odow
commented
3 years ago Here's a better example without JuMP:
using Cbc
ptr = Cbc_newModel()
Cbc_setParameter(ptr, "solve", "dualSimplex")
Cbc_loadProblem(
ptr,
1,
0,
C_NULL,
C_NULL,
C_NULL,
[0.0],
[1.0],
[1.0],
C_NULL,
C_NULL,
)
Cbc_setInteger(ptr, 0)
julia> Cbc_solve(ptr)
Welcome to the CBC MILP Solver
Version: 2.10.5
Build Date: Apr 14 2021
command line - Cbc_C_Interface -solve dualSimplex -solve -quit (default strategy 1)
Continuous objective value is 0 - 0.00 seconds
Cgl0004I processed model has 0 rows, 0 columns (0 integer (0 of which binary)) and 0 elements
Cbc3007W No integer variables - nothing to do
Cuts at root node changed objective from 0 to -1.79769e+308
Probing was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Gomory was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Knapsack was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Clique was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
MixedIntegerRounding2 was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
FlowCover was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
TwoMirCuts was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
ZeroHalf was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Result - Optimal solution found
Objective value: 0.00000000
Enumerated nodes: 0
Total iterations: 0
Time (CPU seconds): 0.00
Time (Wallclock seconds): 0.00
Optimal - objective value 0
Optimal objective 0 - 0 iterations time 0.002
signal (11): Segmentation fault: 11
in expression starting at REPL[6]:1
unknown function (ip: 0x0)
Allocations: 5245964 (Pool: 5243004; Big: 2960); GC: 6I guess you just shouldn't set solve to dualSimplex if it is a MIP? This issue trying to first solve with dualSimplex, then re-solve.
Calling the executable works:
shell> cat test.lp
\Problem name: ClpDefaultName
Minimize
obj: x0
Subject To
Bounds
0.300000000 <= x0 <= 1
Integers
x0
End
julia> Cbc_jll.cbc() do exe
run(`$(exe) test.lp -solve dualSimplex -solve -quit`)
end
Welcome to the CBC MILP Solver
Version: 2.10.5
Build Date: Apr 14 2021
command line - /Users/oscar/.julia/artifacts/fcc0f90ee62113a97e8e82c1b20a46265667d88d/bin/cbc test.lp -solve dualSimplex -solve -quit (default strategy 1)
Continuous objective value is 0.3 - 0.00 seconds
Cgl0004I processed model has 0 rows, 0 columns (0 integer (0 of which binary)) and 0 elements
Cbc3007W No integer variables - nothing to do
Cuts at root node changed objective from 1 to -1.79769e+308
Probing was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Gomory was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Knapsack was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Clique was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
MixedIntegerRounding2 was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
FlowCover was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
TwoMirCuts was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
ZeroHalf was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Result - Optimal solution found
Objective value: 1.00000000
Enumerated nodes: 0
Total iterations: 0
Time (CPU seconds): 0.01
Time (Wallclock seconds): 0.00
Optimal - objective value 1
Optimal objective 1 - 0 iterations time 0.002
Continuous objective value is 1 - 0.00 seconds
Cgl0004I processed model has 0 rows, 0 columns (0 integer (0 of which binary)) and 0 elements
Cbc3007W No integer variables - nothing to do
Cbc3007W No integer variables - nothing to do
Cbc0006I The LP relaxation is infeasible or too expensive
Cbc0045I Solution of 1 already found by heuristic
Cuts at root node changed objective from 1.79769e+308 to -1.79769e+308
Probing was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Gomory was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Knapsack was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Clique was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
MixedIntegerRounding2 was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
FlowCover was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
TwoMirCuts was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
ZeroHalf was tried 0 times and created 0 cuts of which 0 were active after adding rounds of cuts (0.000 seconds)
Result - Optimal solution found
Objective value: 1.00000000
Enumerated nodes: 0
Total iterations: 0
Time (CPU seconds): 0.00
Time (Wallclock seconds): 0.00
Total time (CPU seconds): 0.01 (Wallclock seconds): 0.00
Process(`/Users/oscar/.julia/artifacts/fcc0f90ee62113a97e8e82c1b20a46265667d88d/bin/cbc test.lp -solve dualSimplex -solve -quit`, ProcessExited(0))
johnzigla
jjhforrest
tkralphs
I am running into a segmentation fault with CBC solver, if I specify a method (such as dual simplex, barrier) to use for a MILP or for a pure binary linear program. This is done by setting the parameter
solveasdualSimplex. The solver finds a solution but then crashes. If I run it without specifying the method then it works fine.I am using JuMP/Julia to use Cbc solver and version of CBC is 2.10.5. The code below reproduces the error. This issue is also posted on discourse: https://discourse.julialang.org/t/bug-in-jump/62129
Is this an issue with CBC or am I doing something incorrectly?
Error message after CBC reports optimal solution