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#ifndef lint
static const char RCSid[] = "$Id: gendaymtx.c,v 2.26 2017/04/28 16:07:34 greg Exp $";
#endif
/*
* gendaymtx.c
*
* Generate a daylight matrix based on Perez Sky Model.
*
* Most of this code is borrowed (see copyright below) from Ian Ashdown's
* excellent re-implementation of Jean-Jacques Delaunay's gendaylit.c
*
* Created by Greg Ward on 1/16/13.
*/
/*********************************************************************
*
* H32_gendaylit.CPP - Perez Sky Model Calculation
*
* Version: 1.00A
*
* History: 09/10/01 - Created.
* 11/10/08 - Modified for Unix compilation.
* 11/10/12 - Fixed conditional __max directive.
* 1/11/13 - Tweaks and optimizations (G.Ward)
*
* Compilers: Microsoft Visual C/C++ Professional V10.0
*
* Author: Ian Ashdown, P.Eng.
* byHeart Consultants Limited
* 620 Ballantree Road
* West Vancouver, B.C.
* Canada V7S 1W3
* e-mail: ian_ashdown@helios32.com
*
* References: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R.
* Stewart. 1990. ìModeling Daylight Availability and
* Irradiance Components from Direct and Global
* Irradiance,î Solar Energy 44(5):271-289.
*
* Perez, R., R. Seals, and J. Michalsky. 1993.
* ìAll-Weather Model for Sky Luminance Distribution -
* Preliminary Configuration and Validation,î Solar Energy
* 50(3):235-245.
*
* Perez, R., R. Seals, and J. Michalsky. 1993. "ERRATUM to
* All-Weather Model for Sky Luminance Distribution -
* Preliminary Configuration and Validation,î Solar Energy
* 51(5):423.
*
* NOTE: This program is a completely rewritten version of
* gendaylit.c written by Jean-Jacques Delaunay (1994).
*
* Copyright 2009-2012 byHeart Consultants Limited. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted for personal and commercial purposes
* provided that redistribution of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer:
*
* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL byHeart Consultants Limited OR
* ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*********************************************************************/
/* Zenith is along the Z-axis */
/* X-axis points east */
/* Y-axis points north */
/* azimuth is measured as degrees or radians east of North */
/* Include files */
#define _USE_MATH_DEFINES
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "rtmath.h"
#include "rtio.h"
#include "resolu.h"
#include "platform.h"
#include "color.h"
#include "resolu.h"
char *progname; /* Program name */
char errmsg[128]; /* Error message buffer */
const double DC_SolarConstantE = 1367.0; /* Solar constant W/m^2 */
const double DC_SolarConstantL = 127.5; /* Solar constant klux */
double altitude; /* Solar altitude (radians) */
double azimuth; /* Solar azimuth (radians) */
double apwc; /* Atmospheric precipitable water content */
double dew_point = 11.0; /* Surface dew point temperature (deg. C) */
double diff_illum; /* Diffuse illuminance */
double diff_irrad; /* Diffuse irradiance */
double dir_illum; /* Direct illuminance */
double dir_irrad; /* Direct irradiance */
int julian_date; /* Julian date */
double perez_param[5]; /* Perez sky model parameters */
double sky_brightness; /* Sky brightness */
double sky_clearness; /* Sky clearness */
double solar_rad; /* Solar radiance */
double sun_zenith; /* Sun zenith angle (radians) */
int input = 0; /* Input type */
int output = 0; /* Output type */
extern double dmax( double, double );
extern double CalcAirMass();
extern double CalcDiffuseIllumRatio( int );
extern double CalcDiffuseIrradiance();
extern double CalcDirectIllumRatio( int );
extern double CalcDirectIrradiance();
extern double CalcEccentricity();
extern double CalcPrecipWater( double );
extern double CalcRelHorzIllum( float *parr );
extern double CalcRelLuminance( double, double );
extern double CalcSkyBrightness();
extern double CalcSkyClearness();
extern int CalcSkyParamFromIllum();
extern int GetCategoryIndex();
extern void CalcPerezParam( double, double, double, int );
extern void CalcSkyPatchLumin( float *parr );
extern void ComputeSky( float *parr );
/* Degrees into radians */
#define DegToRad(deg) ((deg)*(PI/180.))
