\$Title Test EMP Disjunction - Minimize the makespan (EMPDISJ1,SEQ=429) \$ontext This model is a variant of Raman & Grossmann, Computers and Chemical Engineering 18, 7, p.563-578, 1994. Contributor: Jan-H. Jagla and Alex Meeraus, January 2009 \$offtext sets j jobs s stages lt(j,j) upper triangle alias (j,jj),(s,ss); parameters w(j,jj) maximum pairwise waiting time pt(j) total processing time; variables t completion time x(j) job starting time positive variable x; binary variable y; equations comp(j) job completion time seq(j,jj) job sequencing j beore jj ; comp(j).. t =g= x(j) + pt(j); seq(j,jj)\$(not sameas(j,jj)).. x(j) + w(j,jj) =l= x(jj); model m / all /; * data for example 1 - 3 jobs and 3 stages sets j jobs / A, B, C /, s stages / 1*3 / table p(j,s) processing time 1 2 3 A 5 3 B 3 2 C 2 4 scalar optval / 11 /; * complete data preparation parameter c(j,s) stage completion time; lt(j,jj) = ord(j) < ord(jj); c(j,s) = sum(ss\$(ord(ss)<=ord(s)), p(j,ss)); w(j,jj) = smax(s, c(j,s) - c(jj,s-1)); pt(j) = sum(s, p(j,s)); file emp / "%emp.info%" /; put emp '* problem %gams.i%'; loop(lt(j,jj), put / 'disjunction *' seq(j,jj) 'else' seq(jj,j)); putclose; option limcol=0,limrow=0,optcr=0; solve m using EMP minimizing t; abort\$(abs(m.objval-optval) > 1e-6) 'we did not get the correct solution'; *Same test again but using keyword disjunction only once put emp '* problem %gams.i%' / 'disjunction '; loop(lt(j,jj), put / ' *' seq(j,jj) 'else' seq(jj,j)); putclose; option limcol=0,limrow=0,optcr=0; solve m using EMP minimizing t; abort\$(abs(m.objval-optval) > 1e-6) 'we did not get the correct solution';