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root/radiance/ray/src/gen/gendaylit.c
Revision: 2.13
Committed: Wed Aug 14 17:11:43 2013 UTC (10 years, 8 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.12: +2 -1 lines
Log Message:
Inserted math definition macro

File Contents

# Content
1 /* Copyright (c) 1994,2006 *Fraunhofer Institut for Solar Energy Systems
2 * Heidenhofstr. 2, D-79110 Freiburg, Germany
3 * *Agence de l'Environnement et de la Maitrise de l'Energie
4 * Centre de Valbonne, 500 route des Lucioles, 06565 Sophia Antipolis Cedex, France
5 * *BOUYGUES
6 * 1 Avenue Eugene Freyssinet, Saint-Quentin-Yvelines, France
7 */
8
9 #define _USE_MATH_DEFINES
10 #include <stdio.h>
11 #include <string.h>
12 #include <math.h>
13 #include <stdlib.h>
14
15 #include "color.h"
16 #include "sun.h"
17 #include "paths.h"
18
19 #define DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])
20
21 double normsc();
22
23 /*static char *rcsid="$Header: /cvs/radiance/ray/src/gen/gendaylit.c,v 2.12 2013/08/09 16:44:19 greg Exp $";*/
24
25 float coeff_perez[] = {
26 1.3525,-0.2576,-0.2690,-1.4366,-0.7670,0.0007,1.2734,-0.1233,2.8000,0.6004,1.2375,1.000,1.8734,0.6297,
27 0.9738,0.2809,0.0356,-0.1246,-0.5718,0.9938,-1.2219,-0.7730,1.4148,1.1016,-0.2054,0.0367,-3.9128,0.9156,
28 6.9750,0.1774,6.4477,-0.1239,-1.5798,-0.5081,-1.7812,0.1080,0.2624,0.0672,-0.2190,-0.4285,-1.1000,-0.2515,
29 0.8952,0.0156,0.2782,-0.1812,-4.5000,1.1766,24.7219,-13.0812,-37.7000,34.8438,-5.0000,1.5218,3.9229,
30 -2.6204,-0.0156,0.1597,0.4199,-0.5562,-0.5484,-0.6654,-0.2672,0.7117,0.7234,-0.6219,-5.6812,2.6297,
31 33.3389,-18.3000,-62.2500,52.0781,-3.5000,0.0016,1.1477,0.1062,0.4659,-0.3296,-0.0876,-0.0329,-0.6000,
32 -0.3566,-2.5000,2.3250,0.2937,0.0496,-5.6812,1.8415,21.0000,-4.7656,-21.5906,7.2492,-3.5000,-0.1554,
33 1.4062,0.3988,0.0032,0.0766,-0.0656,-0.1294,-1.0156,-0.3670,1.0078,1.4051,0.2875,-0.5328,-3.8500,3.3750,
34 14.0000,-0.9999,-7.1406,7.5469,-3.4000,-0.1078,-1.0750,1.5702,-0.0672,0.4016,0.3017,-0.4844,-1.0000,
35 0.0211,0.5025,-0.5119,-0.3000,0.1922,0.7023,-1.6317,19.0000,-5.0000,1.2438,-1.9094,-4.0000,0.0250,0.3844,
36 0.2656,1.0468,-0.3788,-2.4517,1.4656,-1.0500,0.0289,0.4260,0.3590,-0.3250,0.1156,0.7781,0.0025,31.0625,
37 -14.5000,-46.1148,55.3750,-7.2312,0.4050,13.3500,0.6234,1.5000,-0.6426,1.8564,0.5636};
38
39
40 float defangle_theta[] = {
41 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84, 84,
42 84, 84, 84, 84, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72,
43 72, 72, 72, 72, 72, 72, 72, 72, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60,
44 60, 60, 60, 60, 60, 60, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
45 48, 48, 48, 48, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 24, 24, 24, 24,
46 24, 24, 24, 24, 24, 24, 24, 24, 12, 12, 12, 12, 12, 12, 0};
47
48 float defangle_phi[] = {
49 0, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240, 252, 264,
50 276, 288, 300, 312, 324, 336, 348, 0, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, 180,
51 192, 204, 216, 228, 240, 252, 264, 276, 288, 300, 312, 324, 336, 348, 0, 15, 30, 45, 60, 75, 90, 105,
52 120, 135, 150, 165, 180, 195, 210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 0, 15, 30, 45, 60, 75,
53 90, 105, 120, 135, 150, 165, 180, 195, 210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 0, 20, 40, 60,
54 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 0, 30, 60, 90, 120, 150, 180, 210,
55 240, 270, 300, 330, 0, 60, 120, 180, 240, 300, 0};
56
57
58
59 /* Perez sky parametrization : epsilon and delta calculations from the direct and diffuse irradiances */
60 double sky_brightness();
61 double sky_clearness();
62
63 /* calculation of the direct and diffuse components from the Perez parametrization */
64 double diffuse_irradiance_from_sky_brightness();
65 double direct_irradiance_from_sky_clearness();
66
67 /* Perez global horizontal, diffuse horizontal and direct normal luminous efficacy models : */
68 /* input w(cm)=2cm, solar zenith angle(degrees); output efficacy(lm/W) */
69
70 double glob_h_effi_PEREZ();
71 double glob_h_diffuse_effi_PEREZ();
72 double direct_n_effi_PEREZ();
73
74 /*likelihood check of the epsilon, delta, direct and diffuse components*/
75 void check_parametrization();
76 void check_irradiances();
77 void check_illuminances();
78 void illu_to_irra_index();
79 void print_error_sky();
80
81 double calc_rel_lum_perez(double dzeta,double gamma,double Z,double epsilon,double Delta,float coeff_perez[]);
82 void coeff_lum_perez(double Z, double epsilon, double Delta, float coeff_perez[]);
83 double radians(double degres);
84 double degres(double radians);
85 void theta_phi_to_dzeta_gamma(double theta,double phi,double *dzeta,double *gamma, double Z);
86 double integ_lv(float *lv,float *theta);
87
88 void printdefaults();
89 void check_sun_position();
90 void computesky();
91 void printhead(int ac, char** av);
