MATLAB date format

0
votes

I'm trying to convert date string to date number using dtstr2dtnummx (three time faster than datenum), but for this input

dtstr2dtnummx({'2010-12-12 12:21:13.101'},'yyyy-mm-dd HH:MM:SS.FFF')

and this input

dtstr2dtnummx({'2010-12-12 12:21:13.121'},'yyyy-mm-dd HH:MM:SS.FFF')

getting the same output. I used the following tutorial to build up the date format.

Ahh sorry, UPDATED

1
datetimematlab
Those look exactly the same to me. Am I missing something? - Jim Clay

1 Answers

4
votes

The corresponding format of 'FFF' in datenum is 'SSS' in dtstr2dtnummx, as can be seen in cnv2icudf.m line #126. The end result is:

>> d1 = dtstr2dtnummx({'2010-12-12 12:21:13.101'},'yyyy-MM-dd HH:mm:ss.SSS')
d1 =
      734484.514734965

>> d2 = dtstr2dtnummx({'2010-12-12 12:21:13.121'},'yyyy-MM-dd HH:mm:ss.SSS')
d2 =
      734484.514735197

>> % double check the results - difference should equal 0.02 secs:
>> secsPerDay = 24*60*60;
>> timeDiff = secsPerDay * (d2-d1)
timeDiff =
      0.019996

I have now posted an article about this on http://undocumentedmatlab.com/blog/datenum-performance/