Hi   I am going through the example on SAS's website to learn about Proc Optmodel (the link below). https://documentation.sas.com/?cdcId=pgmsascdc&cdcVersion=9.4_3.2&docsetId=casmopt&docsetTarget=casmopt_intro_sect013.htm&locale=en   code taken from SAS website: proc optmodel; /* declare sets and data indexed by sets */ set <string> Products; set <string> Processes; num Profit{Products}; num AvailableTime{Processes}; num RequiredTime{Products,Processes}; /* declare the variable */ var Amount{Products}; /* maximize objective function (profit) */ maximize TotalProfit = sum{p in Products} Profit[p]*Amount[p]; /* subject to constraints */ con Availability{r in Processes}: sum{p in Products} RequiredTime[p,r]*Amount[p] <= AvailableTime[r]; /* abstract algebraic model that captures the structure of the */ /* optimization problem has been defined without referring */ /* to a single data constant */ /* populate model by reading in the specific data instance */ read data Products into Products=[name] Profit; read data Processes into Processes=[name] AvailableTime=Available_time {p in Products} <RequiredTime[p,name]= col(p)>; /* solve LP using primal simplex solver */ solve with lp / solver = primal_spx; /* display solution */ print Amount; quit;   1- My first question is on the parameter RequiredTime that  is being defined by two sets (products and processes). num RequiredTime{Products,Processes}; Requiredtime is only available in processess data set and not in products, what is the logic for defining this parameter against two datasets one of which does not contain this attribute? 2- the next question is if anyone can help me understand the constraint which is  summarizing all 4 constraints as explained in the example in one line?   Thank you   ... View more

Hi   I was searching for a macro to split my data into smaller data sets and found the following program on stackoverflow.  The code works but I still have the following questions: 1- how SAS creates data want1 while in the program it says:  %IF &I. > 1 %THEN %DO; ELSE %END; 2- why there is no % before Else? 3- how SAS decides to start data want2 from 250001?   thank you Shideh   %MACRO SPLIT(DATASET); %LET DATASET_ID = %SYSFUNC(OPEN(&DATASET.)); %LET NOBS = %SYSFUNC(ATTRN(NLOBS,&DATASET_ID.)); %LET NB_DATASETS = %SYSEVALF(&NOBS. / 250000, CEIL); DATA %DO I=1 %TO &NB_DATASETS.; WANT&I. %END;; SET &dataset; %DO I=1 %TO &NB_DATASETS.; %IF &I. > 1 %THEN %DO; ELSE %END; IF _N_ LE 2.5E5 * &I. THEN OUTPUT WANT&I.; %END; RUN; %MEND SPLIT;   ... View more