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root/radiance/ray/src/rt/data.c
Revision: 2.41
Committed: Thu Mar 14 06:30:53 2024 UTC (2 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: HEAD
Changes since 2.40: +7 -7 lines
Log Message:
perf: Another minor efficieincy tweak

File Contents

# User Rev Content
1 greg 1.1 #ifndef lint
2 greg 2.41 static const char RCSid[] = "$Id: data.c,v 2.40 2024/03/13 07:24:53 greg Exp $";
3 greg 1.1 #endif
4     /*
5     * data.c - routines dealing with interpolated data.
6     */
7    
8 greg 2.16 #include "copyright.h"
9 greg 2.22
10     #include <time.h>
11 greg 2.15
12 greg 2.25 #include "platform.h"
13 schorsch 2.28 #include "paths.h"
14 greg 1.1 #include "standard.h"
15     #include "color.h"
16 greg 1.11 #include "resolu.h"
17 schorsch 2.27 #include "view.h"
18 greg 1.1 #include "data.h"
19    
20 greg 2.7 /* picture memory usage before warning */
21     #ifndef PSIZWARN
22 greg 2.18 #ifdef SMLMEM
23 greg 2.29 #define PSIZWARN 3000000
24 greg 2.18 #else
25 greg 2.34 #define PSIZWARN 50000000
26 greg 2.7 #endif
27     #endif
28 greg 1.1
29 greg 2.7 #ifndef TABSIZ
30 greg 2.35 #define TABSIZ 997 /* table size (prime) */
31 greg 2.7 #endif
32 greg 2.6
33     #define hash(s) (shash(s)%TABSIZ)
34    
35    
36     static DATARRAY *dtab[TABSIZ]; /* data array list */
37 greg 1.1
38 schorsch 2.26 static gethfunc headaspect;
39    
40 greg 1.1
41 greg 2.31 DATARRAY *
42 schorsch 2.27 getdata( /* get data array dname */
43     char *dname
44     )
45 greg 1.1 {
46     char *dfname;
47     FILE *fp;
48 greg 2.30 int asize=0;
49 greg 2.31 int i, j;
50     DATARRAY *dp;
51 greg 1.1 /* look for array in list */
52 greg 2.6 for (dp = dtab[hash(dname)]; dp != NULL; dp = dp->next)
53 greg 1.1 if (!strcmp(dname, dp->name))
54     return(dp); /* found! */
55     /*
56     * If we haven't loaded the data already, we will look
57 greg 2.5 * for it in the directories specified by the library path.
58 greg 1.1 *
59     * The file has the following format:
60     *
61 greg 1.4 * N
62 greg 1.1 * beg0 end0 n0
63     * beg1 end1 n1
64     * . . .
65 greg 1.4 * begN endN nN
66 greg 1.1 * data, later dimensions changing faster
67     * . . .
68     *
69 greg 1.4 * For irregularly spaced points, the following can be
70     * substituted for begi endi ni:
71     *
72 greg 1.6 * 0 0 ni p0i p1i .. pni
73 greg 1.1 */
74    
75 greg 2.17 if ((dfname = getpath(dname, getrlibpath(), R_OK)) == NULL) {
76 greg 1.1 sprintf(errmsg, "cannot find data file \"%s\"", dname);
77 greg 2.32 error(SYSTEM, errmsg);
78 greg 1.1 }
79     if ((fp = fopen(dfname, "r")) == NULL) {
80     sprintf(errmsg, "cannot open data file \"%s\"", dfname);
81     error(SYSTEM, errmsg);
82     }
83     /* get dimensions */
84 greg 2.36 if (fgetval(fp, 'i', &asize) <= 0)
85 greg 1.1 goto scanerr;
86 schorsch 2.24 if ((asize <= 0) | (asize > MAXDDIM)) {
87 greg 1.1 sprintf(errmsg, "bad number of dimensions for \"%s\"", dname);
88     error(USER, errmsg);
89     }
90 greg 2.12 if ((dp = (DATARRAY *)malloc(sizeof(DATARRAY))) == NULL)
