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Re: ran intrinsic bug?
- From: Jerry DeLisle <jvdelisle at verizon dot net>
- To: Jerry DeLisle <jvdelisle at verizon dot net>, Fortran List <fortran at gcc dot gnu dot org>
- Date: Sat, 26 Feb 2005 13:32:00 -0800
- Subject: Re: ran intrinsic bug?
- References: <4220DCFA.9040403@verizon.net>
Jerry DeLisle wrote:
Is this a new bug? Compiles and runs with no error with g77.
[jerry@quantum bench]$ f95 -c bug1000.f
In file bug1000.f:12
a(i,j) = ran(init) - .5
1
Error: 'i' argument of 'ran' intrinsic at (1) must be a scalar
My apologies. ran is defined in the program I extracted this from which
is 1000d.f found at netlib. It is defined (see below) and so is not
an intrinsic, but the error message implies that it is.
DOUBLE PRECISION FUNCTION RAN( ISEED )
*
* modified from the LAPACK auxiliary routine 10/12/92 JD
* -- LAPACK auxiliary routine (version 1.0) --
* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
* Courant Institute, Argonne National Lab, and Rice University
* February 29, 1992
*
* .. Array Arguments ..
INTEGER ISEED( 4 )
* ..
*
* Purpose
* =======
*
* DLARAN returns a random real number from a uniform (0,1)
* distribution.
*
* Arguments
* =========
*
* ISEED (input/output) INTEGER array, dimension (4)
* On entry, the seed of the random number generator; the array
* elements must be between 0 and 4095, and ISEED(4) must be
* odd.
* On exit, the seed is updated.
*
* Further Details
* ===============
*
* This routine uses a multiplicative congruential method with modulus
* 2**48 and multiplier 33952834046453 (see G.S.Fishman,
* 'Multiplicative congruential random number generators with modulus
* 2**b: an exhaustive analysis for b = 32 and a partial analysis for
* b = 48', Math. Comp. 189, pp 331-344, 1990).
*
* 48-bit integers are stored in 4 integer array elements with 12 bits
* per element. Hence the routine is portable across machines with
* integers of 32 bits or more.
*
* .. Parameters ..
INTEGER M1, M2, M3, M4
PARAMETER ( M1 = 494, M2 = 322, M3 = 2508, M4 = 2549 )
DOUBLE PRECISION ONE
PARAMETER ( ONE = 1.0D+0 )
INTEGER IPW2
DOUBLE PRECISION R
PARAMETER ( IPW2 = 4096, R = ONE / IPW2 )
* ..
* .. Local Scalars ..
INTEGER IT1, IT2, IT3, IT4
* ..
* .. Intrinsic Functions ..
INTRINSIC DBLE, MOD
* ..
* .. Executable Statements ..
*
* multiply the seed by the multiplier modulo 2**48
*
IT4 = ISEED( 4 )*M4
IT3 = IT4 / IPW2
IT4 = IT4 - IPW2*IT3
IT3 = IT3 + ISEED( 3 )*M4 + ISEED( 4 )*M3
IT2 = IT3 / IPW2
IT3 = IT3 - IPW2*IT2
IT2 = IT2 + ISEED( 2 )*M4 + ISEED( 3 )*M3 + ISEED( 4 )*M2
IT1 = IT2 / IPW2
IT2 = IT2 - IPW2*IT1
IT1 = IT1 + ISEED( 1 )*M4 + ISEED( 2 )*M3 + ISEED( 3 )*M2 +
$ ISEED( 4 )*M1
IT1 = MOD( IT1, IPW2 )
*
* return updated seed
*
ISEED( 1 ) = IT1
ISEED( 2 ) = IT2
ISEED( 3 ) = IT3
ISEED( 4 ) = IT4
*
* convert 48-bit integer to a real number in the interval (0,1)
*
RAN = R*( DBLE( IT1 )+R*( DBLE( IT2 )+R*( DBLE( IT3 )+R*
$ ( DBLE( IT4 ) ) ) ) )
RETURN
*
* End of RAN
*
END