warning messages in SAS PROC OPTMODEL when migrated to 9.4

[#1]

We are migrating from SAS 9.2 to 9.4

while executing the PROC OPTMODEL in 9.4 receiving the following warning message.

WARNING 852-782: Explicit bounds override the default bounds of binary variable 'art'.

But No warning message was populated in 9.2

We are using same input files, same sas code in both 9.2 & 9.4

Please suggest how to solve this WARNING MESSAGE.

Quick solution/reply will be highliy appreciated.

[#2]

Hi,

Do you have the possibility of adding code/data to the thread to help us help you investigate?

Thanks,

Michael

[#3]

Refer the attached txt file for the code that is generating this Warning message in 9.4

As I said; same code was used in 9.2 and NO Warning messages.

[#4]

Use the "little running man" icon to post SAS code. No need for attached files, unless the code is really long.

proc optmodel ;
/* output tables */
 ods output SolutionSummary=&libstage..solution_status ;
/* declare index set */
set<str> artikel;
/* declare variables */
 var art{artikel} >= 0 binary ;
/* objective function */
num composed_meas{artikel};
max f=sum{i in artikel}composed_meas[i]*art[i];
/* constraints */
str artikelgroep {artikel};
str subgroep {artikel};
num diepte{artikel};
num basis_bit {artikel};
num op_rack_bit {artikel};
num basic_bit {artikel};
num verplicht {artikel};
num verboden {artikel};
num _BONI_MIN_EVD {artikel};
num _NM_MIN_BONI {artikel};
num _NM_MIN_EVD {artikel};
%do j=1 %to &n_artgr.;
num artgroep_&j {artikel};
%end;
%do s=1 %to &n_link.;
 num link_&s. {artikel};
%end;
num min_diepte;
%do l=1 %to &x.;
 &&con&l.;
%end;
/* read parameters */
 read data &libstage..basis into artikel=[artikelnaam_nl] artikelgroep subgroep composed_meas diepte 
op_rack_bit verboden
basic_bit basis_bit verplicht
%do s=1 %to &n_link.;
 link_&s.
%end;
_BONI_MIN_EVD _NM_MIN_BONI _NM_MIN_EVD
%do j=1 %to &n_artgr;
artgroep_&j.
%end;
;
/* solve and print the optimal solution */
 solve with milp / printfreq=1 relobjgap=0 absobjgap=0 maxtime=100; /* print each iteration to log */
 create data &libstage..solution from [artikelnaam_nl] art;
quit;

There must be a macro definition wrapped around this code, as you use macro loops. I suggest you post the whole macro and how the macro is called, so testers can set the same parameters.

[#5]

You could try declaring the 'art' variable as such

var art{artikel} binary ;

i.e. ommit the >=0 part. That should remove the warning in 9.4

thanks,

Michael

[#6]

Thanks. It works.

Could you please share some info why there are no warning message in 9.2 (but in 9.4)?

Is anything changed in 9.4 for PROC OPTMODEL ?

This information is much needed for Upgrade project.
Because we are using the PROC OPTMODEL in two more scripts for different requirement.

Thanks,
Kiran.

[#7 · Accepted solution]

That warning message was introduced in SAS/OR 14.1 (SAS 9.4M3) to clarify the behavior in cases like the following:

   var x binary <= 2;

A call of the EXPAND statement confirms that the upper bound changes from 1 to 2:

SAS Output

Var x INTEGER >= 0 <= 2

In your case, the >= 0 is redundant, and Michael correctly identified that removing it avoids the warning message.

Yes, SAS/OR has had several releases since 9.2, and in each new release PROC OPTMODEL usually contains a few additional features and performance improvements.  In the SAS/OR documentation, you can check the "What's New in SAS/OR" tab for each release to see the major changes.

[#8]

Thank for the explanation  RobPratt.

Thanks to both of you (Michael  & RobPratt) for the quick updates.
Have A nice weekend.

Thanks,
Kiran.