SPA coding help

Dear all,

i am trying to implement modified version for SPA.
can some one tell me how to calculate day_of year .or else share algorithm

fraction of year=(2*pi/365)*(day_of year-1+((hour-12)/24));

SPA, right.

  • Simple power analysis
  • Special Protection Area
  • Self-Propelled Artillery
  • Saddle point approximation

Or maybe, (and I hope this is it):

  • Special pale ale

SPA means solar position algorithm.I wanted calculate day of year . Let me know how to calculte day of year

Is Google broken where you are?

You want to calculate "day of year", starting from what ? The month and the day ?

I can't think of any good reason why a solar position algorithm would even want "day of year"

michinyon:
You want to calculate "day of year", starting from what ? The month and the day ?

I can't think of any good reason why a solar position algorithm would even want "day of year"

Starting from month

Well I don’t know how you can calculate it, just from the month. From the day and the month, you would write something like this.

int daysPrior[] = { 0,31,59,90,120,151,181,212,243,273,304,334 };

int dayOfYear ( int day, int month )    //  day is 1..31,  month is 1..12
{
    if ( month < 1 || month > 12 ) return -1 ;
    if ( day < 1 || day > 31 ) return -1 ;    // you can do a more thorough check if you want to 

    return ( daysPrior[month-1] + day );
}

You would also need to fix this for a leap year. It is still not clear to me why a solar positioning algorithm
would even need this, unless it is implemented in an unnecessarily complicated way.

How to add leap_year changes to be made

int leapPrior={0,31,60,91,121,152,182,213,244,274,305,335};

the below code has been worked , but What it will do during leap year.Where leap year date as above

michinyon:
Well I don’t know how you can calculate it, just from the month. From the day and the month, you would write something like this.

int daysPrior[] = { 0,31,59,90,120,151,181,212,243,273,304,334 };

int dayOfYear ( int day, int month )    //  day is 1…31,  month is 1…12
{
    if ( month < 1 || month > 12 ) return -1 ;
    if ( day < 1 || day > 31 ) return -1 ;    // you can do a more thorough check if you want to

return ( daysPrior[month-1] + day );
}




You would also need to fix this for a leap year. It is still not clear to me why a solar positioning algorithm
would even need this, unless it is implemented in an unnecessarily complicated way.
static int MNTH_DAYS[12]={
  31,28,31,30,31,30,31,31,30,31,30,31};

int leapYrDetect(){

  if(local_year%4)
  {
    MNTH_DAYS[1]=28;
    return(0);
  }
  else
  {
    MNTH_DAYS[1]=29;
    return(1);
  }
}

int daysPrior[] = { 0,31,59,90,120,151,181,212,243,273,304,334 };
int leapPrior[]={0,31,60,91,121,152,182,213,244,274,305,335};

int calcDayOfYear ( int dd, int mnth )    //  day is 1..31,  month is 1..12
{
    int yr_day;
    if(leapYrDetect()==0)
    {
      Serial.println("year is not leap year ");
    if ( mnth < 1 || mnth > 12 ) return -1 ;
    if ( dd < 1 || dd> 31 ) return -1 ;   
    yr_day= daysPrior[mnth-1] + dd ;
    
    Serial.print("year of day is:");
    Serial.println(yr_day);
    return (yr_day);
    }
    if(leapYrDetect()==1)
    {
     Serial.println("leap year has detected ");
    if ( mnth < 1 || mnth > 12 ) return -1 ;
    if ( dd < 1 || dd> 31 ) return -1 ;   
    yr_day=leapPrior[mnth-1]+dd;
     Serial.print("year of day is:");
    Serial.println(yr_day);
    return (yr_day);
      
    }
    
    
    
}