/* Radiuans into degrees */
#define RadToDeg(rad) ((rad)*(180./PI))
/* Perez sky model coefficients */
/* Reference: Perez, R., R. Seals, and J. Michalsky, 1993. "All- */
/* Weather Model for Sky Luminance Distribution - */
/* Preliminary Configuration and Validation," Solar */
/* Energy 50(3):235-245, Table 1. */
static const double PerezCoeff[8][20] =
{
/* Sky clearness (epsilon): 1.000 to 1.065 */
{ 1.3525, -0.2576, -0.2690, -1.4366, -0.7670,
0.0007, 1.2734, -0.1233, 2.8000, 0.6004,
1.2375, 1.0000, 1.8734, 0.6297, 0.9738,
0.2809, 0.0356, -0.1246, -0.5718, 0.9938 },
/* Sky clearness (epsilon): 1.065 to 1.230 */
{ -1.2219, -0.7730, 1.4148, 1.1016, -0.2054,
0.0367, -3.9128, 0.9156, 6.9750, 0.1774,
6.4477, -0.1239, -1.5798, -0.5081, -1.7812,
0.1080, 0.2624, 0.0672, -0.2190, -0.4285 },
/* Sky clearness (epsilon): 1.230 to 1.500 */
{ -1.1000, -0.2515, 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,
-2.6204, -0.0156, 0.1597, 0.4199, -0.5562 },
/* Sky clearness (epsilon): 1.500 to 1.950 */
{ -0.5484, -0.6654, -0.2672, 0.7117, 0.7234,
-0.6219, -5.6812, 2.6297, 33.3389, -18.3000,
-62.2500, 52.0781, -3.5000, 0.0016, 1.1477,
0.1062, 0.4659, -0.3296, -0.0876, -0.0329 },
/* Sky clearness (epsilon): 1.950 to 2.800 */
{ -0.6000, -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, 1.4062,
0.3988, 0.0032, 0.0766, -0.0656, -0.1294 },
/* Sky clearness (epsilon): 2.800 to 4.500 */
{ -1.0156, -0.3670, 1.0078, 1.4051, 0.2875,
-0.5328, -3.8500, 3.3750, 14.0000, -0.9999,
-7.1406, 7.5469, -3.4000, -0.1078, -1.0750,
1.5702, -0.0672, 0.4016, 0.3017, -0.4844 },
/* Sky clearness (epsilon): 4.500 to 6.200 */
{ -1.0000, 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,
0.2656, 1.0468, -0.3788, -2.4517, 1.4656 },
/* Sky clearness (epsilon): 6.200 to ... */
{ -1.0500, 0.0289, 0.4260, 0.3590, -0.3250,
0.1156, 0.7781, 0.0025, 31.0625, -14.5000,
-46.1148, 55.3750, -7.2312, 0.4050, 13.3500,
0.6234, 1.5000, -0.6426, 1.8564, 0.5636 }
};
/* Perez irradiance component model coefficients */
/* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
/* Stewart. 1990. ìModeling Daylight Availability and */
/* Irradiance Components from Direct and Global */
/* Irradiance,î Solar Energy 44(5):271-289. */
typedef struct
{
double lower; /* Lower bound */
double upper; /* Upper bound */
} CategoryBounds;
/* Perez sky clearness (epsilon) categories (Table 1) */
static const CategoryBounds SkyClearCat[8] =
{
{ 1.000, 1.065 }, /* Overcast */
{ 1.065, 1.230 },
{ 1.230, 1.500 },
{ 1.500, 1.950 },
{ 1.950, 2.800 },
{ 2.800, 4.500 },
{ 4.500, 6.200 },
{ 6.200, 12.01 } /* Clear */
};
/* Luminous efficacy model coefficients */
typedef struct
{
double a;
double b;
double c;
double d;
} ModelCoeff;
/* Diffuse luminous efficacy model coefficients (Table 4, Eqn. 7) */
static const ModelCoeff DiffuseLumEff[8] =
{
{ 97.24, -0.46, 12.00, -8.91 },
{ 107.22, 1.15, 0.59, -3.95 },
{ 104.97, 2.96, -5.53, -8.77 },
{ 102.39, 5.59, -13.95, -13.90 },
{ 100.71, 5.94, -22.75, -23.74 },
{ 106.42, 3.83, -36.15, -28.83 },
{ 141.88, 1.90, -53.24, -14.03 },
{ 152.23, 0.35, -45.27, -7.98 }
};
/* Direct luminous efficacy model coefficients (Table 4, Eqn. 8) */
static const ModelCoeff DirectLumEff[8] =
{
{ 57.20, -4.55, -2.98, 117.12 },
{ 98.99, -3.46, -1.21, 12.38 },
{ 109.83, -4.90, -1.71, -8.81 },
{ 110.34, -5.84, -1.99, -4.56 },
{ 106.36, -3.97, -1.75, -6.16 },
{ 107.19, -1.25, -1.51, -26.73 },
{ 105.75, 0.77, -1.26, -34.44 },
{ 101.18, 1.58, -1.10, -8.29 }
};
#ifndef NSUNPATCH
#define NSUNPATCH 4 /* max. # patches to spread sun into */
#endif
extern int jdate(int month, int day);
extern double stadj(int jd);
extern double sdec(int jd);
extern double salt(double sd, double st);
extern double sazi(double sd, double st);
/* sun calculation constants */
extern double s_latitude;
extern double s_longitude;
extern double s_meridian;
