src/common/calfunc.c

#ifndef lint
static const char       RCSid[] = "$Id: calfunc.c,v 2.24 2019/07/24 21:20:28 greg Exp $";
#endif
/*
 *  calfunc.c - routines for calcomp using functions.
 *
 *      If VARIABLE is not set, only library functions
 *  can be accessed.
 *
 *  2/19/03     Eliminated conditional compiles in favor of esupport extern.
 */

#include "copyright.h"

#include  <stdio.h>
#include  <string.h>
#include  <errno.h>
#include  <math.h>

#include  "rterror.h"
#include  "calcomp.h"

                                /* bits in argument flag (better be right!) */
#define  AFLAGSIZ       (8*sizeof(unsigned long))
#define  ALISTSIZ       8       /* maximum saved argument list */

typedef struct activation {
    char  *name;                /* function name */
    struct activation  *prev;   /* previous activation */
    double  *ap;                /* argument list */
    unsigned long  an;          /* computed argument flags */
    EPNODE  *fun;               /* argument function */
}  ACTIVATION;          /* an activation record */

static ACTIVATION  *curact = NULL;

static double  libfunc(char *fname, VARDEF *vp);

#ifndef  MAXLIB
#define  MAXLIB         64      /* maximum number of library functions */
#endif

static double  l_if(char *), l_select(char *);
static double  l_min(char *), l_max(char *);
static double  l_rand(char *);
static double  l_floor(char *), l_ceil(char *);
static double  l_sqrt(char *);
static double  l_sin(char *), l_cos(char *), l_tan(char *);
static double  l_asin(char *), l_acos(char *), l_atan(char *), l_atan2(char *);
static double  l_exp(char *), l_log(char *), l_log10(char *);

                        /* functions must be listed alphabetically */
static LIBR  library[MAXLIB] = {
    { "acos", 1, ':', l_acos },
    { "asin", 1, ':', l_asin },
    { "atan", 1, ':', l_atan },
    { "atan2", 2, ':', l_atan2 },
    { "ceil", 1, ':', l_ceil },
    { "cos", 1, ':', l_cos },
    { "exp", 1, ':', l_exp },
    { "floor", 1, ':', l_floor },
    { "if", 3, ':', l_if },
    { "log", 1, ':', l_log },
    { "log10", 1, ':', l_log10 },
    { "max", 1, ':', l_max },
    { "min", 1, ':', l_min },
    { "rand", 1, ':', l_rand },
    { "select", 1, ':', l_select },
    { "sin", 1, ':', l_sin },
    { "sqrt", 1, ':', l_sqrt },
    { "tan", 1, ':', l_tan },
};

static int  libsize = 18;

#define  resolve(ep)    ((ep)->type==VAR?(ep)->v.ln:argf((ep)->v.chan))


int
fundefined(                     /* return # of req'd arguments for function */
        char  *fname
)
{
    LIBR  *lp;
    VARDEF  *vp;

    if ((vp = varlookup(fname)) != NULL && vp->def != NULL
                && vp->def->v.kid->type == FUNC)
        return(nekids(vp->def->v.kid) - 1);
    lp = vp != NULL ? vp->lib : liblookup(fname);
    if (lp == NULL)
        return(0);
    return(lp->nargs);
}


double
funvalue(                       /* return a function value to the user */
        char  *fname,
        int  n,
        double  *a
)
{
    ACTIVATION  act;
    VARDEF  *vp;
    double  rval;
                                        /* push environment */
    act.name = fname;
    act.prev = curact;
    act.ap = a;
    if (n < AFLAGSIZ)
        act.an = (1L<<n)-1;
    else {
        act.an = ~0;
        if (n > AFLAGSIZ)
            wputs("Excess arguments in funvalue()\n");
    }
    act.fun = NULL;
    curact = &act;

    if ((vp = varlookup(fname)) == NULL || vp->def == NULL
                || vp->def->v.kid->type != FUNC)
        rval = libfunc(fname, vp);
    else
        rval = evalue(vp->def->v.kid->sibling);