92 void userror(char* msg);
93 void printsky();
94
95 FILE * frlibopen(char* fname);
96
97 /* astronomy and geometry*/
98 double get_eccentricity();
99 double air_mass();
100
101 double solar_sunset();
102 double solar_sunrise();
103 double stadj();
104 int jdate(int month, int day);
105
106
107
108 /* sun calculation constants */
109 extern double s_latitude;
110 extern double s_longitude;
111 extern double s_meridian;
112
113 const double AU = 149597890E3;
114 const double solar_constant_e = 1367; /* solar constant W/m^2 */
115 const double solar_constant_l = 127.5; /* solar constant klux */
116
117 const double half_sun_angle = 0.2665;
118 const double half_direct_angle = 2.85;
119
120 const double skyclearinf = 1.0; /* limitations for the variation of the Perez parameters */
121 const double skyclearsup = 12.1;
122 const double skybriginf = 0.01;
123 const double skybrigsup = 0.6;
124
125
126
127 /* required values */
128 int month, day; /* date */
129 double hour; /* time */
130 int tsolar; /* 0=standard, 1=solar */
131 double altitude, azimuth; /* or solar angles */
132
133
134
135 /* definition of the sky conditions through the Perez parametrization */
136 double skyclearness = 0;
137 double skybrightness = 0;
138 double solarradiance;
139 double diffuseilluminance, directilluminance, diffuseirradiance, directirradiance, globalirradiance;
140 double sunzenith, daynumber, atm_preci_water=2;
141
142 /*double sunaltitude_border = 0;*/
143 double diffnormalization = 0;
144 double dirnormalization = 0;
145 double *c_perez;
146
147 int output=0; /* define the unit of the output (sky luminance or radiance): */
148 /* visible watt=0, solar watt=1, lumen=2 */
149 int input=0; /* define the input for the calulation */
150
151 int suppress_warnings=0;
152
153 /* default values */
154 int cloudy = 0; /* 1=standard, 2=uniform */
155 int dosun = 1;
156 double zenithbr = -1.0;
157 double betaturbidity = 0.1;
158 double gprefl = 0.2;
159 int S_INTER=0;
160
161 /* computed values */
162 double sundir[3];
163 double groundbr = 0;
164 double F2;
165 double solarbr = 0.0;
166 int u_solar = 0; /* -1=irradiance, 1=radiance */
167 float timeinterval = 0;
168
169 char *progname;
170 char errmsg[128];
171
172
173
174
175 int main(int argc, char** argv)
176 {
177 int i;
178
179 progname = argv[0];
180 if (argc == 2 && !strcmp(argv[1], "-defaults")) {
181 printdefaults();
182 return 0;
183 }
184 if (argc < 4)
185 userror("arg count");
186 if (!strcmp(argv[1], "-ang")) {
187 altitude = atof(argv[2]) * (M_PI/180);
188 azimuth = atof(argv[3]) * (M_PI/180);
189 month = 0;
190 } else {
191 month = atoi(argv[1]);
192 if (month < 1 || month > 12)
193 userror("bad month");
194 day = atoi(argv[2]);
195 if (day < 1 || day > 31)
196 userror("bad day");
197 hour = atof(argv[3]);
198 if (hour < 0 || hour >= 24)
199 userror("bad hour");
200 tsolar = argv[3][0] == '+';
201 }
202 for (i = 4; i < argc; i++)
203 if (argv[i][0] == '-' || argv[i][0] == '+')
204 switch (argv[i][1]) {
205 case 's':
206 cloudy = 0;
207 dosun = argv[i][0] == '+';
208 break;
209 case 'R':
210 u_solar = argv[i][1] == 'R' ? -1 : 1;
211 solarbr = atof(argv[++i]);
212 break;
213 case 'c':
214 cloudy = argv[i][0] == '+' ? 2 : 1;
215 dosun = 0;
216 break;
217 case 't':
218 betaturbidity = atof(argv[++i]);
219 break;
220 case 'w':
221 suppress_warnings = 1;
222 break;
223 case 'b':
224 zenithbr = atof(argv[++i]);
225 break;
226 case 'g':
227 gprefl = atof(argv[++i]);
228 break;
229 case 'a':
230 s_latitude = atof(argv[++i]) * (M_PI/180);
231 break;
232 case 'o':
233 s_longitude = atof(argv[++i]) * (M_PI/180);
234 break;
235 case 'm':
236 s_meridian = atof(argv[++i]) * (M_PI/180);
237 break;
238
239 case 'O':
240 output = atof(argv[++i]); /*define the unit of the output of the program :
241 sky and sun luminance/radiance (0==W visible, 1==W solar radiation, 2==lm) */
242 break;
243
244 case 'P':
245 input = 0; /* Perez parameters: epsilon, delta */
246 skyclearness = atof(argv[++i]);
247 skybrightness = atof(argv[++i]);
248 break;
249
250 case 'W': /* direct normal Irradiance [W/m^2] */
251 input = 1; /* diffuse horizontal Irrad. [W/m^2] */
252 directirradiance = atof(argv[++i]);
253 diffuseirradiance = atof(argv[++i]);
254 break;
255
256 case 'L': /* direct normal Illuminance [Lux] */
257 input = 2; /* diffuse horizontal Ill. [Lux] */
258 directilluminance = atof(argv[++i]);
259 diffuseilluminance = atof(argv[++i]);
260 break;
261
262 case 'G': /* direct horizontal Irradiance [W/m^2] */
263 input = 3; /* diffuse horizontal Irrad. [W/m^2] */
264 directirradiance = atof(argv[++i]);
265 diffuseirradiance = atof(argv[++i]);
266 break;
267
268 case 'E': /* Erbs model based on the */
269 input = 4; /* global-horizontal irradiance [W/m^2] */
270 globalirradiance = atof(argv[++i]);
271 break;
272
273 /*
274 case 'l':
275 sunaltitude_border = atof(argv[++i]);
276 break;
277 */
278
279 case 'i':
