/usr/share/doc/libsuperlu-dev/tests/MATGEN/dlarnd.c is in libsuperlu3-dev 3.0+20070106-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 92 93 | /* -- translated by f2c (version 19940927).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
doublereal dlarnd_(integer *idist, integer *iseed)
{
/* System generated locals */
doublereal ret_val;
/* Builtin functions */
double log(doublereal), sqrt(doublereal), cos(doublereal);
/* Local variables */
static doublereal t1, t2;
extern doublereal dlaran_(integer *);
/* -- LAPACK auxiliary routine (version 2.0) --
Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
Courant Institute, Argonne National Lab, and Rice University
September 30, 1994
Purpose
=======
DLARND returns a random real number from a uniform or normal
distribution.
Arguments
=========
IDIST (input) INTEGER
Specifies the distribution of the random numbers:
= 1: uniform (0,1)
= 2: uniform (-1,1)
= 3: normal (0,1)
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 calls the auxiliary routine DLARAN to generate a random
real number from a uniform (0,1) distribution. The Box-Muller method
is used to transform numbers from a uniform to a normal distribution.
=====================================================================
Generate a real random number from a uniform (0,1) distribution
Parameter adjustments */
--iseed;
/* Function Body */
t1 = dlaran_(&iseed[1]);
if (*idist == 1) {
/* uniform (0,1) */
ret_val = t1;
} else if (*idist == 2) {
/* uniform (-1,1) */
ret_val = t1 * 2. - 1.;
} else if (*idist == 3) {
/* normal (0,1) */
t2 = dlaran_(&iseed[1]);
ret_val = sqrt(log(t1) * -2.) * cos(t2 *
6.2831853071795864769252867663);
}
return ret_val;
/* End of DLARND */
} /* dlarnd_ */
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