Functions and CALL Routines |
Returns the log of 1 plus the argument.
- x
-
specifies a numeric variable, constant, or expression.
The LOG1PX function computes the log of 1 plus the argument.
The LOG1PX function is mathematically defined by the following equation, where -1
< x:
![[equation]](images/deqn116.gif)
When x is close to 0, LOG1PX(x)
can be more accurate than LOG(1+x)
.
The following example computes the log of 1 plus the value 0.5.
data _null_;
x=log1px(0.5);
put x=;
run;
SAS writes the following output to the Log:
x=0.4054651081
In the following example, the value of X is computed by using the LOG1PX
function. The value of Y is computed by using the LOG function.
data _null_;
x=log1px(1.e-5);
put x= hex16.;
y=log(1+1.e-5);
put y= hex16.;
run;
SAS writes the following output to the Log:
x=3EE4F8AEA9AE7317
y=3EE4F8AEA9AF0A25
Copyright © 2011 by SAS Institute Inc., Cary, NC, USA. All rights reserved.