[avr-libc-commit] [2330] Edited solar_declination() for clarity

[Mike Rice]

Revision: 2330
          http://svn.sv.gnu.org/viewvc/?view=rev&root=avr-libc&revision=2330
Author:   swfltek
Date:     2013-04-02 21:46:13 +0000 (Tue, 02 Apr 2013)
Log Message:
-----------
Edited solar_declination() for clarity

Modified Paths:
--------------
    trunk/avr-libc/libc/time/solar_declination.c

Modified: trunk/avr-libc/libc/time/solar_declination.c
===================================================================
--- trunk/avr-libc/libc/time/solar_declination.c        2013-04-02 21:30:50 UTC 
(rev 2329)
+++ trunk/avr-libc/libc/time/solar_declination.c        2013-04-02 21:46:13 UTC 
(rev 2330)
@@ -29,7 +29,7 @@
 /* $Id$ */
 
 /*
-       Basic Solar declination calculation.
+    Basic Solar Declination calculation.
 */
 
 #include <time.h>
@@ -38,20 +38,20 @@
 double
 solar_declination(time_t * timer)
 {
-       unsigned long   i, y;
-       double          d;
+    unsigned long   p, Yt;
+    double          d;
 
-       /* what is our orbital position? */
-       y = 31556926;           /* one tropical year */
-       i = *timer % y;
+    /* Determine the mother ships orbital position, as seconds into a tropical 
year */
+    Yt = 31556926;
+    p = *timer % Yt;
 
-       /* convert position to radians */
-       d = i;
-       d /= y;
-       d *= 6.283185307179586;
+    /* convert to radians */
+    d = p;
+    d /= Yt;
+    d *= 2.0 * M_PI;
 
-       /* compute result */
-       d = 0.006918 - 0.409092627750149 * cos(d) + 0.070257 * sin(d);
+    /* compute result */
+    d = 0.006918 - 0.409092627750149 * cos(d) + 0.070257 * sin(d);
 
-       return d;
+    return d;
 }