The R Project SVN R

Rev

Rev 42302 | Rev 54737 | Go to most recent revision | Show entire file | Ignore whitespace | Details | Blame | Last modification | View Log | RSS feed

Rev 42302 Rev 42303
Line -... Line 1...
- 
 
 1 
/*
- 
 
 2 
 *  Mathlib : A C Library of Special Functions
- 
 
 3 
 *  Copyright (C) 1998 Ross Ihaka
- 
 
 4 
 *  Copyright (C) 2000-2001, 2005 The R Development Core Team
- 
 
 5 
 *
- 
 
 6 
 *  This program is free software; you can redistribute it and/or modify
- 
 
 7 
 *  it under the terms of the GNU General Public License as published by
- 
 
 8 
 *  the Free Software Foundation; either version 2 of the License, or
- 
 
 9 
 *  (at your option) any later version.
- 
 
 10 
 *
- 
 
 11 
 *  This program is distributed in the hope that it will be useful,
- 
 
 12 
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- 
 
 13 
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- 
 
 14 
 *  GNU General Public License for more details.
- 
 
 15 
 *
- 
 
 16 
 *  You should have received a copy of the GNU General Public License
- 
 
 17 
 *  along with this program; if not, a copy is available at
- 
 
 18 
 *  http://www.r-project.org/Licenses/
- 
 
 19 
 *
- 
 
 20 
 *  SYNOPSIS
- 
 
 21 
 *
- 
 
 22 
 *    #include <Rmath.h>
- 
 
 23 
 *    double fround(double x, double digits);
- 
 
 24 
 *
- 
 
 25 
 *  DESCRIPTION
- 
 
 26 
 *
- 
 
 27 
 *    Rounds "x" to "digits" decimal digits.
- 
 
 28 
 *
- 
 
 29 
 */
- 
 
 30 
 
- 
 
 31 
#include <config.h> /* needed for HAVE_RINT and USE_BUILTIN_RINT */
- 
 
 32 
#include "nmath.h"
- 
 
 33 
 
- 
 
 34 
/* USE_BUILTIN_RINT could also be defined by a configure test */
- 
 
 35 
#ifndef HAVE_RINT
- 
 
 36 
#define USE_BUILTIN_RINT
- 
 
 37 
#endif
- 
 
 38 
 
- 
 
 39 
#ifdef USE_BUILTIN_RINT
- 
 
 40 
#define R_rint private_rint
- 
 
 41 
 
- 
 
 42 
double attribute_hidden private_rint(double x)
- 
 
 43 
{
- 
 
 44 
    double tmp, sgn = 1.0;
- 
 
 45 
    long ltmp;
- 
 
 46 
 
- 
 
 47 
    if (x != x) return x;			/* NaN */
- 
 
 48 
 
- 
 
 49 
    if (x < 0.0) {
- 
 
 50 
	x = -x;
- 
 
 51 
	sgn = -1.0;
- 
 
 52 
    }
- 
 
 53 
 
- 
 
 54 
    if(x < (double) LONG_MAX) { /* in <limits.h> is architecture dependent */
- 
 
 55 
	ltmp = x + 0.5;
- 
 
 56 
	/* implement round to even */
- 
 
 57 
	if(fabs(x + 0.5 - ltmp) < 10*DBL_EPSILON
- 
 
 58 
	   && (ltmp % 2 == 1)) ltmp--;
- 
 
 59 
	tmp = ltmp;
- 
 
 60 
    } else {
- 
 
 61 
	/* ignore round to even: too small a point to bother */
- 
 
 62 
	tmp = floor(x + 0.5);
- 
 
 63 
    }
- 
 
 64 
    return sgn * tmp;
- 
 
 65 
}
- 
 
 66 
#else
- 
 
 67 
#define R_rint rint
- 
 
 68 
#endif
- 
 
 69 
 
- 
 
 70 
double fround(double x, double digits) {
- 
 
 71 
#define MAX_DIGITS DBL_MAX_10_EXP
- 
 
 72 
    /* = 308 (IEEE); was till R 0.99: (DBL_DIG - 1) */
- 
 
 73 
    /* Note that large digits make sense for very small numbers */
- 
 
 74 
    double pow10, sgn, intx;
- 
 
 75 
    int dig;
- 
 
 76 
 
- 
 
 77 
#ifdef IEEE_754
- 
 
 78 
    if (ISNAN(x) || ISNAN(digits))
- 
 
 79 
	return x + digits;
- 
 
 80 
    if(!R_FINITE(x)) return x;
- 
 
 81 
#endif
- 
 
 82 
 
- 
 
 83 
    if (digits > MAX_DIGITS)
- 
 
 84 
	digits = MAX_DIGITS;
- 
 
 85 
    dig = (int)floor(digits + 0.5);
- 
 
 86 
    if(x < 0.) {
- 
 
 87 
	sgn = -1.;
- 
 
 88 
	x = -x;
- 
 
 89 
    } else
- 
 
 90 
	sgn = 1.;
- 
 
 91 
    if (dig == 0) {
- 
 
 92 
	return sgn * R_rint(x);
- 
 
 93 
    } else if (dig > 0) {
- 
 
 94 
        pow10 = R_pow_di(10., dig);
- 
 
 95 
	intx = floor(x);
- 
 
 96 
	return sgn * (intx + R_rint((x-intx) * pow10) / pow10);
- 
 
 97 
    } else {
- 
 
 98 
        pow10 = R_pow_di(10., -dig);
- 
 
 99 
        return sgn * R_rint(x/pow10) * pow10;
- 
 
 100 
    }
- 
 
 101 
}