    curact = act.prev;                  /* pop environment */
    return(rval);
}


void
funset(                         /* set a library function */
        char  *fname,
        int  nargs,
        int  assign,
        double  (*fptr)(char *)
)
{
    int  oldlibsize = libsize;
    char *cp;
    LIBR  *lp;
                                                /* check for context */
    for (cp = fname; *cp; cp++)
        ;
    if (cp == fname)
        return;
    while (cp[-1] == CNTXMARK) {
        *--cp = '\0';
        if (cp == fname) return;
    }
    if ((lp = liblookup(fname)) == NULL) {      /* insert */
        if (fptr == NULL)
                return;                         /* nothing! */
        if (libsize >= MAXLIB) {
            eputs("Too many library functons!\n");
            quit(1);
        }
        for (lp = &library[libsize]; lp > library; lp--)
            if (strcmp(lp[-1].fname, fname) > 0)
                lp[0] = lp[-1];
            else
                break;
        libsize++;
    }
    if (fptr == NULL) {                         /* delete */
        while (lp < &library[libsize-1]) {
            lp[0] = lp[1];
            lp++;
        }
        libsize--;
    } else {                                    /* or assign */
        lp[0].fname = fname;            /* string must be static! */
        lp[0].nargs = nargs;
        lp[0].atyp = assign;
        lp[0].f = fptr;
    }
    if (libsize != oldlibsize)
        libupdate(fname);                       /* relink library */
}


int
nargum(void)                    /* return number of available arguments */
{
    int  n;

    if (curact == NULL)
        return(0);
    if (curact->fun == NULL) {
        for (n = 0; (1L<<n) & curact->an; n++)
            ;
        return(n);
    }
    return(nekids(curact->fun) - 1);
}


double
argument(int n)                 /* return nth argument for active function */
{
    ACTIVATION  *actp = curact;
    EPNODE  *ep = NULL;
    double  aval;

    if (!n)                                     /* asking for # arguments? */
        return((double)nargum());

    if (!actp | (--n < 0)) {
        eputs("Bad call to argument!\n");
        quit(1);
    }
    if ((n < AFLAGSIZ) & actp->an >> n)         /* already computed? */
        return(actp->ap[n]);

    if (!actp->fun || !(ep = ekid(actp->fun, n+1))) {
        eputs(actp->name);
        eputs(": too few arguments\n");
        quit(1);
    }
    curact = actp->prev;                        /* previous context */
    aval = evalue(ep);                          /* compute argument */
    curact = actp;                              /* put back calling context */
    if (n < ALISTSIZ) {                         /* save value if room */
        actp->ap[n] = aval;
        actp->an |= 1L<<n;
    }
    return(aval);
}


VARDEF *
argf(int n)                     /* return function def for nth argument */
{
    ACTIVATION  *actp;
    EPNODE  *ep;

    for (actp = curact; actp != NULL; actp = actp->prev) {

        if (n <= 0)
            break;

        if (actp->fun == NULL)
            goto badarg;

        if ((ep = ekid(actp->fun, n)) == NULL) {
            eputs(actp->name);
            eputs(": too few arguments\n");
            quit(1);
        }
        if (ep->type == VAR)
            return(ep->v.ln);                   /* found it */

        if (ep->type != ARG)
            goto badarg;

        n = ep->v.chan;                         /* try previous context */
    }
    eputs("Bad call to argf!\n");
    quit(1);

badarg:
    eputs(actp->name);
    eputs(": argument not a function\n");
    quit(1);
        return NULL; /* pro forma return */
}


char *
argfun(int n)                   /* return function name for nth argument */
{
    return(argf(n)->name);
}


double
efunc(EPNODE *ep)                       /* evaluate a function */
{
    ACTIVATION  act;
    double  alist[ALISTSIZ];
    double  rval;
    VARDEF  *dp;
                                        /* push environment */
    dp = resolve(ep->v.kid);
    act.name = dp->name;
    act.prev = curact;
    act.ap = alist;
    act.an = 0;
    act.fun = ep;
    curact = &act;

    if (dp->def == NULL || dp->def->v.kid->type != FUNC)
        rval = libfunc(act.name, dp);
    else
        rval = evalue(dp->def->v.kid->sibling);
    
    curact = act.prev;                  /* pop environment */
    return(rval);
}


LIBR *
liblookup(char *fname)          /* look up a library function */
{
    int  upper, lower;
    int  cm, i;

    lower = 0;
    upper = cm = libsize;

    while ((i = (lower + upper) >> 1) != cm) {
        cm = strcmp(fname, library[i].fname);
        if (cm > 0)
            lower = i;
        else if (cm < 0)
            upper = i;
        else
            return(&library[i]);
        cm = i;
    }
    return(NULL);
}