int nsuns = NSUNPATCH; /* number of sun patches to use */
double fixed_sun_sa = -1; /* fixed solid angle per sun? */
int verbose = 0; /* progress reports to stderr? */
int outfmt = 'a'; /* output format */
int rhsubdiv = 1; /* Reinhart sky subdivisions */
COLOR skycolor = {.96, 1.004, 1.118}; /* sky coloration */
COLOR suncolor = {1., 1., 1.}; /* sun color */
COLOR grefl = {.2, .2, .2}; /* ground reflectance */
int nskypatch; /* number of Reinhart patches */
float *rh_palt; /* sky patch altitudes (radians) */
float *rh_pazi; /* sky patch azimuths (radians) */
float *rh_dom; /* sky patch solid angle (sr) */
#define vector(v,alt,azi) ( (v)[1] = tcos(alt), \
(v)[0] = (v)[1]*tsin(azi), \
(v)[1] *= tcos(azi), \
(v)[2] = tsin(alt) )
#define rh_vector(v,i) vector(v,rh_palt[i],rh_pazi[i])
#define rh_cos(i) tsin(rh_palt[i])
extern int rh_init(void);
extern float * resize_dmatrix(float *mtx_data, int nsteps, int npatch);
extern void AddDirect(float *parr);
static const char *
getfmtname(int fmt)
{
switch (fmt) {
case 'a':
return("ascii");
case 'f':
return("float");
case 'd':
return("double");
}
return("unknown");
}
int
main(int argc, char *argv[])
{
char buf[256];
int doheader = 1; /* output header? */
double rotation = 0; /* site rotation (degrees) */
double elevation; /* site elevation (meters) */
int dir_is_horiz; /* direct is meas. on horizontal? */
float *mtx_data = NULL; /* our matrix data */
int ntsteps = 0; /* number of rows in matrix */
int step_alloc = 0;
int last_monthly = 0; /* month of last report */
int inconsistent = 0; /* inconsistent options set? */
int mo, da; /* month (1-12) and day (1-31) */
double hr; /* hour (local standard time) */
double dir, dif; /* direct and diffuse values */
int mtx_offset;
int i, j;
progname = argv[0];
/* get options */
for (i = 1; i < argc && argv[i][0] == '-'; i++)
switch (argv[i][1]) {
case 'g': /* ground reflectance */
grefl[0] = atof(argv[++i]);
grefl[1] = atof(argv[++i]);
grefl[2] = atof(argv[++i]);
break;
case 'v': /* verbose progress reports */
verbose++;
break;
case 'h': /* turn off header */
doheader = 0;
break;
case 'o': /* output format */
switch (argv[i][2]) {
case 'f':
case 'd':
case 'a':
outfmt = argv[i][2];
break;
default:
goto userr;
}
break;
case 'O': /* output type */
switch (argv[i][2]) {
case '0':
output = 0;
break;
case '1':
output = 1;
break;
default:
goto userr;
}
if (argv[i][3])
goto userr;
break;
case 'm': /* Reinhart subdivisions */
rhsubdiv = atoi(argv[++i]);
break;
case 'c': /* sky color */
inconsistent |= (skycolor[1] <= 1e-4);
skycolor[0] = atof(argv[++i]);
skycolor[1] = atof(argv[++i]);
skycolor[2] = atof(argv[++i]);
break;
case 'd': /* solar (direct) only */
skycolor[0] = skycolor[1] = skycolor[2] = 0;
if (suncolor[1] <= 1e-4) {
inconsistent = 1;
suncolor[0] = suncolor[1] = suncolor[2] = 1;
}
break;
case 's': /* sky only (no direct) */
suncolor[0] = suncolor[1] = suncolor[2] = 0;
if (skycolor[1] <= 1e-4) {
inconsistent = 1;
skycolor[0] = skycolor[1] = skycolor[2] = 1;
}
break;
case 'r': /* rotate distribution */
if (argv[i][2] && argv[i][2] != 'z')
goto userr;
rotation = atof(argv[++i]);
break;
case '5': /* 5-phase calculation */
nsuns = 1;
fixed_sun_sa = PI/360.*atof(argv[++i]);
if (fixed_sun_sa <= 0) {
fprintf(stderr, "%s: missing solar disk size argument for '-5' option\n",
argv[0]);
exit(1);
}
fixed_sun_sa *= fixed_sun_sa*PI;
break;
default:
goto userr;
}
if (i < argc-1)
goto userr;
if (inconsistent)
fprintf(stderr, "%s: WARNING: inconsistent -s, -d, -c options!\n",
progname);
if (i == argc-1 && freopen(argv[i], "r", stdin) == NULL) {
fprintf(stderr, "%s: cannot open '%s' for input\n",
progname, argv[i]);
exit(1);
}
if (verbose) {
if (i == argc-1)
fprintf(stderr, "%s: reading weather tape '%s'\n",
progname, argv[i]);
else
fprintf(stderr, "%s: reading weather tape from <stdin>\n",
progname);
}
/* read weather tape header */
if (scanf("place %[^\r\n] ", buf) != 1)
