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1 /***********************************************************
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2 Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The
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3 Netherlands.
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4
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5 All Rights Reserved
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6
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7 Permission to use, copy, modify, and distribute this software and its
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8 documentation for any purpose and without fee is hereby granted,
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9 provided that the above copyright notice appear in all copies and that
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10 both that copyright notice and this permission notice appear in
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11 supporting documentation, and that the names of Stichting Mathematisch
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12 Centrum or CWI not be used in advertising or publicity pertaining to
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13 distribution of the software without specific, written prior permission.
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14
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15 STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
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16 THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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17 FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
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18 FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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19 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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20 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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21 OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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22
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23 ******************************************************************/
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24
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6
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25 /* Portable fmod(x, y) implementation for systems that don't have it */
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26
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27 #include <math.h>
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28 #include <errno.h>
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29
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30 extern int errno;
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31
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32 double
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33 fmod(x, y)
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34 double x, y;
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35 {
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36 double i, f;
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37
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38 if (y == 0.0) {
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39 errno = EDOM;
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40 return 0.0;
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41 }
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42
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43 /* return f such that x = i*y + f for some integer i
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44 such that |f| < |y| and f has the same sign as x */
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45
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46 i = floor(x/y);
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47 f = x - i*y;
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48 if ((x < 0.0) != (y < 0.0))
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49 f = f-y;
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50 return f;
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51 }
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