lp_get(Handle,node_count,N) prints message

Cplex produces an error message when you try and get the number of nodes
after an lp_probe.
Any ideas why this is so?

Stefano

Here is a session log:

pioneer: eclipse
ECLiPSe Constraint Logic Programming System [kernel]
Copyright Imperial College London and ICL
Certain libraries copyright Parc Technologies Ltd
GMP library copyright Free Software Foundation
Version 5.3 #41, Sat Nov 24 13:49 2001
[eclipse 1]: [user].
  
:- lib(eplex).

 test :-
        normalise_cstrs([
                Y =< 0.89 * X + 1,
                Y >= 0.95 * X + 0.5
                ],Norm,[]),
        lp_setup(Norm,max(X),[integers([X,Y])],Handle),
        lp_probe(Handle,max(Y),Cost),
        lp_get(Handle,node_count,Nodes),
        printf("cost = %w nodes = %w%n",[Cost,Nodes]).
range.eco  loaded traceable 0 bytes in 0.03 seconds
linearize.eco loaded traceable 0 bytes in 0.05 seconds
hash.eco   loaded traceable 0 bytes in 0.01 seconds
var_name.eco loaded traceable 0 bytes in 0.03 seconds
loading CPLEX 71 ... done
ILOG CPLEX 7.100, licensed to "parctechnologies-london", options: e m b 
eplex.eco  loaded traceable 0 bytes in 0.27 seconds
           user       compiled traceable 640 bytes in 0.27 seconds

Yes (0.27s cpu)
[eclipse 2]: lp_set(result_channel, +(output)).

Yes (0.00s cpu)
[eclipse 3]: trace.
Debugger switched on - creep mode
[eclipse 4]: test.
  (1) 1 CALL  test   %> set print_depth: [5]? 2
  (1) 1 CALL  test   %> creep
  (2) 2 CALL  normalise_cstrs([...], Norm, [])   %> skip
  (2) 2 EXIT  normalise_cstrs([...], [...], [])   %> skip
  (135) 2 CALL  lp_setup([...], max(...), [...], Handle)   %> skip
  (135) 2 EXIT  lp_setup([...], max(...), [...], prob(...))   %> skip
  (328) 2 CALL  lp_probe(prob(...), max(...), Cost)   %> skip
Tried aggregator 1 time.
No MIP presolve or aggregator reductions.
Presolve time =    0.00 sec.
MIP emphasis: optimality
Root relaxation solution time =    0.00 sec.
Objective is integral.

        Nodes                                         Cuts/
   Node  Left     Objective  IInf  Best Integer     Best Node    ItCnt
Gap

      0     0        8.4167     2                      8.4167        2

                     8.0000     1               Fractcuts:  2        3
*                    1.0000     0        1.0000      Cuts:  3        6

Mixed integer rounding cuts applied:  2
  (328) 2 EXIT  lp_probe(prob(...), max(...), 1.0000000000000071)   %> skip
  (442) 2 CALL  lp_get(prob(...), node_count, Nodes)   %> skip
CPLEX Error  1217: No solution exists.
  (442) 2 EXIT  lp_get(prob(...), node_count, 0)   %> skip
S (444) 2 CALL  printf("cost = %w nodes = %w%n", [...])   %> skip
cost = 1.00000000000001 nodes = 0
S (444) 2 EXIT  printf("cost = %w nodes = %w%n", [...])   %> skip
  (1) 1 EXIT  test   %> skip

Yes (0.01s cpu)
[eclipse 5]: 

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