goto fmterr;
if (scanf("latitude %lf\n", &s_latitude) != 1)
goto fmterr;
if (scanf("longitude %lf\n", &s_longitude) != 1)
goto fmterr;
if (scanf("time_zone %lf\n", &s_meridian) != 1)
goto fmterr;
if (scanf("site_elevation %lf\n", &elevation) != 1)
goto fmterr;
if (scanf("weather_data_file_units %d\n", &input) != 1)
goto fmterr;
switch (input) { /* translate units */
case 1:
input = 1; /* radiometric quantities */
dir_is_horiz = 0; /* direct is perpendicular meas. */
break;
case 2:
input = 1; /* radiometric quantities */
dir_is_horiz = 1; /* solar measured horizontally */
break;
case 3:
input = 2; /* photometric quantities */
dir_is_horiz = 0; /* direct is perpendicular meas. */
break;
default:
goto fmterr;
}
rh_init(); /* initialize sky patches */
if (verbose) {
fprintf(stderr, "%s: location '%s'\n", progname, buf);
fprintf(stderr, "%s: (lat,long)=(%.1f,%.1f) degrees north, west\n",
progname, s_latitude, s_longitude);
fprintf(stderr, "%s: %d sky patches per time step\n",
progname, nskypatch);
if (rotation != 0)
fprintf(stderr, "%s: rotating output %.0f degrees\n",
progname, rotation);
}
/* convert quantities to radians */
s_latitude = DegToRad(s_latitude);
s_longitude = DegToRad(s_longitude);
s_meridian = DegToRad(s_meridian);
/* process each time step in tape */
while (scanf("%d %d %lf %lf %lf\n", &mo, &da, &hr, &dir, &dif) == 5) {
double sda, sta;
/* make space for next time step */
mtx_offset = 3*nskypatch*ntsteps++;
if (ntsteps > step_alloc) {
step_alloc += (step_alloc>>1) + ntsteps + 7;
mtx_data = resize_dmatrix(mtx_data, step_alloc, nskypatch);
}
if (dif <= 1e-4) {
memset(mtx_data+mtx_offset, 0, sizeof(float)*3*nskypatch);
continue;
}
if (verbose && mo != last_monthly)
fprintf(stderr, "%s: stepping through month %d...\n",
progname, last_monthly=mo);
/* compute solar position */
julian_date = jdate(mo, da);
sda = sdec(julian_date);
sta = stadj(julian_date);
altitude = salt(sda, hr+sta);
azimuth = sazi(sda, hr+sta) + PI - DegToRad(rotation);
/* convert measured values */
if (dir_is_horiz && altitude > 0.)
dir /= sin(altitude);
if (input == 1) {
dir_irrad = dir;
diff_irrad = dif;
} else /* input == 2 */ {
dir_illum = dir;
diff_illum = dif;
}
/* compute sky patch values */
ComputeSky(mtx_data+mtx_offset);
AddDirect(mtx_data+mtx_offset);
}
/* check for junk at end */
while ((i = fgetc(stdin)) != EOF)
if (!isspace(i)) {
fprintf(stderr, "%s: warning - unexpected data past EOT: ",
progname);
buf[0] = i; buf[1] = '\0';
fgets(buf+1, sizeof(buf)-1, stdin);
fputs(buf, stderr); fputc('\n', stderr);
break;
}
/* write out matrix */
if (outfmt != 'a')
SET_FILE_BINARY(stdout);
#ifdef getc_unlocked
flockfile(stdout);
#endif
if (verbose)
fprintf(stderr, "%s: writing %smatrix with %d time steps...\n",
progname, outfmt=='a' ? "" : "binary ", ntsteps);
if (doheader) {
newheader("RADIANCE", stdout);
printargs(argc, argv, stdout);
printf("LATLONG= %.8f %.8f\n", RadToDeg(s_latitude),
-RadToDeg(s_longitude));
printf("NROWS=%d\n", nskypatch);
printf("NCOLS=%d\n", ntsteps);
printf("NCOMP=3\n");
fputformat((char *)getfmtname(outfmt), stdout);
putchar('\n');
}
/* patches are rows (outer sort) */
for (i = 0; i < nskypatch; i++) {
mtx_offset = 3*i;
switch (outfmt) {
case 'a':
for (j = 0; j < ntsteps; j++) {
printf("%.3g %.3g %.3g\n", mtx_data[mtx_offset],
mtx_data[mtx_offset+1],
mtx_data[mtx_offset+2]);
mtx_offset += 3*nskypatch;
}
if (ntsteps > 1)
fputc('\n', stdout);
break;
case 'f':
for (j = 0; j < ntsteps; j++) {
putbinary(mtx_data+mtx_offset, sizeof(float), 3,
stdout);
mtx_offset += 3*nskypatch;
}
break;
case 'd':
for (j = 0; j < ntsteps; j++) {
double ment[3];
ment[0] = mtx_data[mtx_offset];
ment[1] = mtx_data[mtx_offset+1];
ment[2] = mtx_data[mtx_offset+2];
putbinary(ment, sizeof(double), 3, stdout);
mtx_offset += 3*nskypatch;
}
break;
}
if (ferror(stdout))
goto writerr;
}
if (fflush(stdout) == EOF)
