Matlab datenum generation

I'm using dtstr2dtnummx because that is faster, but I faced a problem, this function is generation a different datenum, or maybe my date format is not correct

date = {'2011-03-13 23:59:59.100'}

out1 =datenum(date)

out2=dtstr2dtnummx(date,'yyyy-mm-dd HH:MM:SS.SSS')

and the outputs are:

date =

'2011-03-13 23:59:59.100'

out1 =

      734575.999989583

out2 =

      736开发者_开发问答281.960423495

I don't know where is the error

UPDATE

I found an answer, with the following dateformat I get the same result

dtstr2dtnummx(date,'YYYY-MM-dd HH:mm:ss.SSS')

But I don't know why like this, because I followed this tutorial, but I get the wrong output, If anybody know the answer please share it.

datenum and dtstr2dtnummx use different format strings: datenum calls cnv2icudf to convert "date format tokens to ICU date format tokens" (see help cnv2icudf) which are usable with dtstr2dtnummx. Note this includes swapping upper- and lowercase for MM (interchanging month and minutes). In other words, you used the documentation for datenum to create a format string for dtstr2dtnummx, which is undocumented and private.

To get the correct format string to use, you can call

cnv2icudf('yyyy-mm-dd HH:MM:SS.FFF')

resulting in

ans =

yyyy-MM-dd HH:mm:ss.SSS

which is quite close to the solution you found yourself.

Lesson learned: there is a reason why dtstr2dtnummx is a private function - don't call it until you understand the wrapper datenum ;-).

BTW, out of curiosity: Did you really profile your code and found datenum to be a major culprit?