Why do I obtain different results from the DATENUM and DATEVEC function in MATLAB 7.0 (R14) than I did in MATLAB 6.5 (R13SP1)?

When I execute the following command:

d = datenum('15:00:00')

In MATLAB 7.0 (R14), this returns:

 d = 

   7.3195e+005

while in MATLAB 6.5.1 (R13SP1), it returned:

 d = 

   0.625

Answer 1

[MathWorks Support Team]

This has been verified as a bug within the DATENUM function within MATLAB 7.0 (R14) in the way it handles specifying the string in "HH-MM-YY" syntax.

When specifying only the time, the DATENUM or DATEVEC functions in MATLAB 7.0 (R14) assume the day to be the first day of the current year. In MATLAB 6.5.1, they assume the day to be the 0 year "0/0/0000".

Currently, to emulate the behavior of MATLAB 6.5.1 (R13SP1), prepend this syntax specifying the 0 day, using:

d = datenum('0/0/0 15:00:00')