Exponential code

[ursula]

Hi,

Anyone can help me of how to code the below equation into SAS:

another one is (1e-6), how to code it in SAS?

Thanks in advance.

[Reeza]

EXP function for the e

** is power operator so for 2^3 you can do 2**3

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@ursula wrote:

Hi,

Anyone can help me of how to code the below equation into SAS:

another one is (1e-6), how to code it in SAS?

Thanks in advance.

---

[ballardw]

The 1E-6 is easy in SAS: That is acceptable as a fixed value though there might sometimes be some issues related to storage precision. The FORMAT you use to display the value might be of interest.

data example;
   file print;
   x=1E-6;
   put 'Best5. format' x= best5.;
   put '9.7 format '   x= 9.7;
run;

Since you have the same long exponent in the numerator and denominator I would suggest calculating that as another variable and have much simpler code to type like

FAST = exp(thatvar)/ (1+Exp(thatvar));

[s_lassen]

The formula can be calculated in a single step, but as the same complex expression occurs twice, it is faster to calculate it in two steps:

FAST=exp(-1.65+1.07*log(LSM)+2.66E-8*CAP**3-63.3/AST);                                                                                
FAST=FAST/(1+FAST);                                                                                                                   

- by "faster" I mean both the amount of typing to be done, and the CPU time for the calculation.

[FreelanceReinh · Accepted solution]

Hi @ursula,

You can also use the LOGISTIC function to make the code shorter:

FAST=logistic(-1.65+...);