280 timeinterval = atof(argv[++i]);
281 break;
282
283
284 default:
285 sprintf(errmsg, "unknown option: %s", argv[i]);
286 userror(errmsg);
287 }
288 else
289 userror("bad option");
290
291 if (fabs(s_meridian-s_longitude) > 30*M_PI/180)
292 fprintf(stderr,
293 "%s: warning: %.1f hours btwn. standard meridian and longitude\n",
294 progname, (s_longitude-s_meridian)*12/M_PI);
295
296
297 /* dynamic memory allocation for the pointers */
298
299 if ( (c_perez = calloc(5, sizeof(double))) == NULL )
300 {
301 fprintf(stderr,"Out of memory error in function main");
302 return 1;
303 }
304
305 printhead(argc, argv);
306 computesky();
307
308 if(*(c_perez+1)>0)
309 {
310 fprintf(stderr, "Warning: positive Perez parameter B (= %lf), printing error sky\n",*(c_perez+1));
311 print_error_sky();
312 exit(1);
313 }
314
315 printsky();
316 return 0;
317 }
318
319
320
321
322
323
324
325
326 void computesky()
327 {
328
329 int j;
330
331 float *lv_mod; /* 145 luminance values */
332 float *theta_o, *phi_o;
333 double dzeta, gamma;
334 double normfactor;
335 double erbs_s0, erbs_kt;
336
337
338 /* compute solar direction */
339
340 if (month) { /* from date and time */
341 int jd;
342 double sd, st;
343
344 jd = jdate(month, day); /* Julian date */
345 sd = sdec(jd); /* solar declination */
346 if (tsolar) /* solar time */
347 st = hour;
348 else
349 st = hour + stadj(jd);
350
351
352 if(st<solar_sunrise(month,day) || st>solar_sunset(month,day)) {
353 print_error_sky();
354 exit(1);
355 }
356
357
358 if(timeinterval) {
359
360 if(timeinterval<0) {
361 fprintf(stderr, "time interval negative\n");
362 exit(1);
363 }
364
365 if(fabs(solar_sunrise(month,day)-st)<timeinterval/60) {
366
367 fprintf(stderr, "Solar position corrected at %d %d %.3f\n",month,day,hour);
368 st= (st+timeinterval/120+solar_sunrise(month,day))/2;
369 }
370
371 if(fabs(solar_sunset(month,day)-st)<timeinterval/60) {
372 fprintf(stderr, "Solar position corrected at %d %d %.3f\n",month,day,hour);
373 st= (st-timeinterval/120+solar_sunset(month,day))/2;
374 }
375 }
376
377
378 altitude = salt(sd, st);
379 azimuth = sazi(sd, st);
380
381 daynumber = (double)jdate(month, day);
382
383 }
384
385
386
387
388 /* if loop for the -l option. W.Sprenger (01/2013) */
389 /*
390 if (altitude*180/M_PI < sunaltitude_border) {
391
392 if (suppress_warnings==0) {
393 fprintf(stderr, "Warning: sun altitude (%.3f degrees) below the border (%.3f degrees)\n",altitude*180/M_PI,sunaltitude_border);
394 }
395 print_error_sky();
396 exit(1);
397 }
398 */
399
400
401 if (!cloudy && altitude > 87.*M_PI/180.) {
402
403 if (suppress_warnings==0) {
404 fprintf(stderr,
405 "%s: warning - sun too close to zenith, reducing altitude to 87 degrees\n",
406 progname);
407 }
408 altitude = 87.*M_PI/180.;
409 }
410
411 sundir[0] = -sin(azimuth)*cos(altitude);
412 sundir[1] = -cos(azimuth)*cos(altitude);
413 sundir[2] = sin(altitude);
414
415
416 /* calculation for the new functions */
417 sunzenith = 90 - altitude*180/M_PI;
418
419
420
421 /* compute the inputs for the calculation of the light distribution over the sky*/
422 if (input==0) /* P */
423 {
424 check_parametrization();
425 diffuseirradiance = diffuse_irradiance_from_sky_brightness(); /*diffuse horizontal irradiance*/
426 directirradiance = direct_irradiance_from_sky_clearness();
427 check_irradiances();
428
429 if (output==0 || output==2)
430 {
431 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
432 directilluminance = directirradiance*direct_n_effi_PEREZ();
433 check_illuminances();
434 }
435 }
436
437
438 else if (input==1) /* W */
439 {
440 check_irradiances();
441 skybrightness = sky_brightness();
442 skyclearness = sky_clearness();
443 check_parametrization();
444
445 if (output==0 || output==2)
446 {
447 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
448 directilluminance = directirradiance*direct_n_effi_PEREZ();
449 check_illuminances();
450 }
451
452 }
453
454
455 else if (input==2) /* L */
456 {
457 check_illuminances();
458 illu_to_irra_index();
459 check_parametrization();
460 }
461
462
463 else if (input==3) /* G */
464 {
465 if (altitude<=0)
466 {
467 if (suppress_warnings==0)
468 fprintf(stderr, "Warning: solar zenith angle larger than 90 degrees; using zero irradiance to proceed\n");
469 directirradiance = 0;
470 diffuseirradiance = 0;
471 } else {
472
473 directirradiance=directirradiance/sin(altitude);
474 }
475
476 check_irradiances();
477 skybrightness = sky_brightness();
478 skyclearness = sky_clearness();
479 check_parametrization();
480
481 if (output==0 || output==2)
482 {
483 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
484 directilluminance = directirradiance*direct_n_effi_PEREZ();
485 check_illuminances();
486 }
487
488 }
489
490
491 else if (input==4) /* E */ /* Implementation of the Erbs model. W.Sprenger (04/13) */
492 {
493
494 if (altitude<=0)
495 {
496 if (suppress_warnings==0 && globalirradiance > 50)
