How do I obtain the machine epsilon in SAS?

How do I obtain开发者_如何学编程 the machine epsilon in SAS?

I just googled it: http://www.google.com/search?q=How+do+I+obtain+the+machine+epsilon+in+SAS

First hit:

Use CONSTANT('MACEPS').

This answer is sort of true.

However for doing calculations in the data step it is most likely 1*10^-12 because certain functions in SAS (eg log) round to this precision as part of their spec. I am not sure about IML but I think that uses datastep functions. That could give a different result.