91     goto memerr;
92     dp->name = savestr(dname);
93     dp->type = DATATY;
94     dp->nd = asize;
95 greg 1.1 asize = 1;
96     for (i = 0; i < dp->nd; i++) {
97 greg 2.36 if (fgetval(fp, DATATY, &dp->dim[i].org) <= 0)
98 greg 1.6 goto scanerr;
99 greg 2.36 if (fgetval(fp, DATATY, &dp->dim[i].siz) <= 0)
100 greg 1.10 goto scanerr;
101 greg 2.36 if (fgetval(fp, 'i', &dp->dim[i].ne) <= 0)
102 greg 1.10 goto scanerr;
103 greg 1.6 if (dp->dim[i].ne < 2)
104     goto scanerr;
105     asize *= dp->dim[i].ne;
106     if ((dp->dim[i].siz -= dp->dim[i].org) == 0) {
107 greg 2.12 dp->dim[i].p = (DATATYPE *)
108     malloc(dp->dim[i].ne*sizeof(DATATYPE));
109 greg 1.4 if (dp->dim[i].p == NULL)
110     goto memerr;
111 greg 2.10 for (j = 0; j < dp->dim[i].ne; j++)
112 greg 2.36 if (fgetval(fp, DATATY, &dp->dim[i].p[j]) <= 0)
113 greg 1.4 goto scanerr;
114     for (j = 1; j < dp->dim[i].ne-1; j++)
115     if ((dp->dim[i].p[j-1] < dp->dim[i].p[j]) !=
116     (dp->dim[i].p[j] < dp->dim[i].p[j+1]))
117     goto scanerr;
118     dp->dim[i].org = dp->dim[i].p[0];
119     dp->dim[i].siz = dp->dim[i].p[dp->dim[i].ne-1]
120     - dp->dim[i].p[0];
121     } else
122 greg 1.6 dp->dim[i].p = NULL;
123 greg 1.1 }
124 greg 2.12 if ((dp->arr.d = (DATATYPE *)malloc(asize*sizeof(DATATYPE))) == NULL)
125 greg 1.1 goto memerr;
126    
127 greg 2.10 for (i = 0; i < asize; i++)
128 greg 2.36 if (fgetval(fp, DATATY, &dp->arr.d[i]) <= 0)
129 greg 1.1 goto scanerr;
130     fclose(fp);
131 greg 2.6 i = hash(dname);
132     dp->next = dtab[i];
133     return(dtab[i] = dp);
134 greg 1.1 memerr:
135     error(SYSTEM, "out of memory in getdata");
136     scanerr:
137     sprintf(errmsg, "%s in data file \"%s\"",
138     feof(fp) ? "unexpected EOF" : "bad format", dfname);
139     error(USER, errmsg);
140 greg 2.36 return NULL; /* pro forma return */
141 greg 1.1 }
142    
143    
144 greg 2.15 static int
145 schorsch 2.26 headaspect( /* check string for aspect ratio */
146     char *s,
147     void *iap
148     )
149 greg 1.5 {
150 greg 2.33 char fmt[MAXFMTLEN];
151 gwlarson 2.14
152 greg 1.5 if (isaspect(s))
153 schorsch 2.26 *(double*)iap *= aspectval(s);
154 greg 2.36 else if (formatval(fmt, s) && strcmp(fmt, COLRFMT))
155 schorsch 2.26 *(double*)iap = 0.0;
156 gwlarson 2.14 return(0);
157 greg 1.5 }
158    
159 greg 2.31 DATARRAY *
160 schorsch 2.27 getpict( /* get picture pname */
161     char *pname
162     )
163 greg 1.1 {
164 greg 2.4 double inpaspect;
165 greg 1.1 char *pfname;
166     FILE *fp;
167 greg 2.12 COLR *scanin;
168 greg 1.11 int sl, ns;
169 greg 2.3 RESOLU inpres;
170 schorsch 2.21 RREAL loc[2];
171 greg 1.11 int y;
172 greg 2.31 int x, i;
173     DATARRAY *pp;
174 greg 1.1 /* look for array in list */
175 greg 2.12 for (pp = dtab[hash(pname)]; pp != NULL; pp = pp->next)
176 greg 1.1 if (!strcmp(pname, pp->name))
177     return(pp); /* found! */
178    
179 greg 2.17 if ((pfname = getpath(pname, getrlibpath(), R_OK)) == NULL) {
180 greg 1.1 sprintf(errmsg, "cannot find picture file \"%s\"", pname);
