topic Mathematical calculations in SAS/IML Software and Matrix Computations

Mathematical calculations

ieva — Fri, 25 Nov 2011 11:39:57 GMT

Hi,

I am wondering how far SAS can be used for mathematical calculations. Is there some way to use SAS for such operations like:

a) 1/0 = infinity

0/0 =NaN (not a number)

b) Somehow solving formulas. For example like in MatLab finding differential:

diff(X^3)

ans=3X^2

Sometimes it seems that SAS is a super-tool with all included J Or maybe this is an area where SAS can’t be used?

Ieva

Mathematical calculations

Rick_SAS — Sat, 26 Nov 2011 22:57:27 GMT

a) SAS uses missing values to represent NaNs. In statistics, an observation can be a NaN if it is missing for a statistical reason (for example, a survey question was left unanswered) or for a mathematical reason (the log of a non-positive number). SAS supports 28 missing values: see http://analytics.ncsu.edu/sesug/2005/TU06_05.PDF for details.

Some people assign the .P missing value to mean "positive infinity" and .N to mean "negative infinity," but most don't. To me a NaN is a NaN.

b) MATLAB licenses (or bought?) the Maple symbolic algebra engine. No, SAS does not include symbolic integration or differentiation. Some SAS procedures support automatic differentiation in order to compute the gradients and Jacobians of objective functions, but that feature is not universal.

Mathematical calculations

Ksharp — Mon, 28 Nov 2011 02:45:02 GMT

Yes. SAS has already offer such function. About detail ,refer to documentation.

data have;
  input a b;
  div=divide(a,b);
  cards;
1 0
0 0
0 1
1 .
0 1
. 1
;
run;
proc print;run;

Ksharp

Mathematical calculations

ieva — Mon, 28 Nov 2011 07:04:30 GMT

Thank you Rick and Ksharp for the explanations!