topic Re: Need help on handling complex numbers in SAS Programming

Need help on handling complex numbers

DatNinjaTurtle — Mon, 08 Oct 2018 19:28:34 GMT

 call symput('theta',arcos(Variable1));

I was trying to compute the arcos of Variable1, whose value is much greater than 1.

Obviously, any value gt 1 is not a valid input argument for the function arcos() . I wonder if there is any clever way to bypass the restriction?

While on the subject, can I assign complex value to a variable in SAS?

Re: Need help on handling complex numbers

ChrisNZ — Mon, 08 Oct 2018 20:59:24 GMT

What do you mean bypass? What do you want arcos(2) to be?

As for complex numbers, SAS/IML is used. Lots of material if you do a web search like sas complex number

Re: Need help on handling complex numbers

DatNinjaTurtle — Mon, 08 Oct 2018 21:08:12 GMT

I was hoping to get complex output. like arccos(2)=0.0000 + 1.3170i.

Re: Need help on handling complex numbers

ChrisNZ — Mon, 08 Oct 2018 21:16:30 GMT

I see. My maths are too old...

Maybe @Rick_SAS would be able to help?

Re: Need help on handling complex numbers

Rick_SAS — Mon, 08 Oct 2018 21:57:33 GMT

SAS does not have built-in support for complex-valued analysis. There are a few instances where complex number arise in statistics (mostly time series and eigenvalues) but most SAS functions take real arguments. If you want to use complex values, you might want to consider symbolic math software such as Mathematica.

You can, of course, do these computations in SAS by defining your own functions, but it will be a pain. You can define the trig, arc-trig, and hyperbolic trig functions for complex numbers, but they are complicated and multivalued. You have to choose Principal Values to get an actual function.