/*
 *  The following routines are for internal use:
 */


static double
libfunc(                                /* execute library function */
        char  *fname,
        VARDEF  *vp
)
{
    LIBR  *lp;
    double  d;
    int  lasterrno;

    if (vp != NULL)
        lp = vp->lib;
    else
        lp = liblookup(fname);
    if (lp == NULL) {
        eputs(fname);
        eputs(": undefined function\n");
        quit(1);
    }
    lasterrno = errno;
    errno = 0;
    d = (*lp->f)(lp->fname);
#ifdef  isnan
    if (errno == 0) {
        if (isnan(d))
            errno = EDOM;
        else if (isinf(d))
            errno = ERANGE;
    }
#endif
    if (errno == EDOM || errno == ERANGE) {
        wputs(fname);
        if (errno == EDOM)
                wputs(": domain error\n");
        else if (errno == ERANGE)
                wputs(": range error\n");
        else
                wputs(": error in call\n");
        return(0.0);
    }
    errno = lasterrno;
    return(d);
}


/*
 *  Library functions:
 */


static double
l_if(char *nm)          /* if(cond, then, else) conditional expression */
                        /* cond evaluates true if greater than zero */
{
    if (argument(1) > 0.0)
        return(argument(2));
    else
        return(argument(3));
}


static double
l_select(char *nm)      /* return argument #(A1+1) */
{
        int     narg = nargum();
        double  a1 = argument(1);
        int  n = (int)(a1 + .5);

        if (a1 < -.5 || n >= narg) {
                errno = EDOM;
                return(0.0);
        }
        if (!n)         /* asking max index? */
                return(narg-1);
        return(argument(n+1));
}


static double
l_max(char *nm)         /* general maximum function */
{
        int  n = nargum();
        int  i = 1;
        double  vmax = argument(1);

        while (i++ < n) {
                double  v = argument(i);
                if (vmax < v)
                        vmax = v;
        }
        return(vmax);
}


static double
l_min(char *nm)         /* general minimum function */
{
        int  n = nargum();
        int  i = 1;
        double  vmin = argument(1);

        while (i++ < n) {
                double  v = argument(i);
                if (vmin > v)
                        vmin = v;
        }
        return(vmin);
}


static double
l_rand(char *nm)                /* random function between 0 and 1 */
{
    double  x;

    x = argument(1);
    x *= 1.0/(1.0 + x*x) + 2.71828182845904;
    x += .785398163397447 - floor(x);
    x = 1e5 / x;
    return(x - floor(x));
}


static double
l_floor(char *nm)               /* return largest integer not greater than arg1 */
{
    return(floor(argument(1)));
}


static double
l_ceil(char *nm)                /* return smallest integer not less than arg1 */
{
    return(ceil(argument(1)));
}


