/*-------------------<-- Start of Description -->--------------------\
| Generate random variate from a tabled probability distribution; |
| The functio utilize the SAS function rantbl; |
|-----------------------------------------|
|--------------------------------------------------------------------|
|-------------------------|
| Arguments Need: |
| seed - seed; Required, default is the current system time; |
| var - the variable to save the generated random variates; |
| p - the proportion variables; |
| Note: 1) if p is an array, it must be entered as "of p{*}"; |
| if p is just a bunch of proportions, it must be |
| entered as "of p1 - p9" for example; |
| 2) the above "of" can be omitted; |
| lower - the lower bound; |
| temp - the seed value saver; |
| temp - a variable for internal use only; |
|---------------------------|
|--------------------------------------------------------------------|
|---------------------------------|
| Example |
| data one; |
| array _p(3) (0.25, 0.5, 0.25); |
| %_rantbl_(seed=1, var=x, p=of _p{*}); |
| put x _rantbl0_; |
| do i=1 to 100000; |
| x=%_rantbl_(seed=_rantbl0_, p=of _p{*}); |
| output; |
| end; |
| run; |
| %print(one(obs=200)); |
| Usage: _rantbl_(seed=%sysfunc(datetime(), 15.), var=REQUIRED, p=, |
| lower=, temp=_rantbl0_); |
\----------------------------------*/
%macro _rantbl_(seed=%sysfunc(datetime(), 15.), var=, p=, lower=,
temp=_rantbl0_);
/*--------------------------------------------\
| Copy Right: Duo Zhou; |
| Created: 3-22-2002 6:30pm; |
| Purpose: Generate random variates from a |
| tabled probability distribution; |
\--------------------------------------------*/
%if (%quote(&seed) eq) or (%quote(&p) eq) %then %do;
%if (%quote(&seed) eq) %then %do;
%put ==> Error: This is not a valid seed!;
%if (%length(&var)) %then %do; &var=.; %end;
%else %do; .;%end;
%end;
%if (%quote(&p) eq) %then %do;
%put ==> Error: I need a valid proportion or proportion array!;
%if (%length(&var)) %then %do; &var=.; %end;
%else %do; .;%end;
%end;
%goto finish;
%end;
%else %do;
%if (%length(&var)) %then %do;
%if (not %sysfunc(rxmatch(%sysfunc(rxparse(.|$a|$A|$w)),&seed))) %then %do;
drop &temp;
retain &temp &seed;
%let seed=&temp;
%end;
%if (%length(&p) ge 2) %then %do;
%if (%quote(%substr(%left(%upcase(&p)),1,2))) ne %quote(OF) %then %do;
call rantbl(&seed, of &p, &var);
%end;
%else %do;
call rantbl(&seed, &p, &var);
%end;
%end;
%else %do;
call rantbl(&seed, &p, &var);
%end;
%if (%length(&lower)) %then &var=&var;
%end;
%else %do;
%if (%length(&p) ge 2) %then %do;
%if (%quote(%substr(%left(%upcase(&p)),1,2))) ne %quote(OF) %then %do;
rantbl(&seed, of &p);
%end;
%else %do;
rantbl(&seed, &p);
%end;
%end;
%else %do;
rantbl(&seed, &p);
%end;
%end;
%if (%length(&lower)) %then +&lower-1;
%end;
%finish:
%mend _rantbl_;