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@mikofski mikofski/solpos_mex.c
Last active Jun 7, 2018

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MATLAB mex gateway function for NREL SOLPOS
/*==========================================================
* solpos.c - NREL solar position calculator
*
* calculates solar position from location and time
*
* The calling syntax is:
*
* angles = solpos(location,datetime,weather)
*
* This is a MEX-file for MATLAB.
*========================================================*/
#include "mex.h"
/* ===============================================================
* INSERT THE NREL SOLPOS.C SOURCE CODE HERE
* http://rredc.nrel.gov/solar/codesandalgorithms/solpos/solpos.c
*
* ALSO DOWNLOAD HEADER TO SAME FOLDER BEFORE COMPILING IN MATLAB
* http://rredc.nrel.gov/solar/codesandalgorithms/solpos/solpos00.h
*
* BASED ON STEST00 FROM NREL
* http://rredc.nrel.gov/solar/codesandalgorithms/solpos/stest00.c
*
* FOR MORE INFO SEE MAIN NREL WEBSITE
* http://rredc.nrel.gov/solar/codesandalgorithms/solpos/
* =============================================================== */
/* The gateway function */
void mexFunction( int nlhs, mxArray *plhs[],
int nrhs, const mxArray *prhs[])
{
/* variable declarations here */
struct posdata pd, *pdat; /* declare a posdata struct and a pointer for
* it (if desired, the structure could be
* allocated dynamically with malloc) */
long retval; /* to capture S_solpos return codes */
/* variable declarations here */
/* inputs */
double *location; /* latitude, longitude, UTC timezone */
double *datetime; /* year, month, day, hour, minute, seconds */
double *weather; /* pressure, temperature */
/* outputs */
double *angles; /* zenith, azimuth */
/* check for proper number of arguments */
if(nrhs!=3) {
mexErrMsgIdAndTxt("DBM:solpos:nrhs","Three inputs required.");
}
if(nlhs!=1) {
mexErrMsgIdAndTxt("DBM:solpos:nlhs","One output required.");
}
/* check that number of rows & columns in input arguments */
if(mxGetM(prhs[0])!=1) {
mexErrMsgIdAndTxt("DBM:solpos:notRowVector","Location should be row vector.");
}
if(mxGetN(prhs[0])!=3) {
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput","Location should be 3 column row vector with latitude, longitude, timezone.");
}
if(mxGetM(prhs[1])!=1) {
mexErrMsgIdAndTxt("DBM:solpos:notRowVector","Datetime should be row vector.");
}
if(mxGetN(prhs[1])!=6) {
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput","Datetime should be 6 column row vector with year, month, day, hour, minute, second.");
}
if(mxGetM(prhs[2])!=1) {
mexErrMsgIdAndTxt("DBM:solpos:notRowVector","Weather should be row vector.");
}
if(mxGetN(prhs[2])!=2) {
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput","Weather should be 6 column row vector with pressure and temperature.");
}
/* get pointer to the real data in the input matrix */
location = mxGetPr(prhs[0]);
datetime = mxGetPr(prhs[1]);
weather = mxGetPr(prhs[2]);
/* create the output matrix */
plhs[0] = mxCreateDoubleMatrix(1, 2, mxREAL);
/* get a pointer to the real data in the output matrix */
angles = mxGetPr(plhs[0]);
/* code here */
/************** Begin demo program **************/
pdat = &pd; /* point to the structure for convenience */
/* Initialize structure to default values. (Optional only if ALL input
* parameters are initialized in the calling code, which they are not
* in this example.) */
S_init(pdat);
pdat->function = ( (S_SOLAZM | S_REFRAC) & ~S_DOY );
pdat->timezone = location[2]; // -8; //UTC
pdat->longitude = location[1]; //-119.2022; //degrees
pdat->latitude = location[0]; //35.56836; //degrees
pdat->press = weather[0]; //1015.62055; //mbar
pdat->temp = weather[1]; //40.0; //deg C
pdat->tilt = 0;
pdat->aspect = 180;
pdat->year = datetime[0];
//using ~S_DOY so it will calculate the day of year for me
pdat->month = datetime[1];
pdat->day = datetime[2];
pdat->hour = datetime[3];
pdat->minute = datetime[4];
pdat->second = datetime[5];
/* call the computational routine */
retval = S_solpos(pdat); /* S_solpos function call */
//S_decode(retval, pdat); /* ALWAYS look at the return code! */
/*============================================================================
* decodes the error codes from S_solpos return value
*----------------------------------------------------------------------------*/
if ( retval & (1L << S_YEAR_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the year: %d [1950-2050]\n",
pdat->year);
if ( retval & (1L << S_MONTH_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the month: %d\n",
pdat->month);
if ( retval & (1L << S_DAY_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the day-of-month: %d\n",
pdat->day);
if ( retval & (1L << S_DOY_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the day-of-year: %d\n",
pdat->daynum);
if ( retval & (1L << S_HOUR_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the hour: %d\n",
pdat->hour);
if ( retval & (1L << S_MINUTE_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the minute: %d\n",
pdat->minute);
if ( retval & (1L << S_SECOND_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the second: %d\n",
pdat->second);
if ( retval & (1L << S_TZONE_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the time zone: %f\n",
pdat->timezone);
if ( retval & (1L << S_INTRVL_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the interval: %d\n",
pdat->interval);
if ( retval & (1L << S_LAT_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the latitude: %f\n",
pdat->latitude);
if ( retval & (1L << S_LON_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the longitude: %f\n",
pdat->longitude);
if ( retval & (1L << S_TEMP_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the temperature: %f\n",
pdat->temp);
if ( retval & (1L << S_PRESS_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the pressure: %f\n",
pdat->press);
if ( retval & (1L << S_TILT_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the tilt: %f\n",
pdat->tilt);
if ( retval & (1L << S_ASPECT_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the aspect: %f\n",
pdat->aspect);
if ( retval & (1L << S_SBWID_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the shadowband width: %f\n",
pdat->sbwid);
if ( retval & (1L << S_SBRAD_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the shadowband radius: %f\n",
pdat->sbrad);
if ( retval & (1L << S_SBSKY_ERROR) )
mexErrMsgIdAndTxt("DBM:solpos:incorrectInput", "S_decode ==> Please fix the shadowband sky factor: %f\n",
pdat->sbsky);
/* output off MEX function */
angles[0] = pdat->zenref;
angles[1] = pdat->azim;
}
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