[FlopCpp] Returning to the shell (FlopC++ constraint)

[Tim Hultberg]

Hi Vishy,
  second thing first:

To get the constraint to compile you must use
(li>MP_index_exp(curLev(A,I)) instead of (li>curLev(A,I)  [and
similarly for the (lj>curLev(A,I)]

For the first thing, I am not sure. I would be helpfull if you could
provide the complete model (since when I am running with some dummy
objective I dont observe the problem).
You might try to cure it by using MP_index_exp explicitly, i.e. (
li>MP_index_exp(curLev(A,I)-1) ) ,etc.  whenever you are comparing an
index with some expression.

Hope this helps.

Cheers, Tim



>>> "Vishy Jeet" <vishv.jeet at gmail.com> 12/02/2007 18:22:10 >>>
Hi,

I have written a little piece of my program below, the constraint
CostITDevCon2 is causing a problem, I can compile my program without
any
errors/warnings, but when I run it,  the program hangs and I don't get
any
message to know what went wrong. When I remove this constraint from
the
overall program everything works just fine. I think something is
seriously
wrong with this constraints, don't know what. Any help on this much
appreciated.


#define bigM 10000
MP_set A(3), I(4), L(3);

MP_data curLev(A,I), itDevCost(A,I,L)

MP_constraint CostITDevCon2(A,I)

MP_index li, lj; //alias for set L

MP_variable U(A,I,L), DC(A,I);

DC.lowerLimit(A, I) = 0;

U.binary();

CostITDevCon2(A,I).such_that(curLev(A,I)>=1) =

DC(A,I) >=  sum(L(li).such_that(li>curLev(A,I)-1),
(1-sum(L(lj).such_that((lj>curLev(A,I)-1) &&

(lj<=li)), U(A,I,lj)))*itDevCost(A,I,li)) +
bigM*(sum(L.such_that(L>curLev(A,I)-1),
U(A,I,L))-1);

The other strange thing is this when I write the above constraint like
below, I can't even compile my program:

CostITDevCon2(A,I).such_that(curLev(A,I)>=1) =

DC(A,I) >=  sum(L(li).such_that(li>curLev(A,I)),
(1-sum(L(lj).such_that((lj>curLev(A,I)) &&

(lj<=li)), U(A,I,lj)))*itDevCost(A,I,li)) +
bigM*(sum(L.such_that(L>curLev(A,I)),
U(A,I,L))-1);

Here I just remove "-1" from all such_that blocks; everything else is
just
the same.

For some verification purpose, I rewrote the entire program in
GAMS/CPLEX
combo and it works just fine over there.
curLev(A,I) is the data that contains either 1, 2, or 3.

best regards,
--vishy

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