Accelerating MATLAB Performance

160 Accelerating MATLAB

®

Performance

% Using the internal dtstr2dtvecmx (25x faster)

dateVecs = dtstr2dtvecmx(timestamps,'yyyy-MM-dd HH:mm:ss');

⇨ Elapsed time is 0.008838 seconds.

The datenum function uses another internal function that we can utilize in a certain sit-

uation. Specically, if our input uses a 6-element numeric date-vector format,* then using

datenummx will be more efcient:

411

dateVecs = clock;

for idx=1:1000, dateNums = datenum(dateVecs); end

⇨ Elapsed time is 0.015782 seconds.

for idx=1:1000, dateNums = datenummx(dateVecs); end

⇨ Elapsed time is 0.001152 seconds.

datenummx used to be a separate mex le whose source ...