goto writerr;
if (verbose)
fprintf(stderr, "%s: done.\n", progname);
exit(0);
userr:
fprintf(stderr, "Usage: %s [-v][-h][-d|-s][-r deg][-m N][-g r g b][-c r g b][-o{f|d}][-O{0|1}] [tape.wea]\n",
progname);
exit(1);
fmterr:
fprintf(stderr, "%s: input weather tape format error\n", progname);
exit(1);
writerr:
fprintf(stderr, "%s: write error on output\n", progname);
exit(1);
}
/* Return maximum of two doubles */
double dmax( double a, double b )
{ return (a > b) ? a : b; }
/* Compute sky patch radiance values (modified by GW) */
void
ComputeSky(float *parr)
{
int index; /* Category index */
double norm_diff_illum; /* Normalized diffuse illuimnance */
int i;
/* Calculate atmospheric precipitable water content */
apwc = CalcPrecipWater(dew_point);
/* Calculate sun zenith angle (don't let it dip below horizon) */
/* Also limit minimum angle to keep circumsolar off zenith */
if (altitude <= 0.0)
sun_zenith = DegToRad(90.0);
else if (altitude >= DegToRad(87.0))
sun_zenith = DegToRad(3.0);
else
sun_zenith = DegToRad(90.0) - altitude;
/* Compute the inputs for the calculation of the sky distribution */
if (input == 0) /* XXX never used */
{
/* Calculate irradiance */
diff_irrad = CalcDiffuseIrradiance();
dir_irrad = CalcDirectIrradiance();
/* Calculate illuminance */
index = GetCategoryIndex();
diff_illum = diff_irrad * CalcDiffuseIllumRatio(index);
dir_illum = dir_irrad * CalcDirectIllumRatio(index);
}
else if (input == 1)
{
sky_brightness = CalcSkyBrightness();
sky_clearness = CalcSkyClearness();
/* Limit sky clearness */
if (sky_clearness > 11.9)
sky_clearness = 11.9;
/* Limit sky brightness */
if (sky_brightness < 0.01)
sky_brightness = 0.01;
/* Calculate illuminance */
index = GetCategoryIndex();
diff_illum = diff_irrad * CalcDiffuseIllumRatio(index);
dir_illum = dir_irrad * CalcDirectIllumRatio(index);
}
else if (input == 2)
{
/* Calculate sky brightness and clearness from illuminance values */
index = CalcSkyParamFromIllum();
}
if (output == 1) { /* hack for solar radiance */
diff_illum = diff_irrad * WHTEFFICACY;
dir_illum = dir_irrad * WHTEFFICACY;
}
if (bright(skycolor) <= 1e-4) { /* 0 sky component? */
memset(parr, 0, sizeof(float)*3*nskypatch);
return;
}
/* Compute ground radiance (include solar contribution if any) */
parr[0] = diff_illum;
if (altitude > 0)
parr[0] += dir_illum * sin(altitude);
parr[2] = parr[1] = parr[0] *= (1./PI/WHTEFFICACY);
multcolor(parr, grefl);
/* Calculate Perez sky model parameters */
CalcPerezParam(sun_zenith, sky_clearness, sky_brightness, index);
/* Calculate sky patch luminance values */
CalcSkyPatchLumin(parr);
/* Calculate relative horizontal illuminance */
norm_diff_illum = CalcRelHorzIllum(parr);
/* Check for zero sky -- make uniform in that case */
if (norm_diff_illum <= FTINY) {
for (i = 1; i < nskypatch; i++)
setcolor(parr+3*i, 1., 1., 1.);
norm_diff_illum = PI;
}
/* Normalization coefficient */
norm_diff_illum = diff_illum / norm_diff_illum;
/* Apply to sky patches to get absolute radiance values */
for (i = 1; i < nskypatch; i++) {
scalecolor(parr+3*i, norm_diff_illum*(1./WHTEFFICACY));
multcolor(parr+3*i, skycolor);
}
}
/* Add in solar direct to nearest sky patches (GW) */
void
AddDirect(float *parr)
{
FVECT svec;
double near_dprod[NSUNPATCH];
int near_patch[NSUNPATCH];
double wta[NSUNPATCH], wtot;
int i, j, p;
if (dir_illum <= 1e-4 || bright(suncolor) <= 1e-4)
return;
/* identify nsuns closest patches */
if (nsuns > NSUNPATCH)
nsuns = NSUNPATCH;
else if (nsuns <= 0)
nsuns = 1;
for (i = nsuns; i--; )
near_dprod[i] = -1.;
vector(svec, altitude, azimuth);
for (p = 1; p < nskypatch; p++) {
FVECT pvec;
double dprod;
rh_vector(pvec, p);
dprod = DOT(pvec, svec);
for (i = 0; i < nsuns; i++)
if (dprod > near_dprod[i]) {
for (j = nsuns; --j > i; ) {
near_dprod[j] = near_dprod[j-1];
near_patch[j] = near_patch[j-1];
}
near_dprod[i] = dprod;
near_patch[i] = p;