497 fprintf(stderr, "Warning: global irradiance higher than 50 W/m^2 while the sun altitude is lower than zero\n");
498 globalirradiance = 0; diffuseirradiance = 0; directirradiance = 0;
499
500 } else {
501
502 erbs_s0 = solar_constant_e*get_eccentricity()*sin(altitude);
503
504 if (globalirradiance>erbs_s0)
505 {
506 if (suppress_warnings==0)
507 fprintf(stderr, "Warning: global irradiance is higher than the time-dependent solar constant s0\n");
508
509 globalirradiance=erbs_s0*0.999;
510 }
511
512 erbs_kt=globalirradiance/erbs_s0;
513
514 if (erbs_kt<=0.22) diffuseirradiance=globalirradiance*(1-0.09*erbs_kt);
515 else if (erbs_kt<=0.8) diffuseirradiance=globalirradiance*(0.9511-0.1604*erbs_kt+4.388*pow(erbs_kt,2)-16.638*pow(erbs_kt,3)+12.336*pow(erbs_kt,4));
516 else if (erbs_kt<1) diffuseirradiance=globalirradiance*(0.165);
517
518 directirradiance=globalirradiance-diffuseirradiance;
519
520 printf("# erbs_s0, erbs_kt, irr_dir_h, irr_diff: %.3f %.3f %.3f %.3f\n", erbs_s0, erbs_kt, directirradiance, diffuseirradiance);
521 printf("# WARNING: the -E option is only recommended for a rough estimation!");
522
523 directirradiance=directirradiance/sin(altitude);
524
525 }
526
527 check_irradiances();
528 skybrightness = sky_brightness();
529 skyclearness = sky_clearness();
530 check_parametrization();
531
532 if (output==0 || output==2)
533 {
534 diffuseilluminance = diffuseirradiance*glob_h_diffuse_effi_PEREZ();/*diffuse horizontal illuminance*/
535 directilluminance = directirradiance*direct_n_effi_PEREZ();
536 check_illuminances();
537 }
538
539 }
540
541
542
543
544 else {fprintf(stderr,"error at the input arguments"); exit(1);}
545
546
547
548 /* normalization factor for the relative sky luminance distribution, diffuse part*/
549
550 if ( (lv_mod = malloc(145*sizeof(float))) == NULL)
551 {
552 fprintf(stderr,"Out of memory in function main");
553 exit(1);
554 }
555
556 /* read the angles */
557 theta_o = defangle_theta;
558 phi_o = defangle_phi;
559
560
561 /* parameters for the perez model */
562 coeff_lum_perez(radians(sunzenith), skyclearness, skybrightness, coeff_perez);
563
564
565
566
567
568 /*calculation of the modelled luminance */
569 for (j=0;j<145;j++)
570 {
571 theta_phi_to_dzeta_gamma(radians(*(theta_o+j)),radians(*(phi_o+j)),&dzeta,&gamma,radians(sunzenith));
572
573 *(lv_mod+j) = calc_rel_lum_perez(dzeta,gamma,radians(sunzenith),skyclearness,skybrightness,coeff_perez);
574
575 /* fprintf(stderr,"theta, phi, lv_mod %f\t %f\t %f\n", *(theta_o+j),*(phi_o+j),*(lv_mod+j)); */
576 }
577
578 /* integration of luminance for the normalization factor, diffuse part of the sky*/
579
580 diffnormalization = integ_lv(lv_mod, theta_o);
581
582
583
584 /*normalization coefficient in lumen or in watt*/
585 if (output==0)
586 {
587 diffnormalization = diffuseilluminance/diffnormalization/WHTEFFICACY;
588 }
589 else if (output==1)
590 {
591 diffnormalization = diffuseirradiance/diffnormalization;
592 }
593 else if (output==2)
594 {
595 diffnormalization = diffuseilluminance/diffnormalization;
596 }
597
598 else {fprintf(stderr,"Wrong output specification.\n"); exit(1);}
599
600
601
602
603 /* calculation for the solar source */
604 if (output==0)
605 solarradiance = directilluminance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)))/WHTEFFICACY;
606
607 else if (output==1)
608 solarradiance = directirradiance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)));
609
610 else
611 solarradiance = directilluminance/(2*M_PI*(1-cos(half_sun_angle*M_PI/180)));
612
613
614
615
616 /* Compute the ground radiance */
617 zenithbr=calc_rel_lum_perez(0.0,radians(sunzenith),radians(sunzenith),skyclearness,skybrightness,coeff_perez);
618 zenithbr*=diffnormalization;
619
620 if (skyclearness==1)
621 normfactor = 0.777778;
622
623 if (skyclearness>=6)
624 {
625 F2 = 0.274*(0.91 + 10.0*exp(-3.0*(M_PI/2.0-altitude)) + 0.45*sundir[2]*sundir[2]);
626 normfactor = normsc()/F2/M_PI;
627 }
628
629 if ( (skyclearness>1) && (skyclearness<6) )
630 {
631 S_INTER=1;
632 F2 = (2.739 + .9891*sin(.3119+2.6*altitude)) * exp(-(M_PI/2.0-altitude)*(.4441+1.48*altitude));
633 normfactor = normsc()/F2/M_PI;
634 }
635
636 groundbr = zenithbr*normfactor;
637
638 if (dosun&&(skyclearness>1))
639 groundbr += 6.8e-5/M_PI*solarradiance*sundir[2];
640
641 groundbr *= gprefl;
642
643
644
645 return;
646 }
647
648
649
650
651 void print_error_sky()
652 {
653 sundir[0] = -sin(azimuth)*cos(altitude);
654 sundir[1] = -cos(azimuth)*cos(altitude);
655 sundir[2] = sin(altitude);
656
657 printf("\nvoid brightfunc skyfunc\n");
658 printf("2 skybright perezlum.cal\n");
659 printf("0\n");
660 printf("10 0.00 0.00 0.000 0.000 0.000 0.000 0.000 %f %f %f \n", sundir[0], sundir[1], sundir[2]);
661 }
662
663
664
665
666
667
668
669 double solar_sunset(int month,int day)
670 {
671 float W;
672 extern double s_latitude;
673 W=-1*(tan(s_latitude)*tan(sdec(jdate(month, day))));