181 greg 2.32 error(SYSTEM, errmsg);
182 greg 1.1 }
183 greg 2.12 if ((pp = (DATARRAY *)malloc(3*sizeof(DATARRAY))) == NULL)
184 greg 1.1 goto memerr;
185    
186 greg 2.12 pp[0].name = savestr(pname);
187 greg 1.1
188 greg 2.36 if ((fp = fopen(pfname, "rb")) == NULL) {
189 greg 1.1 sprintf(errmsg, "cannot open picture file \"%s\"", pfname);
190     error(SYSTEM, errmsg);
191     }
192     /* get dimensions */
193 greg 1.5 inpaspect = 1.0;
194 schorsch 2.26 getheader(fp, headaspect, &inpaspect);
195 gwlarson 2.14 if (inpaspect <= FTINY || !fgetsresolu(&inpres, fp))
196 greg 1.1 goto readerr;
197 greg 2.12 pp[0].nd = 2;
198     pp[0].dim[0].ne = inpres.yr;
199     pp[0].dim[1].ne = inpres.xr;
200     pp[0].dim[0].org =
201     pp[0].dim[1].org = 0.0;
202     if (inpres.xr <= inpres.yr*inpaspect) {
203     pp[0].dim[0].siz = inpaspect *
204     (double)inpres.yr/inpres.xr;
205     pp[0].dim[1].siz = 1.0;
206     } else {
207     pp[0].dim[0].siz = 1.0;
208     pp[0].dim[1].siz = (double)inpres.xr/inpres.yr /
209     inpaspect;
210     }
211     pp[0].dim[0].p = pp[0].dim[1].p = NULL;
212     sl = scanlen(&inpres); /* allocate array */
213     ns = numscans(&inpres);
214     i = ns*sl*sizeof(COLR);
215 greg 2.7 #if PSIZWARN
216 greg 2.12 if (i > PSIZWARN) { /* memory warning */
217 greg 2.29 sprintf(errmsg, "picture file \"%s\" using %.1f MB of memory",
218     pname, i*(1.0/(1024*1024)));
219 greg 2.7 error(WARNING, errmsg);
220     }
221     #endif
222 greg 2.12 if ((pp[0].arr.c = (COLR *)malloc(i)) == NULL)
223     goto memerr;
224 greg 1.1 /* load picture */
225 greg 2.12 if ((scanin = (COLR *)malloc(sl*sizeof(COLR))) == NULL)
226 greg 1.1 goto memerr;
227 greg 1.11 for (y = 0; y < ns; y++) {
228 greg 2.12 if (freadcolrs(scanin, sl, fp) < 0)
229 greg 1.1 goto readerr;
230 greg 1.11 for (x = 0; x < sl; x++) {
231     pix2loc(loc, &inpres, x, y);
232     i = (int)(loc[1]*inpres.yr)*inpres.xr +
233     (int)(loc[0]*inpres.xr);
234 greg 2.12 copycolr(pp[0].arr.c[i], scanin[x]);
235 greg 1.11 }
236 greg 1.1 }
237 greg 2.36 free(scanin);
238 greg 1.1 fclose(fp);
239 greg 2.6 i = hash(pname);
240 greg 2.12 pp[0].next = dtab[i]; /* link into picture list */
241 schorsch 2.23 pp[1] = pp[0];
242     pp[2] = pp[0];
243 greg 2.12 pp[0].type = RED; /* differentiate RGB records */
244     pp[1].type = GRN;
245     pp[2].type = BLU;
246     return(dtab[i] = pp);
247 greg 1.1 memerr:
248     error(SYSTEM, "out of memory in getpict");
249     readerr:
250     sprintf(errmsg, "bad picture file \"%s\"", pfname);
251     error(USER, errmsg);
252 greg 2.36 return NULL; /* pro forma return */
253     }
254    
255    
256     /* header info type for hyperspectral image */
257     typedef struct {
258     float wlpart[4]; /* wavelength partitions */
259     int nc; /* number of components */
260     double inpaspect; /* pixel aspect ratio */
261     } SPECINFO;
262    
263     static int
264     specheadline( /* get info for spectral image */
265     char *s,
266     void *cdp
267     )