break;
}
}
wtot = 0; /* weight by proximity */
for (i = nsuns; i--; )
wtot += wta[i] = 1./(1.002 - near_dprod[i]);
/* add to nearest patch radiances */
for (i = nsuns; i--; ) {
float *pdest = parr + 3*near_patch[i];
float val_add = wta[i] * dir_illum / (WHTEFFICACY * wtot);
val_add /= (fixed_sun_sa > 0) ? fixed_sun_sa
: rh_dom[near_patch[i]] ;
*pdest++ += val_add*suncolor[0];
*pdest++ += val_add*suncolor[1];
*pdest++ += val_add*suncolor[2];
}
}
/* Initialize Reinhart sky patch positions (GW) */
int
rh_init(void)
{
#define NROW 7
static const int tnaz[NROW] = {30, 30, 24, 24, 18, 12, 6};
const double alpha = (PI/2.)/(NROW*rhsubdiv + .5);
int p, i, j;
/* allocate patch angle arrays */
nskypatch = 0;
for (p = 0; p < NROW; p++)
nskypatch += tnaz[p];
nskypatch *= rhsubdiv*rhsubdiv;
nskypatch += 2;
rh_palt = (float *)malloc(sizeof(float)*nskypatch);
rh_pazi = (float *)malloc(sizeof(float)*nskypatch);
rh_dom = (float *)malloc(sizeof(float)*nskypatch);
if ((rh_palt == NULL) | (rh_pazi == NULL) | (rh_dom == NULL)) {
fprintf(stderr, "%s: out of memory in rh_init()\n", progname);
exit(1);
}
rh_palt[0] = -PI/2.; /* ground & zenith patches */
rh_pazi[0] = 0.;
rh_dom[0] = 2.*PI;
rh_palt[nskypatch-1] = PI/2.;
rh_pazi[nskypatch-1] = 0.;
rh_dom[nskypatch-1] = 2.*PI*(1. - cos(alpha*.5));
p = 1; /* "normal" patches */
for (i = 0; i < NROW*rhsubdiv; i++) {
const float ralt = alpha*(i + .5);
const int ninrow = tnaz[i/rhsubdiv]*rhsubdiv;
const float dom = 2.*PI*(sin(alpha*(i+1)) - sin(alpha*i)) /
(double)ninrow;
for (j = 0; j < ninrow; j++) {
rh_palt[p] = ralt;
rh_pazi[p] = 2.*PI * j / (double)ninrow;
rh_dom[p++] = dom;
}
}
return nskypatch;
#undef NROW
}
/* Resize daylight matrix (GW) */
float *
resize_dmatrix(float *mtx_data, int nsteps, int npatch)
{
if (mtx_data == NULL)
mtx_data = (float *)malloc(sizeof(float)*3*nsteps*npatch);
else
mtx_data = (float *)realloc(mtx_data,
sizeof(float)*3*nsteps*npatch);
if (mtx_data == NULL) {
fprintf(stderr, "%s: out of memory in resize_dmatrix(%d,%d)\n",
progname, nsteps, npatch);
exit(1);
}
return(mtx_data);
}
/* Determine category index */
int GetCategoryIndex()
{
int index; /* Loop index */
for (index = 0; index < 8; index++)
if ((sky_clearness >= SkyClearCat[index].lower) &&
(sky_clearness < SkyClearCat[index].upper))
break;
return index;
}
/* Calculate diffuse illuminance to diffuse irradiance ratio */
/* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
/* Stewart. 1990. ìModeling Daylight Availability and */
/* Irradiance Components from Direct and Global */
/* Irradiance,î Solar Energy 44(5):271-289, Eqn. 7. */
double CalcDiffuseIllumRatio( int index )
{
ModelCoeff const *pnle; /* Category coefficient pointer */
/* Get category coefficient pointer */
pnle = &(DiffuseLumEff[index]);
return pnle->a + pnle->b * apwc + pnle->c * cos(sun_zenith) +
pnle->d * log(sky_brightness);
}
/* Calculate direct illuminance to direct irradiance ratio */
/* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
/* Stewart. 1990. ìModeling Daylight Availability and */
/* Irradiance Components from Direct and Global */
/* Irradiance,î Solar Energy 44(5):271-289, Eqn. 8. */
double CalcDirectIllumRatio( int index )
{
ModelCoeff const *pnle; /* Category coefficient pointer */
/* Get category coefficient pointer */
pnle = &(DirectLumEff[index]);
/* Calculate direct illuminance from direct irradiance */
return dmax((pnle->a + pnle->b * apwc + pnle->c * exp(5.73 *
sun_zenith - 5.0) + pnle->d * sky_brightness),
0.0);
}
/* Calculate sky brightness */
/* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
/* Stewart. 1990. ìModeling Daylight Availability and */
/* Irradiance Components from Direct and Global */
/* Irradiance,î Solar Energy 44(5):271-289, Eqn. 2. */
double CalcSkyBrightness()
{
return diff_irrad * CalcAirMass() / (DC_SolarConstantE *
CalcEccentricity());
}
/* Calculate sky clearness */
/* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
/* Stewart. 1990. ìModeling Daylight Availability and */
/* Irradiance Components from Direct and Global */
/* Irradiance,î Solar Energy 44(5):271-289, Eqn. 1. */
double CalcSkyClearness()
{
double sz_cubed; /* Sun zenith angle cubed */
/* Calculate sun zenith angle cubed */
sz_cubed = sun_zenith*sun_zenith*sun_zenith;
return ((diff_irrad + dir_irrad) / diff_irrad + 1.041 *
sz_cubed) / (1.0 + 1.041 * sz_cubed);
}
/* Calculate diffuse horizontal irradiance from Perez sky brightness */
/* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
/* Stewart. 1990. ìModeling Daylight Availability and */
/* Irradiance Components from Direct and Global */
/* Irradiance,î Solar Energy 44(5):271-289, Eqn. 2 */
/* (inverse). */
double CalcDiffuseIrradiance()
{
return sky_brightness * DC_SolarConstantE * CalcEccentricity() /
CalcAirMass();
}
/* Calculate direct normal irradiance from Perez sky clearness */
/* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
/* Stewart. 1990. ìModeling Daylight Availability and */
/* Irradiance Components from Direct and Global */
/* Irradiance,î Solar Energy 44(5):271-289, Eqn. 1 */
/* (inverse). */
double CalcDirectIrradiance()
{
return CalcDiffuseIrradiance() * ((sky_clearness - 1.0) * (1 + 1.041
* sun_zenith*sun_zenith*sun_zenith));
}
/* Calculate sky brightness and clearness from illuminance values */
int CalcSkyParamFromIllum()
{
double test1 = 0.1;
double test2 = 0.1;
int counter = 0;
int index = 0; /* Category index */
/* Convert illuminance to irradiance */
diff_irrad = diff_illum * DC_SolarConstantE /
(DC_SolarConstantL * 1000.0);
dir_irrad = dir_illum * DC_SolarConstantE /
(DC_SolarConstantL * 1000.0);
/* Calculate sky brightness and clearness */
sky_brightness = CalcSkyBrightness();
sky_clearness = CalcSkyClearness();
/* Limit sky clearness */
if (sky_clearness > 12.0)
sky_clearness = 12.0;
/* Limit sky brightness */
if (sky_brightness < 0.01)
sky_brightness = 0.01;
while (((fabs(diff_irrad - test1) > 10.0) ||
(fabs(dir_irrad - test2) > 10.0)) && !(counter == 5))
{
test1 = diff_irrad;
test2 = dir_irrad;
counter++;
/* Convert illuminance to irradiance */
index = GetCategoryIndex();
diff_irrad = diff_illum / CalcDiffuseIllumRatio(index);
dir_irrad = CalcDirectIllumRatio(index);
if (dir_irrad > 0.1)
dir_irrad = dir_illum / dir_irrad;
/* Calculate sky brightness and clearness */
sky_brightness = CalcSkyBrightness();
sky_clearness = CalcSkyClearness();
/* Limit sky clearness */
if (sky_clearness > 12.0)
sky_clearness = 12.0;
/* Limit sky brightness */
if (sky_brightness < 0.01)
sky_brightness = 0.01;
}
return GetCategoryIndex();
}
/* Calculate relative luminance */
/* Reference: Perez, R., R. Seals, and J. Michalsky. 1993. */
/* ìAll-Weather Model for Sky Luminance Distribution - */
/* Preliminary Configuration and Validation,î Solar Energy */
/* 50(3):235-245, Eqn. 1. */
double CalcRelLuminance( double gamma, double zeta )
{
return (1.0 + perez_param[0] * exp(perez_param[1] / cos(zeta))) *
(1.0 + perez_param[2] * exp(perez_param[3] * gamma) +
perez_param[4] * cos(gamma) * cos(gamma));
}
/* Calculate Perez sky model parameters */
/* Reference: Perez, R., R. Seals, and J. Michalsky. 1993. */
/* ìAll-Weather Model for Sky Luminance Distribution - */
/* Preliminary Configuration and Validation,î Solar Energy */
/* 50(3):235-245, Eqns. 6 - 8. */
void CalcPerezParam( double sz, double epsilon, double delta,
int index )
{
double x[5][4]; /* Coefficents a, b, c, d, e */
int i, j; /* Loop indices */
/* Limit sky brightness */
if (epsilon > 1.065 && epsilon < 2.8)
{
if (delta < 0.2)
delta = 0.2;
}
/* Get Perez coefficients */
for (i = 0; i < 5; i++)
for (j = 0; j < 4; j++)
x[i][j] = PerezCoeff[index][4 * i + j];
if (index != 0)
{
/* Calculate parameter a, b, c, d and e (Eqn. 6) */
for (i = 0; i < 5; i++)
