Re: [office-formula] YEARFRAC/Basis in more detail

[Andreas J Guelzow <aguelzow@math.concordia.ab.ca>]

On Fri, 2007-25-05 at 17:02 -0400, David A. Wheeler wrote:
> One of the three main comments we got back on the formula spec was
> that "Basis"/YEARFRAC wasn't defined in enough detail.  When the test
> cases get removed, it'll be much worse.  In this case, I believe we
> should take the Excel values as "canonical" unless shown it should NOT
> be otherwise... but I've found NO place that actually defines it.

This assumes that all versions of XL in fact yield the same results,
which is contradiction which such (unverified) statements as:

quote from http://www.pcreview.co.uk/forums/thread-1746401.php
---------------------------------------------------------------------
Using this formula: =YEARFRAC(DATE(2002, 2, 28),DATE(2002, 12, 31),0)

In Excel 97: 0.833333333

In Excel 2002: 0.836111111

A difference of about a day.
---------------------------------------------------------------------

Moreover I doubt that a listing of 50 to 200000 cases will make a good
definition. 

Perhaps we should use a reference book such as "Money Market and Bond
Calculations" by Stigum and Robinson. It seems that MathWorks does
things like that. See
http://www.mathworks.com/support/solutions/data/1-3MPMX0.html?product=FI&solution=1-3MPMX0

Andreas
-- 
"Liberty consists less in acting according to
one's own pleasure, than in not being subject 
to the will and pleasure of other people. It 
consists also in our not subjecting the wills 
of other people to our own."  Rousseau


Prof. Dr. Andreas J. Guelzow
Dept. of Mathematical & Computing Sciences
Concordia University College of Alberta