find a vector solution from two constraints

[neilxu]

Hi All,

I used SAS/OR proc optmodel before in order to find a solution. But that's for a single number.

Now I need to randomly pick 100 records from 1000 records. There is another constaint, the sum of these 100 records must be a ceterain number (K).

So the constaints are: sum of the total number of records is 100 and the sum of records is K.

Where can I start? I look up some of examples but I cannot find anything similar.

Thanks

[RobPratt · Accepted solution]

I think you want to declare a binary variable for each record and then declare your two constraints, like this:

set RECORDS;
num a {RECORDS};
read data indata into RECORDS=[record] a;
var X {RECORDS} binary;
con NumberRecords:
   sum {r in RECORDS} X[r] = 100;
con SumRecords:
   sum {r in RECORDS} a[r]*X[r] = k;