268     {
269     SPECINFO *sip = (SPECINFO *)cdp;
270     char fmt[MAXFMTLEN];
271    
272     if (isaspect(s))
273     sip->inpaspect *= aspectval(s);
274     else if (isncomp(s))
275     sip->nc = ncompval(s);
276     else if (iswlsplit(s))
277     wlsplitval(sip->wlpart, s);
278     else if (formatval(fmt, s) && strcmp(fmt, SPECFMT))
279     return(-1);
280     return(0);
281     }
282    
283     DATARRAY *
284     getspec( /* load hyperspectral image as data */
285     char *sname
286     )
287     {
288     SPECINFO si;
289     char *pfname;
290     FILE *fp;
291     int sl, ns;
292     int y, i;
293     DATARRAY *pp;
294     /* look for array in list */
295     for (pp = dtab[hash(sname)]; pp != NULL; pp = pp->next)
296     if (!strcmp(sname, pp->name))
297     return(pp); /* found! */
298    
299     if ((pfname = getpath(sname, getrlibpath(), R_OK)) == NULL) {
300     sprintf(errmsg, "cannot find hyperspectral image \"%s\"", sname);
301     error(SYSTEM, errmsg);
302     }
303     if ((fp = fopen(pfname, "rb")) == NULL) {
304     sprintf(errmsg, "cannot open hyperspectral image \"%s\"", pfname);
305     error(SYSTEM, errmsg);
306     }
307     si.wlpart[3] = 0;
308     si.nc = 0;
309     si.inpaspect = 1.0;
310     if (getheader(fp, specheadline, &si) < 0 ||
311     (si.nc <= 3) | (si.nc > MAXCSAMP) | (si.wlpart[3] < 1) ||
312     !fscnresolu(&sl, &ns, fp))
313     goto readerr;
314    
315     if ((pp = (DATARRAY *)malloc(sizeof(DATARRAY))) == NULL)
316     goto memerr;
317    
318     pp->name = savestr(sname);
319     pp->type = SPECTY;
320     pp->nd = 3;
321     pp->dim[0].ne = ns;
322     pp->dim[1].ne = sl;
323     pp->dim[0].org =
324     pp->dim[1].org = 0.0;
325     if (sl <= ns*si.inpaspect) {
326     pp->dim[0].siz = si.inpaspect * (double)ns/sl;
327     pp->dim[1].siz = 1.0;
328     } else {
329     pp->dim[0].siz = 1.0;
330     pp->dim[1].siz = (double)sl/ns / si.inpaspect;
331     }
332     pp->dim[2].ne = si.nc;
333     pp->dim[2].siz = si.wlpart[3] - si.wlpart[0];
334     pp->dim[2].org = si.wlpart[0] + 0.5*pp->dim[2].siz/si.nc;
335     pp->dim[2].siz *= (si.nc - 1.0)/si.nc;
336     pp->dim[0].p = pp->dim[1].p = pp->dim[2].p = NULL;
337     i = ns*sl*(si.nc+1);
338     #if PSIZWARN
339     if (i > PSIZWARN) { /* memory warning */
340     sprintf(errmsg, "hyperspectral image \"%s\" using %.1f MB of memory",
341     sname, i*(1.0/(1024*1024)));
342     error(WARNING, errmsg);
343     }
344     #endif
345     if ((pp->arr.s = (uby8 *)malloc(i)) == NULL)
346     goto memerr;
347     for (y = 0; y < ns; y++) /* read each scanline */
348     if (freadscolrs(pp->arr.s + y*sl*(si.nc+1), si.nc, sl, fp) < 0)
349     goto readerr;
350     fclose(fp);
351     i = hash(sname); /* insert in hash table */
352     pp->next = dtab[i];
353     return(dtab[i] = pp);
354     memerr:
355     error(SYSTEM, "out of memory in getspec");
356     readerr:
357     sprintf(errmsg, "bad hyperspectral image \"%s\"", pfname);
358     error(USER, errmsg);
359     return NULL; /* pro forma return */
