usr/src/usr.bin/f77/libF77/random_.c

/*-
 * Copyright (c) 1980 The Regents of the University of California.
 * All rights reserved.
 *
 * This module is believed to contain source code proprietary to AT&T.
 * Use and redistribution is subject to the Berkeley Software License
 * Agreement and your Software Agreement with AT&T (Western Electric).
 */

#ifndef lint
static char sccsid[] = "@(#)random_.c   5.5 (Berkeley) 4/12/91";
#endif /* not lint */

/*
 * Routines to return random values
 *
 * calling sequence:
 *      double precision d, drandm
 *      i = irandm(iflag)
 *      x = random(iflag)
 *      d = drandm(iflag)
 * where:
 *      If arg is nonzero, generator is restarted and value is returned.
 *      If arg is 0, next value is returned.
 *      Integer values will range from 0 thru 2147483647 (see random(3)).
 *      Real values will range from 0.0 thru 1.0 .
 */

#if     defined(vax) || defined(tahoe) || defined(hp300)
#define RANDMAX         2147483647
#else   vax || tahoe
        UNKNOWN MACHINE!
#endif  vax || tahoe

long irandm_(iarg)
long *iarg;
{
        if (*iarg) srandom((int)*iarg);
        return( random() );
}

float random_(iarg)
long *iarg;
{
        if (*iarg) srandom((int)*iarg);
        return( (float)(random())/(float)RANDMAX );
}

double drandm_(iarg)
long *iarg;
{
        if (*iarg) srandom((int)*iarg);
        return( (double)(random())/(double)RANDMAX );
}