674 return(12+(M_PI/2 - atan2(W,sqrt(1-W*W)))*180/(M_PI*15));
675 }
676
677
678 double solar_sunrise(int month,int day)
679 {
680 float W;
681 extern double s_latitude;
682 W=-1*(tan(s_latitude)*tan(sdec(jdate(month, day))));
683 return(12-(M_PI/2 - atan2(W,sqrt(1-W*W)))*180/(M_PI*15));
684 }
685
686
687
688
689
690
691
692
693
694
695
696 void printsky() /* print out sky */
697 {
698 if (dosun&&(skyclearness>1))
699 {
700 printf("\nvoid light solar\n");
701 printf("0\n0\n");
702 printf("3 %.3e %.3e %.3e\n", solarradiance, solarradiance, solarradiance);
703 printf("\nsolar source sun\n");
704 printf("0\n0\n");
705 printf("4 %f %f %f %f\n", sundir[0], sundir[1], sundir[2], 2*half_sun_angle);
706 } else if (dosun) {
707 printf("\nvoid light solar\n");
708 printf("0\n0\n");
709 printf("3 0.0 0.0 0.0\n");
710 printf("\nsolar source sun\n");
711 printf("0\n0\n");
712 printf("4 %f %f %f %f\n", sundir[0], sundir[1], sundir[2], 2*half_sun_angle);
713 }
714
715
716 printf("\nvoid brightfunc skyfunc\n");
717 printf("2 skybright perezlum.cal\n");
718 printf("0\n");
719 printf("10 %.3e %.3e %lf %lf %lf %lf %lf %f %f %f \n", diffnormalization, groundbr,
720 *(c_perez+0),*(c_perez+1),*(c_perez+2),*(c_perez+3),*(c_perez+4),
721 sundir[0], sundir[1], sundir[2]);
722
723 }
724
725
726 void printdefaults() /* print default values */
727 {
728 printf("-g %f\t\t\t# Ground plane reflectance\n", gprefl);
729 if (zenithbr > 0.0)
730 printf("-b %f\t\t\t# Zenith radiance (watts/ster/m^2\n", zenithbr);
731 else
732 printf("-t %f\t\t\t# Atmospheric betaturbidity\n", betaturbidity);
733 printf("-a %f\t\t\t# Site latitude (degrees)\n", s_latitude*(180/M_PI));
734 printf("-o %f\t\t\t# Site longitude (degrees)\n", s_longitude*(180/M_PI));
735 printf("-m %f\t\t\t# Standard meridian (degrees)\n", s_meridian*(180/M_PI));
736 }
737
738
739 void userror(char* msg) /* print usage error and quit */
740 {
741 if (msg != NULL)
742 fprintf(stderr, "%s: Use error - %s\n\n", progname, msg);
743 fprintf(stderr, "Usage: %s month day hour [...]\n", progname);
744 fprintf(stderr, " or: %s -ang altitude azimuth [...]\n", progname);
745 fprintf(stderr, " followed by: -P epsilon delta [options]\n");
746 fprintf(stderr, " or: [-W|-L|-G] direct_value diffuse_value [options]\n");
747 fprintf(stderr, " or: -E global_irradiance [options]\n\n");
748 fprintf(stderr, " Description:\n");
749 fprintf(stderr, " -P epsilon delta (these are the Perez parameters) \n");
750 fprintf(stderr, " -W direct-normal-irradiance diffuse-horizontal-irradiance (W/m^2)\n");
751 fprintf(stderr, " -L direct-normal-illuminance diffuse-horizontal-illuminance (lux)\n");
752 fprintf(stderr, " -G direct-horizontal-irradiance diffuse-horizontal-irradiance (W/m^2)\n");
753 fprintf(stderr, " -E global-horizontal-irradiance (W/m^2)\n\n");
754 fprintf(stderr, " Output specification with option:\n");
755 fprintf(stderr, " -O [0|1|2] (0=output in W/m^2/sr visible, 1=output in W/m^2/sr solar, 2=output in candela/m^2), default is 0 \n");
756 fprintf(stderr, " gendaylit version 2.3 (2013/08/08) \n\n");
757 exit(1);
758 }
759
760
761
762 double normsc() /* compute normalization factor (E0*F2/L0) */
763 {
764 static double nfc[2][5] = {
765 /* clear sky approx. */
766 {2.766521, 0.547665, -0.369832, 0.009237, 0.059229},
767 /* intermediate sky approx. */
768 {3.5556, -2.7152, -1.3081, 1.0660, 0.60227},
769 };
770 register double *nf;
771 double x, nsc;
772 register int i;
773 /* polynomial approximation */
774 nf = nfc[S_INTER];
775 x = (altitude - M_PI/4.0)/(M_PI/4.0);
776 nsc = nf[i=4];
777 while (i--)
778 nsc = nsc*x + nf[i];
779
780 return(nsc);
781 }
782
783
784
785 void printhead(int ac, char** av) /* print command header */
786 {
787 putchar('#');
788 while (ac--) {
789 putchar(' ');
790 fputs(*av++, stdout);
791 }
792 putchar('\n');
793 }
794
795
796
797
798 /* Perez models */
799
800 /* Perez global horizontal luminous efficacy model */
801 double glob_h_effi_PEREZ()
802 {
803
804 double value;
805 double category_bounds[10], a[10], b[10], c[10], d[10];
806 int category_total_number, category_number, i;
807
808 check_parametrization();
809
810
811 /*if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
812 fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function glob_h_effi_PEREZ \n"); */
813
814
815 /* initialize category bounds (clearness index bounds) */
816
817 category_total_number = 8;
818
819 category_bounds[1] = 1;
820 category_bounds[2] = 1.065;
821 category_bounds[3] = 1.230;
822 category_bounds[4] = 1.500;
823 category_bounds[5] = 1.950;
824 category_bounds[6] = 2.800;
825 category_bounds[7] = 4.500;
826 category_bounds[8] = 6.200;
827 category_bounds[9] = 12.01;
828
829
830 /* initialize model coefficients */
831 a[1] = 96.63;
832 a[2] = 107.54;
833 a[3] = 98.73;
834 a[4] = 92.72;
835 a[5] = 86.73;
836 a[6] = 88.34;
837 a[7] = 78.63;
838 a[8] = 99.65;
839
840 b[1] = -0.47;
841 b[2] = 0.79;
842 b[3] = 0.70;
843 b[4] = 0.56;