360 greg 1.1 }
361    
362    
363 greg 2.31 void
364 schorsch 2.27 freedata( /* release data array reference */
365     DATARRAY *dta
366     )
367 greg 1.1 {
368 greg 2.5 DATARRAY head;
369 greg 2.6 int hval, nents;
370 greg 2.31 DATARRAY *dpl, *dp;
371     int i;
372 greg 1.1
373 greg 2.15 if (dta == NULL) { /* free all if NULL */
374 greg 2.6 hval = 0; nents = TABSIZ;
375     } else {
376 greg 2.38 if (dta->next == dta) {
377     free(dta); /* unlisted temp array */
378     return;
379     }
380 greg 2.15 hval = hash(dta->name); nents = 1;
381 greg 2.37 if (!*dta->name) { /* not a data file? */
382     dta->next = dtab[hval];
383     dtab[hval] = dta; /* ...fake position */
384     }
385 greg 2.6 }
386     while (nents--) {
387     head.next = dtab[hval];
388     dpl = &head;
389     while ((dp = dpl->next) != NULL)
390 schorsch 2.24 if ((dta == NULL) | (dta == dp)) {
391 greg 2.6 dpl->next = dp->next;
392 greg 2.36 free(dp->arr.p);
393 greg 2.6 for (i = 0; i < dp->nd; i++)
394     if (dp->dim[i].p != NULL)
395 greg 2.36 free(dp->dim[i].p);
396 greg 2.6 freestr(dp->name);
397 greg 2.36 free(dp);
398 greg 2.6 } else
399     dpl = dp;
400     dtab[hval++] = head.next;
401     }
402 greg 1.1 }
403    
404    
405 greg 2.37 /* internal call to interpolate data value or vector */
406     static double
407     data_interp(DATARRAY *dp, double *pt, double coef, DATATYPE *rvec)
408     {
409     DATARRAY sd;
410     int stride, i;
411     double x, c0, c1, y0, y1;
412 greg 2.40 /* unlikely, but may as well check */
413     if ((-FTINY <= coef) & (coef <= FTINY))
414     return(0.);
415 greg 2.37 /* set up dimensions for recursion */
416     if (dp->nd > 1) {
417     sd.name = dp->name;
418     sd.type = dp->type;
419     sd.nd = dp->nd - 1;
420     memcpy(sd.dim, dp->dim+1, sd.nd*sizeof(struct dadim));
421     stride = sd.dim[i = sd.nd-1].ne + (sd.type==SPECTY);
422     while (i-- > 0)
423     stride *= sd.dim[i].ne;
424     }
425     /* get independent variable */
426     if (dp->dim[0].p == NULL) { /* evenly spaced points */
427     x = (pt[0] - dp->dim[0].org)/dp->dim[0].siz;
428     x *= (double)(dp->dim[0].ne - 1);
429     i = x;
430     if (i < 0)
431     i = 0;
432     else if (i > dp->dim[0].ne - 2)
433     i = dp->dim[0].ne - 2;
434     } else { /* unevenly spaced points */
435     int lower, upper;
436 greg 2.41 if (dp->dim[0].siz > 0.) {
437 greg 2.37 lower = 0;
438     upper = dp->dim[0].ne;
439     } else {
440     lower = dp->dim[0].ne;
441     upper = 0;
442     }
443     do {
444     i = (lower + upper) >> 1;
445     if (pt[0] >= dp->dim[0].p[i])
446     lower = i;
447     else
448     upper = i;
449     } while (i != (lower + upper) >> 1);
450    
451     if (i > dp->dim[0].ne - 2)
452     i = dp->dim[0].ne - 2;
453    
454     x = i + (pt[0] - dp->dim[0].p[i]) /
455     (dp->dim[0].p[i+1] - dp->dim[0].p[i]);
456     }
457     /*
458     * Compute interpolation coefficients:
459     * extrapolate as far as one division, then
460     * taper off harmonically to zero.