static double
l_sqrt(char *nm)
{
    return(sqrt(argument(1)));
}


static double
l_sin(char *nm)
{
    return(sin(argument(1)));
}


static double
l_cos(char *nm)
{
    return(cos(argument(1)));
}


static double
l_tan(char *nm)
{
    return(tan(argument(1)));
}


static double
l_asin(char *nm)
{
    return(asin(argument(1)));
}


static double
l_acos(char *nm)
{
    return(acos(argument(1)));
}


static double
l_atan(char *nm)
{
    return(atan(argument(1)));
}


static double
l_atan2(char *nm)
{
    return(atan2(argument(1), argument(2)));
}


static double
l_exp(char *nm)
{
    return(exp(argument(1)));
}


static double
l_log(char *nm)
{
    return(log(argument(1)));
}


static double
l_log10(char *nm)
{
    return(log10(argument(1)));
}
Revision:	2.25
Committed:	Thu Nov 7 23:19:54 2019 UTC (4 years, 6 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad5R3
Changes since 2.24:	+3 -1 lines
Log Message:	Added shortcut (should not affect behavior)
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.25	static const char RCSid[] = "$Id: calfunc.c,v 2.24 2019/07/24 21:20:28 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* calfunc.c - routines for calcomp using functions.
6			*
7	greg	2.8	* If VARIABLE is not set, only library functions
8			* can be accessed.
9			*
10			* 2/19/03 Eliminated conditional compiles in favor of esupport extern.
11			*/
12
13	greg	2.9	#include "copyright.h"
14	greg	1.1
15			#include <stdio.h>
16	schorsch	2.11	#include <string.h>
17	greg	1.1	#include <errno.h>
18	greg	2.5	#include <math.h>
19
20	schorsch	2.12	#include "rterror.h"
21	greg	1.1	#include "calcomp.h"
22
23	greg	1.5	/* bits in argument flag (better be right!) */
24			#define AFLAGSIZ (8*sizeof(unsigned long))
25	greg	2.19	#define ALISTSIZ 8 /* maximum saved argument list */
26	greg	1.1
27			typedef struct activation {
28			char name; / function name */
29			struct activation prev; / previous activation */
30			double ap; / argument list */
31			unsigned long an; /* computed argument flags */
32			EPNODE fun; / argument function */
33			} ACTIVATION; /* an activation record */
34
35			static ACTIVATION *curact = NULL;
36
37	schorsch	2.12	static double libfunc(char fname, VARDEF vp);
38	greg	1.1
39	greg	2.8	#ifndef MAXLIB
40	greg	1.1	#define MAXLIB 64 /* maximum number of library functions */
41	greg	2.8	#endif
42	greg	1.1
43	greg	2.21	static double l_if(char ), l_select(char );
44			static double l_min(char ), l_max(char );
45			static double l_rand(char *);
46	greg	2.13	static double l_floor(char ), l_ceil(char );
47			static double l_sqrt(char *);
48			static double l_sin(char ), l_cos(char ), l_tan(char *);
49			static double l_asin(char ), l_acos(char ), l_atan(char ), l_atan2(char );
50			static double l_exp(char ), l_log(char ), l_log10(char *);
51	greg	1.1
52			/* functions must be listed alphabetically */
53			static LIBR library[MAXLIB] = {
54	greg	1.4	{ "acos", 1, ':', l_acos },
55			{ "asin", 1, ':', l_asin },
56			{ "atan", 1, ':', l_atan },
57			{ "atan2", 2, ':', l_atan2 },
58			{ "ceil", 1, ':', l_ceil },
59			{ "cos", 1, ':', l_cos },
60			{ "exp", 1, ':', l_exp },
61			{ "floor", 1, ':', l_floor },
62			{ "if", 3, ':', l_if },
63			{ "log", 1, ':', l_log },
64			{ "log10", 1, ':', l_log10 },
65	greg	2.21	{ "max", 1, ':', l_max },
66			{ "min", 1, ':', l_min },
67	greg	1.4	{ "rand", 1, ':', l_rand },
68			{ "select", 1, ':', l_select },
69			{ "sin", 1, ':', l_sin },
70			{ "sqrt", 1, ':', l_sqrt },
71			{ "tan", 1, ':', l_tan },
72	greg	1.1	};
73
