/usr/share/doc/libsuperlu-dev/tests/MATGEN/dlaran.c is in libsuperlu3-dev 3.0+20070106-3.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 | /* -- translated by f2c (version 19940927).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
doublereal dlaran_(integer *iseed)
{
/* System generated locals */
doublereal ret_val;
/* Local variables */
static integer it1, it2, it3, it4;
/* -- LAPACK auxiliary routine (version 2.0) --
Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
Courant Institute, Argonne National Lab, and Rice University
February 29, 1992
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.
=====================================================================
multiply the seed by the multiplier modulo 2**48
Parameter adjustments */
--iseed;
/* Function Body */
it4 = iseed[4] * 2549;
it3 = it4 / 4096;
it4 -= it3 << 12;
it3 = it3 + iseed[3] * 2549 + iseed[4] * 2508;
it2 = it3 / 4096;
it3 -= it2 << 12;
it2 = it2 + iseed[2] * 2549 + iseed[3] * 2508 + iseed[4] * 322;
it1 = it2 / 4096;
it2 -= it1 << 12;
it1 = it1 + iseed[1] * 2549 + iseed[2] * 2508 + iseed[3] * 322 + iseed[4]
* 494;
it1 %= 4096;
/* 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) */
ret_val = ((doublereal) it1 + ((doublereal) it2 + ((doublereal) it3 + (
doublereal) it4 * 2.44140625e-4) * 2.44140625e-4) * 2.44140625e-4)
* 2.44140625e-4;
return ret_val;
/* End of DLARAN */
} /* dlaran_ */
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