844 b[5] = 0.98;
845 b[6] = 1.39;
846 b[7] = 1.47;
847 b[8] = 1.86;
848
849 c[1] = 11.50;
850 c[2] = 1.79;
851 c[3] = 4.40;
852 c[4] = 8.36;
853 c[5] = 7.10;
854 c[6] = 6.06;
855 c[7] = 4.93;
856 c[8] = -4.46;
857
858 d[1] = -9.16;
859 d[2] = -1.19;
860 d[3] = -6.95;
861 d[4] = -8.31;
862 d[5] = -10.94;
863 d[6] = -7.60;
864 d[7] = -11.37;
865 d[8] = -3.15;
866
867
868
869
870 for (i=1; i<=category_total_number; i++)
871 {
872 if ( (skyclearness >= category_bounds[i]) && (skyclearness < category_bounds[i+1]) )
873 category_number = i;
874 }
875
876 value = a[category_number] + b[category_number]*atm_preci_water +
877 c[category_number]*cos(sunzenith*M_PI/180) + d[category_number]*log(skybrightness);
878
879 return(value);
880 }
881
882
883 /* global horizontal diffuse efficacy model, according to PEREZ */
884 double glob_h_diffuse_effi_PEREZ()
885 {
886 double value;
887 double category_bounds[10], a[10], b[10], c[10], d[10];
888 int category_total_number, category_number, i;
889
890
891
892
893 check_parametrization();
894
895
896 /*if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
897 fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function glob_h_diffuse_PEREZ \n"); */
898
899
900
901 /* initialize category bounds (clearness index bounds) */
902
903 category_total_number = 8;
904
905 //XXX: category_bounds > 0.1
906 category_bounds[1] = 1;
907 category_bounds[2] = 1.065;
908 category_bounds[3] = 1.230;
909 category_bounds[4] = 1.500;
910 category_bounds[5] = 1.950;
911 category_bounds[6] = 2.800;
912 category_bounds[7] = 4.500;
913 category_bounds[8] = 6.200;
914 category_bounds[9] = 12.01;
915
916
917 /* initialize model coefficients */
918 a[1] = 97.24;
919 a[2] = 107.22;
920 a[3] = 104.97;
921 a[4] = 102.39;
922 a[5] = 100.71;
923 a[6] = 106.42;
924 a[7] = 141.88;
925 a[8] = 152.23;
926
927 b[1] = -0.46;
928 b[2] = 1.15;
929 b[3] = 2.96;
930 b[4] = 5.59;
931 b[5] = 5.94;
932 b[6] = 3.83;
933 b[7] = 1.90;
934 b[8] = 0.35;
935
936 c[1] = 12.00;
937 c[2] = 0.59;
938 c[3] = -5.53;
939 c[4] = -13.95;
940 c[5] = -22.75;
941 c[6] = -36.15;
942 c[7] = -53.24;
943 c[8] = -45.27;
944
945 d[1] = -8.91;
946 d[2] = -3.95;
947 d[3] = -8.77;
948 d[4] = -13.90;
949 d[5] = -23.74;
950 d[6] = -28.83;
951 d[7] = -14.03;
952 d[8] = -7.98;
953
954
955
956
957 category_number = -1;
958 for (i=1; i<=category_total_number; i++)
959 {
960 if ( (skyclearness >= category_bounds[i]) && (skyclearness < category_bounds[i+1]) )
961 category_number = i;
962 }
963
964 if (category_number == -1) {
965 if (suppress_warnings==0)
966 fprintf(stderr, "ERROR: Model parameters out of range, skyclearness = %lf \n", skyclearness);
967 print_error_sky();
968 exit(1);
969 }
970
971
972 value = a[category_number] + b[category_number]*atm_preci_water + c[category_number]*cos(sunzenith*M_PI/180) +
973 d[category_number]*log(skybrightness);
974
975 return(value);
976
977 }
978
979
980
981 /* direct normal efficacy model, according to PEREZ */
982
983 double direct_n_effi_PEREZ()
984
985 {
986 double value;
987 double category_bounds[10], a[10], b[10], c[10], d[10];
988 int category_total_number, category_number, i;
989
990
991 if ((skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup) && suppress_warnings==0)
992 fprintf(stderr, "Warning: skyclearness or skybrightness out of range in function direct_n_effi_PEREZ \n");
993
994
995 /* initialize category bounds (clearness index bounds) */
996
997 category_total_number = 8;
998
999 category_bounds[1] = 1;
1000 category_bounds[2] = 1.065;
1001 category_bounds[3] = 1.230;
1002 category_bounds[4] = 1.500;
1003 category_bounds[5] = 1.950;
1004 category_bounds[6] = 2.800;
1005 category_bounds[7] = 4.500;
1006 category_bounds[8] = 6.200;
1007 category_bounds[9] = 12.1;
1008
1009
1010 /* initialize model coefficients */
1011 a[1] = 57.20;
1012 a[2] = 98.99;
1013 a[3] = 109.83;
1014 a[4] = 110.34;
1015 a[5] = 106.36;
1016 a[6] = 107.19;
1017 a[7] = 105.75;
1018 a[8] = 101.18;
1019
1020 b[1] = -4.55;
1021 b[2] = -3.46;
1022 b[3] = -4.90;
1023 b[4] = -5.84;
1024 b[5] = -3.97;
1025 b[6] = -1.25;
1026 b[7] = 0.77;
1027 b[8] = 1.58;
1028
1029 c[1] = -2.98;
1030 c[2] = -1.21;
1031 c[3] = -1.71;
1032 c[4] = -1.99;
1033 c[5] = -1.75;
1034 c[6] = -1.51;
1035 c[7] = -1.26;
1036 c[8] = -1.10;
1037
1038 d[1] = 117.12;
1039 d[2] = 12.38;
1040 d[3] = -8.81;
1041 d[4] = -4.56;
1042 d[5] = -6.16;
1043 d[6] = -26.73;
1044 d[7] = -34.44;
1045 d[8] = -8.29;
1046
1047
1048
1049 for (i=1; i<=category_total_number; i++)
1050 {
1051 if ( (skyclearness >= category_bounds[i]) && (skyclearness < category_bounds[i+1]) )
1052 category_number = i;
1053 }
1054
1055 value = a[category_number] + b[category_number]*atm_preci_water + c[category_number]*exp(5.73*sunzenith*M_PI/180 - 5) + d[category_number]*skybrightness;
1056
1057 if (value < 0) value = 0;
1058
1059 return(value);
1060 }
1061
1062
1063 /*check the range of epsilon and delta indexes of the perez parametrization*/