74	greg	2.22	static int libsize = 18;
75	greg	1.1
76			#define resolve(ep) ((ep)->type==VAR?(ep)->v.ln:argf((ep)->v.chan))
77
78
79			int
80	greg	2.21	fundefined( /* return # of req'd arguments for function */
81	greg	2.16	char *fname
82			)
83	greg	1.1	{
84	greg	2.16	LIBR *lp;
85			VARDEF *vp;
86	greg	1.1
87	greg	2.7	if ((vp = varlookup(fname)) != NULL && vp->def != NULL
88			&& vp->def->v.kid->type == FUNC)
89	greg	1.1	return(nekids(vp->def->v.kid) - 1);
90	greg	2.7	lp = vp != NULL ? vp->lib : liblookup(fname);
91			if (lp == NULL)
92			return(0);
93			return(lp->nargs);
94	greg	1.1	}
95
96
97			double
98	greg	2.16	funvalue( /* return a function value to the user */
99			char *fname,
100			int n,
101			double *a
102			)
103	greg	1.1	{
104			ACTIVATION act;
105	greg	2.16	VARDEF *vp;
106	greg	1.1	double rval;
107			/* push environment */
108			act.name = fname;
109			act.prev = curact;
110			act.ap = a;
111	greg	2.19	if (n < AFLAGSIZ)
112			act.an = (1L<<n)-1;
113			else {
114	greg	1.5	act.an = ~0;
115	greg	2.19	if (n > AFLAGSIZ)
116			wputs("Excess arguments in funvalue()\n");
117			}
118	greg	1.1	act.fun = NULL;
119			curact = &act;
120
121			if ((vp = varlookup(fname)) == NULL \|\| vp->def == NULL
122			\|\| vp->def->v.kid->type != FUNC)
123			rval = libfunc(fname, vp);
124			else
125			rval = evalue(vp->def->v.kid->sibling);
126
127			curact = act.prev; /* pop environment */
128			return(rval);
129			}
130
131
132	greg	2.8	void
133	greg	2.16	funset( /* set a library function */
134			char *fname,
135			int nargs,
136			int assign,
137			double (fptr)(char )
138			)
139	greg	1.1	{
140	greg	2.6	int oldlibsize = libsize;
141	greg	2.8	char *cp;
142	greg	2.16	LIBR *lp;
143	greg	2.8	/* check for context */
144			for (cp = fname; *cp; cp++)
145			;
146			if (cp == fname)
147			return;
148	greg	2.21	while (cp[-1] == CNTXMARK) {
149	greg	2.8	*--cp = '\0';
150	greg	2.21	if (cp == fname) return;
151			}
152	greg	2.2	if ((lp = liblookup(fname)) == NULL) { /* insert */
153	greg	2.25	if (fptr == NULL)
154			return; /* nothing! */
155	greg	1.1	if (libsize >= MAXLIB) {
156			eputs("Too many library functons!\n");
157			quit(1);
158			}
159			for (lp = &library[libsize]; lp > library; lp--)
160	greg	2.17	if (strcmp(lp[-1].fname, fname) > 0)
161			lp[0] = lp[-1];
162			else
163	greg	1.1	break;
164			libsize++;
165			}
166	greg	2.2	if (fptr == NULL) { /* delete */
167			while (lp < &library[libsize-1]) {
168	greg	2.17	lp[0] = lp[1];
169	greg	2.2	lp++;
170			}
171			libsize--;
172			} else { /* or assign */
173			lp[0].fname = fname; /* string must be static! */
174			lp[0].nargs = nargs;
175			lp[0].atyp = assign;
176			lp[0].f = fptr;
177			}
178	greg	2.6	if (libsize != oldlibsize)
179			libupdate(fname); /* relink library */
180	greg	1.1	}
181
182
183			int
184	greg	2.16	nargum(void) /* return number of available arguments */
185	greg	1.1	{
186	greg	2.16	int n;
187	greg	1.1
188			if (curact == NULL)
189			return(0);
190			if (curact->fun == NULL) {
191			for (n = 0; (1L<<n) & curact->an; n++)
192			;
193			return(n);
194			}
195			return(nekids(curact->fun) - 1);
196			}
197
198
199			double
200	greg	2.16	argument(int n) /* return nth argument for active function */
201	greg	1.1	{
202	greg	2.16	ACTIVATION *actp = curact;
203			EPNODE *ep = NULL;
204	greg	1.1	double aval;
205
206	greg	2.21	if (!n) /* asking for # arguments? */
207			return((double)nargum());
208
209	greg	2.19	if (!actp \| (--n < 0)) {
210	greg	1.1	eputs("Bad call to argument!\n");
211			quit(1);
212			}
