title: What is the precise definition of JDE's Julian Date format?
body: <p>I am writing code to convert from a Gregorian date to a JDE (<a href="http://en.wikipedia.org/wiki/J._D._Edwards" rel="noreferrer">J.D.Edwards</a>) Julian date.</p>
  
  <p><em>Note: a <strong>JDE</strong> Julian date is different from the normal usage of the term <a href="http://en.wikipedia.org/wiki/Julian_day" rel="noreferrer">Julian date</a>.</em></p>
  
  <p>As far as I can work out from Googling, the definition of a JDE Julian date is:</p>
  
  <pre><code>1000*(year-1900) + dayofyear
  </code></pre>
  
  <p>where year is the 4-digit year (e.g. 2009), and dayofyear is 1 for 1st January, and counts up all year to either 365 or 366 for 31st December (depending whether this is a leap year).</p>
  
  <p>My question is this: are years before 1900 supported?  If so, does the above formula still hold, or should it be this:</p>
  
  <pre><code>1000*(year-1900) - dayofyear
  </code></pre>
  
  <p>(note minus instead of plus.)</p>
  
  <p>or something else?</p>
  
  <p>Does anyone have a link to the official documentation for this date format?</p>