1064 void check_parametrization()
1065 {
1066 if (skyclearness<skyclearinf || skyclearness>skyclearsup || skybrightness<skybriginf || skybrightness>skybrigsup)
1067 {
1068
1069 /* limit sky clearness or sky brightness, 2009 11 13 by J. Wienold */
1070 if (skyclearness<skyclearinf){
1071 if (suppress_warnings==0)
1072 /* fprintf(stderr,"Range warning: sky clearness too low (%lf)\n", skyclearness); */
1073 skyclearness=skyclearinf;
1074 }
1075 if (skyclearness>skyclearsup){
1076 if (suppress_warnings==0)
1077 /* fprintf(stderr,"Range warning: sky clearness too high (%lf)\n", skyclearness); */
1078 skyclearness=skyclearsup-0.1;
1079 }
1080 if (skybrightness<skybriginf){
1081 if (suppress_warnings==0)
1082 /* fprintf(stderr,"Range warning: sky brightness too low (%lf)\n", skybrightness); */
1083 skybrightness=skybriginf;
1084 }
1085 if (skybrightness>skybrigsup){
1086 if (suppress_warnings==0)
1087 /* fprintf(stderr,"Range warning: sky brightness too high (%lf)\n", skybrightness); */
1088 skybrightness=skybrigsup;
1089 }
1090
1091 return; }
1092 else return;
1093 }
1094
1095
1096 /* validity of the direct and diffuse components */
1097 void check_illuminances()
1098 {
1099 if (directilluminance < 0) {
1100 fprintf(stderr,"WARNING: direct illuminance < 0. Using 0.0\n");
1101 directilluminance = 0.0;
1102 }
1103 if (diffuseilluminance < 0) {
1104 fprintf(stderr,"WARNING: diffuse illuminance < 0. Using 0.0\n");
1105 diffuseilluminance = 0.0;
1106 }
1107 if (directilluminance > solar_constant_l*1000.0) {
1108 fprintf(stderr,"ERROR: direct illuminance exceeds solar constant\n");
1109 exit(1);
1110 }
1111 }
1112
1113
1114 void check_irradiances()
1115 {
1116 if (directirradiance < 0) {
1117 fprintf(stderr,"WARNING: direct irradiance < 0. Using 0.0\n");
1118 directirradiance = 0.0;
1119 }
1120 if (diffuseirradiance < 0) {
1121 fprintf(stderr,"WARNING: diffuse irradiance < 0. Using 0.0\n");
1122 diffuseirradiance = 0.0;
1123 }
1124 if (directirradiance > solar_constant_e) {
1125 fprintf(stderr,"ERROR: direct irradiance exceeds solar constant\n");
1126 exit(1);
1127 }
1128 }
1129
1130
1131
1132 /* Perez sky's brightness */
1133 double sky_brightness()
1134 {
1135 double value;
1136
1137 value = diffuseirradiance * air_mass() / ( solar_constant_e*get_eccentricity());
1138
1139 return(value);
1140 }
1141
1142
1143 /* Perez sky's clearness */
1144 double sky_clearness()
1145 {
1146 double value;
1147
1148 value = ( (diffuseirradiance + directirradiance)/(diffuseirradiance) + 1.041*sunzenith*M_PI/180*sunzenith*M_PI/180*sunzenith*M_PI/180 ) / (1 + 1.041*sunzenith*M_PI/180*sunzenith*M_PI/180*sunzenith*M_PI/180) ;
1149
1150 return(value);
1151 }
1152
1153
1154
1155 /* diffus horizontal irradiance from Perez sky's brightness */
1156 double diffuse_irradiance_from_sky_brightness()
1157 {
1158 double value;
1159
1160 value = skybrightness / air_mass() * ( solar_constant_e*get_eccentricity());
1161
1162 return(value);
1163 }
1164
1165
1166 /* direct normal irradiance from Perez sky's clearness */
1167 double direct_irradiance_from_sky_clearness()
1168 {
1169 double value;
1170
1171 value = diffuse_irradiance_from_sky_brightness();
1172 value = value * ( (skyclearness-1) * (1+1.041*sunzenith*M_PI/180*sunzenith*M_PI/180*sunzenith*M_PI/180) );
1173
1174 return(value);
1175 }
1176
1177
1178
1179
1180 void illu_to_irra_index()
1181 {
1182 double test1=0.1, test2=0.1, d_eff;
1183 int counter=0;
1184
1185 diffuseirradiance = diffuseilluminance*solar_constant_e/(solar_constant_l*1000);
1186 directirradiance = directilluminance*solar_constant_e/(solar_constant_l*1000);
1187 skyclearness = sky_clearness();
1188 skybrightness = sky_brightness();
1189 check_parametrization();
1190
1191
1192 while ( ((fabs(diffuseirradiance-test1)>10) || (fabs(directirradiance-test2)>10)
1193 || (!(skyclearness<skyclearinf || skyclearness>skyclearsup))
1194 || (!(skybrightness<skybriginf || skybrightness>skybrigsup)) )
1195 && !(counter==9) )
1196 {
1197
1198 test1=diffuseirradiance;
1199 test2=directirradiance;
1200 counter++;
1201
1202 diffuseirradiance = diffuseilluminance/glob_h_diffuse_effi_PEREZ();
1203 d_eff = direct_n_effi_PEREZ();
1204
1205
1206 if (d_eff < 0.1)
1207 directirradiance = 0;
1208 else
1209 directirradiance = directilluminance/d_eff;
1210
1211 skybrightness = sky_brightness();
1212 skyclearness = sky_clearness();
1213 check_parametrization();
1214
1215 /*fprintf(stderr,"skyclearness = %lf, skybrightness = %lf, directirradiance = %lf, diffuseirradiance = %lf\n",skyclearness, skybrightness, directirradiance, diffuseirradiance);*/
1216
1217 }
1218
1219
1220 return;
1221 }
1222
1223 static int get_numlin(float epsilon)
1224 {
1225 if (epsilon < 1.065)
1226 return 0;
1227 else if (epsilon < 1.230)
1228 return 1;
1229 else if (epsilon < 1.500)
1230 return 2;
1231 else if (epsilon < 1.950)
1232 return 3;
1233 else if (epsilon < 2.800)