213	greg	2.20	if ((n < AFLAGSIZ) & actp->an >> n) /* already computed? */
214	greg	1.1	return(actp->ap[n]);
215
216	greg	2.19	if (!actp->fun \|\| !(ep = ekid(actp->fun, n+1))) {
217	greg	1.1	eputs(actp->name);
218			eputs(": too few arguments\n");
219			quit(1);
220			}
221	greg	2.19	curact = actp->prev; /* previous context */
222	greg	1.1	aval = evalue(ep); /* compute argument */
223	greg	2.20	curact = actp; /* put back calling context */
224			if (n < ALISTSIZ) { /* save value if room */
225	greg	1.1	actp->ap[n] = aval;
226			actp->an \|= 1L<<n;
227			}
228			return(aval);
229			}
230
231
232			VARDEF *
233	greg	2.16	argf(int n) /* return function def for nth argument */
234	greg	1.1	{
235	greg	2.16	ACTIVATION *actp;
236			EPNODE *ep;
237	greg	1.1
238			for (actp = curact; actp != NULL; actp = actp->prev) {
239
240			if (n <= 0)
241			break;
242
243			if (actp->fun == NULL)
244			goto badarg;
245
246			if ((ep = ekid(actp->fun, n)) == NULL) {
247			eputs(actp->name);
248			eputs(": too few arguments\n");
249			quit(1);
250			}
251			if (ep->type == VAR)
252			return(ep->v.ln); /* found it */
253
254			if (ep->type != ARG)
255			goto badarg;
256
257			n = ep->v.chan; /* try previous context */
258			}
259			eputs("Bad call to argf!\n");
260			quit(1);
261
262			badarg:
263			eputs(actp->name);
264			eputs(": argument not a function\n");
265			quit(1);
266	schorsch	2.11	return NULL; /* pro forma return */
267	greg	1.1	}
268
269
270			char *
271	greg	2.16	argfun(int n) /* return function name for nth argument */
272	greg	1.1	{
273			return(argf(n)->name);
274			}
275
276
277			double
278	greg	2.16	efunc(EPNODE ep) / evaluate a function */
279	greg	1.1	{
280			ACTIVATION act;
281			double alist[ALISTSIZ];
282			double rval;
283	greg	2.16	VARDEF *dp;
284	greg	1.1	/* push environment */
285			dp = resolve(ep->v.kid);
286			act.name = dp->name;
287			act.prev = curact;
288			act.ap = alist;
289			act.an = 0;
290			act.fun = ep;
291			curact = &act;
292
293			if (dp->def == NULL \|\| dp->def->v.kid->type != FUNC)
294			rval = libfunc(act.name, dp);
295			else
296			rval = evalue(dp->def->v.kid->sibling);
297
298			curact = act.prev; /* pop environment */
299			return(rval);
300			}
301
302
303			LIBR *
304	greg	2.16	liblookup(char fname) / look up a library function */
305	greg	1.1	{
306			int upper, lower;
307	greg	2.16	int cm, i;
308	greg	1.1
309			lower = 0;
310			upper = cm = libsize;
311
312			while ((i = (lower + upper) >> 1) != cm) {
313			cm = strcmp(fname, library[i].fname);
314			if (cm > 0)
315			lower = i;
316			else if (cm < 0)
317			upper = i;
318			else
319			return(&library[i]);
320			cm = i;
321			}
322			return(NULL);
323			}
324
325
326			/*
327			* The following routines are for internal use:
328			*/
329
330
331			static double
332	greg	2.16	libfunc( /* execute library function */
333			char *fname,
334			VARDEF *vp
335			)
336	greg	1.1	{
337	greg	2.16	LIBR *lp;
338	greg	1.1	double d;
339			int lasterrno;
340
341	greg	2.3	if (vp != NULL)
342			lp = vp->lib;
343			else
344			lp = liblookup(fname);
345			if (lp == NULL) {
346	greg	1.1	eputs(fname);
347			eputs(": undefined function\n");
348			quit(1);
349			}
350			lasterrno = errno;
351			errno = 0;
352	greg	2.3	d = (*lp->f)(lp->fname);
353	greg	2.15	#ifdef isnan
354	greg	2.18	if (errno == 0) {
355	greg	1.9	if (isnan(d))
356			errno = EDOM;
357			else if (isinf(d))
358			errno = ERANGE;
359	greg	2.18	}
360	greg	1.1	#endif
361	greg	2.10	if (errno == EDOM \|\| errno == ERANGE) {
362	greg	1.1	wputs(fname);