perez_param[i] = x[i][0] + x[i][1] * sz + delta * (x[i][2] +
x[i][3] * sz);
}
else
{
/* Parameters a, b and e (Eqn. 6) */
perez_param[0] = x[0][0] + x[0][1] * sz + delta * (x[0][2] +
x[0][3] * sz);
perez_param[1] = x[1][0] + x[1][1] * sz + delta * (x[1][2] +
x[1][3] * sz);
perez_param[4] = x[4][0] + x[4][1] * sz + delta * (x[4][2] +
x[4][3] * sz);
/* Parameter c (Eqn. 7) */
perez_param[2] = exp(pow(delta * (x[2][0] + x[2][1] * sz),
x[2][2])) - x[2][3];
/* Parameter d (Eqn. 8) */
perez_param[3] = -exp(delta * (x[3][0] + x[3][1] * sz)) +
x[3][2] + delta * x[3][3];
}
}
/* Calculate relative horizontal illuminance (modified by GW) */
/* Reference: Perez, R., R. Seals, and J. Michalsky. 1993. */
/* ìAll-Weather Model for Sky Luminance Distribution - */
/* Preliminary Configuration and Validation,î Solar Energy */
/* 50(3):235-245, Eqn. 3. */
double CalcRelHorzIllum( float *parr )
{
int i;
double rh_illum = 0.0; /* Relative horizontal illuminance */
for (i = 1; i < nskypatch; i++)
rh_illum += parr[3*i+1] * rh_cos(i) * rh_dom[i];
return rh_illum;
}
/* Calculate earth orbit eccentricity correction factor */
/* Reference: Sen, Z. 2008. Solar Energy Fundamental and Modeling */
/* Techniques. Springer, p. 72. */
double CalcEccentricity()
{
double day_angle; /* Day angle (radians) */
double E0; /* Eccentricity */
/* Calculate day angle */
day_angle = (julian_date - 1.0) * (2.0 * PI / 365.0);
/* Calculate eccentricity */
E0 = 1.00011 + 0.034221 * cos(day_angle) + 0.00128 * sin(day_angle)
+ 0.000719 * cos(2.0 * day_angle) + 0.000077 * sin(2.0 *
day_angle);
return E0;
}
/* Calculate atmospheric precipitable water content */
/* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
/* Stewart. 1990. ìModeling Daylight Availability and */
/* Irradiance Components from Direct and Global */
/* Irradiance,î Solar Energy 44(5):271-289, Eqn. 3. */
/* Note: The default surface dew point temperature is 11 deg. C */
/* (52 deg. F). Typical values are: */
/* Celsius Fahrenheit Human Perception */
/* > 24 > 75 Extremely uncomfortable */
/* 21 - 24 70 - 74 Very humid */
/* 18 - 21 65 - 69 Somewhat uncomfortable */
/* 16 - 18 60 - 64 OK for most people */
/* 13 - 16 55 - 59 Comfortable */
/* 10 - 12 50 - 54 Very comfortable */
/* < 10 < 49 A bit dry for some */
double CalcPrecipWater( double dpt )
{ return exp(0.07 * dpt - 0.075); }
/* Calculate relative air mass */
/* Reference: Kasten, F. 1966. "A New Table and Approximation Formula */
/* for the Relative Optical Air Mass," Arch. Meteorol. */
/* Geophys. Bioklimataol. Ser. B14, pp. 206-233. */
/* Note: More sophisticated relative air mass models are */
/* available, but they differ significantly only for */
/* sun zenith angles greater than 80 degrees. */
double CalcAirMass()
{
return (1.0 / (cos(sun_zenith) + 0.15 * pow(93.885 -
RadToDeg(sun_zenith), -1.253)));
}
/* Calculate Perez All-Weather sky patch luminances (modified by GW) */
/* NOTE: The sky patches centers are determined in accordance with the */
/* BRE-IDMP sky luminance measurement procedures. (See for example */
/* Mardaljevic, J. 2001. "The BRE-IDMP Dataset: A New Benchmark */
/* for the Validation of Illuminance Prediction Techniques," */
/* Lighting Research & Technology 33(2):117-136.) */
void CalcSkyPatchLumin( float *parr )
{
int i;
double aas; /* Sun-sky point azimuthal angle */
double sspa; /* Sun-sky point angle */
double zsa; /* Zenithal sun angle */
for (i = 1; i < nskypatch; i++)
{
/* Calculate sun-sky point azimuthal angle */
aas = fabs(rh_pazi[i] - azimuth);
/* Calculate zenithal sun angle */
zsa = PI * 0.5 - rh_palt[i];
/* Calculate sun-sky point angle (Equation 8-20) */
sspa = acos(cos(sun_zenith) * cos(zsa) + sin(sun_zenith) *
sin(zsa) * cos(aas));
/* Calculate patch luminance */
parr[3*i] = CalcRelLuminance(sspa, zsa);
if (parr[3*i] < 0) parr[3*i] = 0;
parr[3*i+2] = parr[3*i+1] = parr[3*i];
}
}