461     */
462     if (x > i+2) {
463     c0 = 1./(i-1 - x);
464     c1 = -2.*c0;
465     } else if (x < i-1) {
466     c1 = 1./(i - x);
467     c0 = -2.*c1;
468     } else {
469     c0 = i+1 - x;
470     c1 = x - i;
471     }
472     c0 *= coef;
473     c1 *= coef;
474     /* check if vector interp */
475     if ((dp->nd == 2) & (rvec != NULL)) {
476     if (dp->type == DATATY) {
477     sd.arr.d = dp->arr.d + i*stride;
478     for (i = sd.dim[0].ne; i--; )
479     rvec[i] += c0*sd.arr.d[i]
480     + c1*sd.arr.d[i+stride];
481 greg 2.39 } else if (dp->type == SPECTY) {
482 greg 2.37 double f;
483     sd.arr.s = dp->arr.s + i*stride;
484 greg 2.40 if ((sd.arr.s[sd.dim[0].ne] > 0) & ((-FTINY>c0)|(c0>FTINY))) {
485 greg 2.41 f = ldexp(c0, (int)sd.arr.s[sd.dim[0].ne]-(COLXS+8));
486 greg 2.40 for (i = sd.dim[0].ne; i--; )
487 greg 2.41 rvec[i] += f*(sd.arr.s[i] + .5);
488 greg 2.40 }
489 greg 2.37 sd.arr.s += stride;
490 greg 2.40 if ((sd.arr.s[sd.dim[0].ne] > 0) & ((-FTINY>c1)|(c1>FTINY))) {
491 greg 2.41 f = ldexp(c1, (int)sd.arr.s[sd.dim[0].ne]-(COLXS+8));
492 greg 2.40 for (i = sd.dim[0].ne; i--; )
493 greg 2.41 rvec[i] += f*(sd.arr.s[i] + .5);
494 greg 2.40 }
495 greg 2.39 } else {
496     sd.arr.c = dp->arr.c + i*stride;
497     for (i = sd.dim[0].ne; i--; )
498     rvec[i] += c0*colrval(sd.arr.c[i],sd.type)
499     + c1*colrval(sd.arr.c[i+stride],sd.type);
500 greg 2.37 }
501 greg 2.39 return(0.); /* return value ignored */
502 greg 2.37 }
503     /* get dependent variable */
504     if (dp->nd > 1) {
505     if (dp->type == DATATY) {
506     sd.arr.d = dp->arr.d + i*stride;
507     y0 = data_interp(&sd, pt+1, c0, rvec);
508     sd.arr.d += stride;
509     } else if (dp->type == SPECTY) {
510     sd.arr.s = dp->arr.s + i*stride;
511     y0 = data_interp(&sd, pt+1, c0, rvec);
512     sd.arr.s += stride;
513     } else {
514     sd.arr.c = dp->arr.c + i*stride;
515     y0 = data_interp(&sd, pt+1, c0, rvec);
516     sd.arr.c += stride;
517     }
518     y1 = data_interp(&sd, pt+1, c1, rvec);
519     } else { /* end of recursion */
520     if (dp->type == DATATY) {
521     y0 = dp->arr.d[i];
522     y1 = dp->arr.d[i+1];
523     } else if (dp->type == SPECTY) {
524     if (dp->arr.s[dp->dim[0].ne]) {
525 greg 2.40 double f = dp->arr.s[dp->dim[0].ne]
526     ? ldexp(1., -(COLXS+8) +
527     (int)dp->arr.s[dp->dim[0].ne])
528     : 0.;
529     y0 = f*(dp->arr.s[i] + 0.5);
530     y1 = f*(dp->arr.s[i+1] + 0.5);
531 greg 2.37 } else
532 greg 2.41 y0 = y1 = 0.;
533 greg 2.37 } else {
534     y0 = colrval(dp->arr.c[i],dp->type);
535     y1 = colrval(dp->arr.c[i+1],dp->type);
536     }
537     y0 *= c0;
538     y1 *= c1;
539     }
540     return(y0 + y1); /* coefficients already applied */
541     }
542    
543    
544     double
545     datavalue( /* interpolate data value at a point */
546     DATARRAY *dp,
547     double *pt
548     )
549     {
550     return(data_interp(dp, pt, 1., NULL));
551     }
552    
553    
554     /* Interpolate final vector corresponding to last dimension in data array */
555     DATARRAY *
556     datavector(DATARRAY *dp, double *pt)
557     {
558     DATARRAY *newdp;
559    
560     if (dp->nd < 2)
561     error(INTERNAL, "datavector() called with 1-D array");
562     /* create vector array */
563     newdp = (DATARRAY *)malloc(sizeof(DATARRAY) -
564     (MAXDDIM-1)*sizeof(struct dadim) +
565     sizeof(DATATYPE)*dp->dim[dp->nd-1].ne);
566     if (newdp == NULL)
567     error(SYSTEM, "out of memory in datavector");
568 greg 2.38 newdp->next = newdp; /* flags us as temp vector */
569 greg 2.37 newdp->name = dp->name;
570     newdp->type = DATATY;
571     newdp->nd = 1; /* vector data goes here */
572     newdp->dim[0] = dp->dim[dp->nd-1];
573     newdp->arr.d = (DATATYPE *)(newdp->dim + 1);
574     memset(newdp->arr.d, 0, sizeof(DATATYPE)*newdp->dim[0].ne);
575    
576     (void)data_interp(dp, pt, 1., newdp->arr.d);
577    
578     return(newdp); /* will be free'd using free() */
579     }
580