1234 return 4;
1235 else if (epsilon < 4.500)
1236 return 5;
1237 else if (epsilon < 6.200)
1238 return 6;
1239 return 7;
1240 }
1241
1242 /* sky luminance perez model */
1243 double calc_rel_lum_perez(double dzeta,double gamma,double Z,double epsilon,double Delta,float coeff_perez[])
1244 {
1245
1246 float x[5][4];
1247 int i,j,num_lin;
1248 double c_perez[5];
1249
1250 if ( (epsilon < skyclearinf) || (epsilon >= skyclearsup) )
1251 {
1252 fprintf(stderr,"Epsilon out of range in function calc_rel_lum_perez!\n");
1253 exit(1);
1254 }
1255
1256 /* correction de modele de Perez solar energy ...*/
1257 if ( (epsilon > 1.065) && (epsilon < 2.8) )
1258 {
1259 if ( Delta < 0.2 ) Delta = 0.2;
1260 }
1261
1262
1263 num_lin = get_numlin(epsilon);
1264
1265 for (i=0;i<5;i++)
1266 for (j=0;j<4;j++)
1267 {
1268 x[i][j] = *(coeff_perez + 20*num_lin + 4*i +j);
1269 /* fprintf(stderr,"x %d %d vaut %f\n",i,j,x[i][j]); */
1270 }
1271
1272
1273 if (num_lin)
1274 {
1275 for (i=0;i<5;i++)
1276 c_perez[i] = x[i][0] + x[i][1]*Z + Delta * (x[i][2] + x[i][3]*Z);
1277 }
1278 else
1279 {
1280 c_perez[0] = x[0][0] + x[0][1]*Z + Delta * (x[0][2] + x[0][3]*Z);
1281 c_perez[1] = x[1][0] + x[1][1]*Z + Delta * (x[1][2] + x[1][3]*Z);
1282 c_perez[4] = x[4][0] + x[4][1]*Z + Delta * (x[4][2] + x[4][3]*Z);
1283 c_perez[2] = exp( pow(Delta*(x[2][0]+x[2][1]*Z),x[2][2])) - x[2][3];
1284 c_perez[3] = -exp( Delta*(x[3][0]+x[3][1]*Z) )+x[3][2]+Delta*x[3][3];
1285 }
1286
1287
1288 return (1 + c_perez[0]*exp(c_perez[1]/cos(dzeta)) ) *
1289 (1 + c_perez[2]*exp(c_perez[3]*gamma) +
1290 c_perez[4]*cos(gamma)*cos(gamma) );
1291 }
1292
1293
1294
1295 /* coefficients for the sky luminance perez model */
1296 void coeff_lum_perez(double Z, double epsilon, double Delta, float coeff_perez[])
1297 {
1298 float x[5][4];
1299 int i,j,num_lin;
1300
1301 if ( (epsilon < skyclearinf) || (epsilon >= skyclearsup) )
1302 {
1303 fprintf(stderr,"Epsilon out of range in function calc_rel_lum_perez !\n");
1304 exit(1);
1305 }
1306
1307 /* correction du modele de Perez solar energy ...*/
1308 if ( (epsilon > 1.065) && (epsilon < 2.8) )
1309 {
1310 if ( Delta < 0.2 ) Delta = 0.2;
1311 }
1312
1313
1314 num_lin = get_numlin(epsilon);
1315
1316 /*fprintf(stderr,"numlin %d\n", num_lin);*/
1317
1318 for (i=0;i<5;i++)
1319 for (j=0;j<4;j++)
1320 {
1321 x[i][j] = *(coeff_perez + 20*num_lin + 4*i +j);
1322 /* printf("x %d %d vaut %f\n",i,j,x[i][j]); */
1323 }
1324
1325
1326 if (num_lin)
1327 {
1328 for (i=0;i<5;i++)
1329 *(c_perez+i) = x[i][0] + x[i][1]*Z + Delta * (x[i][2] + x[i][3]*Z);
1330
1331 }
1332 else
1333 {
1334 *(c_perez+0) = x[0][0] + x[0][1]*Z + Delta * (x[0][2] + x[0][3]*Z);
1335 *(c_perez+1) = x[1][0] + x[1][1]*Z + Delta * (x[1][2] + x[1][3]*Z);
1336 *(c_perez+4) = x[4][0] + x[4][1]*Z + Delta * (x[4][2] + x[4][3]*Z);
1337 *(c_perez+2) = exp( pow(Delta*(x[2][0]+x[2][1]*Z),x[2][2])) - x[2][3];
1338 *(c_perez+3) = -exp( Delta*(x[3][0]+x[3][1]*Z) )+x[3][2]+Delta*x[3][3];
1339
1340
1341 }
1342
1343
1344 return;
1345 }
1346
1347
1348
1349 /* degrees into radians */
1350 double radians(double degres)
1351 {
1352 return degres*M_PI/180.0;
1353 }
1354
1355
1356 /* radian into degrees */
1357 double degres(double radians)
1358 {
1359 return radians/M_PI*180.0;
1360 }
1361
1362
1363 /* calculation of the angles dzeta and gamma */
1364 void theta_phi_to_dzeta_gamma(double theta,double phi,double *dzeta,double *gamma, double Z)
1365 {
1366 *dzeta = theta; /* dzeta = phi */
1367 if ( (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi)) > 1 && (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi) < 1.1 ) )
1368 *gamma = 0;
1369 else if ( (cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi)) > 1.1 )
1370 {
1371 printf("error in calculation of gamma (angle between point and sun");
1372 exit(3);
1373 }
1374 else
1375 *gamma = acos(cos(Z)*cos(theta)+sin(Z)*sin(theta)*cos(phi));
1376 }
1377
1378
1379
1380 double integ_lv(float *lv,float *theta)
1381 {
1382 int i;
1383 double buffer=0.0;
1384
1385 for (i=0;i<145;i++)
1386 {
1387 buffer += (*(lv+i))*cos(radians(*(theta+i)));
1388 }
1389
1390 return buffer*2*M_PI/144;
1391 }
1392
1393
1394
1395 /* enter day number(double), return E0 = square(R0/R): eccentricity correction factor */
1396
1397 double get_eccentricity()
1398 {
1399 double day_angle;
1400 double E0;
1401
1402 day_angle = 2*M_PI*(daynumber - 1)/365;
1403 E0 = 1.00011+0.034221*cos(day_angle)+0.00128*sin(day_angle)+
1404 0.000719*cos(2*day_angle)+0.000077*sin(2*day_angle);
1405
1406 return (E0);
1407 }
1408
1409
1410 /* enter sunzenith angle (degrees) return relative air mass (double) */
1411 double air_mass()
1412 {
1413 double m;
1414 if (sunzenith>90)
1415 {
1416 fprintf(stderr, "Solar zenith angle larger than 90 degrees in function air_mass()\n");
1417 exit(1);
1418 }
1419 m = 1/( cos(sunzenith*M_PI/180)+0.15*exp( log(93.885-sunzenith)*(-1.253) ) );
1420 return(m);
1421 }
1422
1423
1424