_4 prefix(rand) (GFC_INTEGER_4 *i)
> > {
> >   return (GFC_REAL_4) (prefix(irand)(i) - 1) / (GFC_REAL_4)(GFC_RAND_M1);
> > }
> 
> This returns values in the range [0,1]
> We really need a reliable routine to convert from integer to real.
> 

Nothing like a 3rd followup message.  The original code is okay.

irand(i) returns a value in the range [1,GFC_RAND_M-1].
irand(i) - 1 is in the range [0,GFC_RAND_M-2].  So, the
division above is in the range [0,1).

-- 
Steve

Follow-Ups:
- Re: [gfortran] Implement irand(), rand(), and srand() for G77 compatibility
  - From: Paul Brook

References:
- [gfortran] Implement irand(), rand(), and srand() for G77 compatibility
  - From: Steve Kargl
- Re: [gfortran] Implement irand(), rand(), and srand() for G77 compatibility
  - From: Paul Brook

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]