363	greg	1.8	if (errno == EDOM)
364			wputs(": domain error\n");
365			else if (errno == ERANGE)
366			wputs(": range error\n");
367			else
368			wputs(": error in call\n");
369	greg	1.1	return(0.0);
370			}
371			errno = lasterrno;
372			return(d);
373			}
374
375
376			/*
377			* Library functions:
378			*/
379
380
381			static double
382	greg	2.13	l_if(char nm) / if(cond, then, else) conditional expression */
383	greg	1.1	/* cond evaluates true if greater than zero */
384			{
385			if (argument(1) > 0.0)
386			return(argument(2));
387			else
388			return(argument(3));
389			}
390
391
392			static double
393	greg	2.13	l_select(char nm) / return argument #(A1+1) */
394	greg	1.1	{
395	greg	2.23	int narg = nargum();
396			double a1 = argument(1);
397			int n = (int)(a1 + .5);
398	greg	1.1
399	greg	2.23	if (a1 < -.5 \|\| n >= narg) {
400	greg	1.1	errno = EDOM;
401			return(0.0);
402			}
403	greg	2.23	if (!n) /* asking max index? */
404			return(narg-1);
405	greg	1.1	return(argument(n+1));
406			}
407
408
409			static double
410	greg	2.21	l_max(char nm) / general maximum function */
411			{
412			int n = nargum();
413			int i = 1;
414	greg	2.24	double vmax = argument(1);
415	greg	2.21
416			while (i++ < n) {
417			double v = argument(i);
418			if (vmax < v)
419			vmax = v;
420			}
421			return(vmax);
422			}
423
424
425			static double
426			l_min(char nm) / general minimum function */
427			{
428			int n = nargum();
429			int i = 1;
430	greg	2.24	double vmin = argument(1);
431	greg	2.21
432			while (i++ < n) {
433			double v = argument(i);
434			if (vmin > v)
435			vmin = v;
436			}
437			return(vmin);
438			}
439
440
441			static double
442	greg	2.13	l_rand(char nm) / random function between 0 and 1 */
443	greg	1.1	{
444			double x;
445
446			x = argument(1);
447			x = 1.0/(1.0 + xx) + 2.71828182845904;
448			x += .785398163397447 - floor(x);
449			x = 1e5 / x;
450			return(x - floor(x));
451			}
452
453
454			static double
455	greg	2.13	l_floor(char nm) / return largest integer not greater than arg1 */
456	greg	1.1	{
457			return(floor(argument(1)));
458			}
459
460
461			static double
462	greg	2.13	l_ceil(char nm) / return smallest integer not less than arg1 */
463	greg	1.1	{
464			return(ceil(argument(1)));
465			}
466
467
468			static double
469	greg	2.13	l_sqrt(char *nm)
470	greg	1.1	{
471			return(sqrt(argument(1)));
472			}
473
474
475			static double
476	greg	2.13	l_sin(char *nm)
477	greg	1.1	{
478			return(sin(argument(1)));
479			}
480
481
482			static double
483	greg	2.13	l_cos(char *nm)
484	greg	1.1	{
485			return(cos(argument(1)));
486			}
487
488
489			static double
490	greg	2.13	l_tan(char *nm)
491	greg	1.1	{
492			return(tan(argument(1)));
493			}
494
495
496			static double
497	greg	2.13	l_asin(char *nm)
498	greg	1.1	{
499			return(asin(argument(1)));
500			}
501
502
503			static double
504	greg	2.13	l_acos(char *nm)
505	greg	1.1	{
506			return(acos(argument(1)));
507			}
508
509
510			static double
511	greg	2.13	l_atan(char *nm)
512	greg	1.1	{
513			return(atan(argument(1)));
514			}
515
516
517			static double
518	greg	2.13	l_atan2(char *nm)
519	greg	1.1	{
520			return(atan2(argument(1), argument(2)));
521			}
522
523
524			static double
525	greg	2.13	l_exp(char *nm)
526	greg	1.1	{
527			return(exp(argument(1)));
528			}
529
530
531			static double
532	greg	2.13	l_log(char *nm)
533	greg	1.1	{
534			return(log(argument(1)));
535			}
536
537
538			static double
539	greg	2.13	l_log10(char *nm)
540	greg	1.1	{
541			return(log10(argument(1)));
542			}