Built-in DatePlus and DateDifference are much slower than DaysPlus
- To: mathgroup at smc.vnet.net
- Subject: [mg87829] Built-in DatePlus and DateDifference are much slower than DaysPlus
- From: Luci Ellis <luci at verbeia.com>
- Date: Fri, 18 Apr 2008 02:39:39 -0400 (EDT)
Dear MathGroup,
I am not sure if this is a question or comment. I thought I should note the
following timing differences between the built-in DateDifference and
DatePlus functions, and the corresponding functions from the Calendar
package, DaysBetween and DaysPlus. Timings are from an original iMac G5.
Do[
DaysBetween[{2000, 3, 3}, {2002, 2, 2}];, {1000}]; // Timing
Out[49]= {1.08407, Null}
Do[
DateDifference[{2000, 3, 3}, {2002, 2, 2}];, {1000}]; // Timing
Out[50]= {5.39334, Null}
In[56]:= Table[DaysPlus[{2000, 1, 1}, i], {i, 1000}]; // Timing
Out[56]= {1.88357, Null}
In[57]:= Table[DatePlus[{2000, 1, 1}, i], {i, 1000}]; // Timing
Out[57]= {2.75215, Null}
I got a 100% speed-up by switching to the functions from the package. This
is a puzzle, because the commands from the Calendar package would seem more
general. If anyone has any insights on why this might be, that would be
interesting. Otherwise I'm just putting the information out there, in case
it is helpful to someone.
Best regards,
Luci