Hello. 

I am trying to setup a C++ project with CMake for the compilation. However, I am having some issues when linking the Cplex CPO. For linking the Cplex dependecies, I used the FindCPLEX.cmake.

The complete setup can be seen in the repository, where I try to compile the cpoptimizer/examples/src/cpp/alloc.cpp. Since I am not sure if I can share this file, I left an empty src/main.cpp in the repository, so if someone wants to reproduce the experiment, you will have to ctrl+c/ctrl+v the content from your cplex folder.

Below follows my CMakeLists.txt:

cmake_minimum_required(VERSION 3.23)
project(CplexCP)

##### SETs
set (Project_PATH "${PROJECT_SOURCE_DIR}")
set (CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/support/cmake)
set (CMAKE_BUILD_TYPE Release) 
set (CMAKE_CXX_STANDARD 20)
set (BUILD_SHARED_LIBS On)

##### Packages
find_package (CPLEX)

##### Include Dirs 

link_directories(${CPLEX_CP_LIBRARY})

include_directories(
    SYSTEM
    includes
    "${PROJECT_BINARY_DIR}"
    "${CPLEX_CONCERT_INCLUDE_DIR}"
    "${CPLEX_ILOCPLEX_INCLUDE_DIR}"
    "${CPLEX_CP_INCLUDE_DIR}"
    )


##### Compile options 

add_compile_options(-Wall
    #
    -DIL_STD
    -Wfatal-errors
    -pedantic
    -fopenmp
    -DDEBUG
    -fdiagnostics-color=always
    -lz
    -std=c++20
    # CPLEX
    -lconcert 
    -lilocplex 
    -lcplex 
    -lcplex-cp
    -lcplex-concert
    -lcplex-library
    #
    -lm 
    -lpthread 
    -ldl
    -Wno-sign-compare
    )

file(GLOB_RECURSE SOURCES "src/*.cpp")

add_executable(
    main 
    ${SOURCES} 
    )

target_link_libraries(
    main 
    ${CPLEX_CONCERT_LIBRARY}
    ${CPLEX_ILOCPLEX_LIBRARY}
    ${CPLEX_LIBRARY}
    ${CPLEX_CP_LIBRARY}
    ${CPLEX_CP_LIBRARY_DEBUG}
    pthread 
    m 
    dl
    )

The cmake command works just fine, but the make, results in the following. The complete log can be seen here.

/usr/bin/ld: /opt/ibm/ILOG/CPLEX_Studio2211/cpoptimizer/lib/x86-64_linux/static_pic/libcp.a(cpengine.o): in the function `IlcCPEngineI::IlcCPEngineI(IlcCPI*, IlcAllocator*, long, IlcCPOManagerI*)':
cpengine.cpp:(.text+0x8ae6): reference to `CPXEclocksync' not defined
...
/usr/bin/ld: /opt/ibm/ILOG/CPLEX_Studio2211/cpoptimizer/lib/x86-64_linux/static_pic/libcp.a(linoptcplex.o): in the function `IlcLinOptCplex::parameterConfiguration(long, double)':
linoptcplex.cpp:(.text+0x5ad1): reference to `CPXsetintparam' not defined
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/main.dir/build.make:102: main] Error 1
make[1]: *** [CMakeFiles/Makefile2:83: CMakeFiles/main.dir/all] Error 2
make: *** [Makefile:91: all] Error 2

What am I missing in my CMakeLists.txt?

Thanks and regards.

Nevermind. Just found the proper CMake setup: https://github.com/martinWANG2014/CplexCPlusPlusDemo/tree/master.

Hello Ross,

You can use :

mdl.minimize(sum([end_of(itv) for itv in intervals]))

or

mdl.minimize(sum(end_of(itv) for itv in intervals))

Best regards,

Ross,

You can add a value in case of absence as follow:

mdl.minimize(sum([end_of(itv, horizon) for itv in intervals]))

If the itv is absent,  the value returned by end_of(itv) is equal to horizon. Where horizon is an integer.

Regards,

Ross,

   Here is one possible way: mdl.solve(TimeLimit=60, LogPeriod='Quiet', Workers=1, ...).

Regards,

 I would like to define a transition matrix for Interval Variables
In some documentation I found a statement: "Transition times can be modeled using tuples with three elements. The first element is the interval variable type of one task, the second is the interval variable type of the other task and the third element of the tuple is the transition time from the first to the second. An integer interval variable type can be associated with each interval variable."
I have defined many interval variables in my model, but I cannot find out what an "interval variable type" is nor how to define it

Combining IBM's CP Optimizer with CMake for C++ projects streamlines optimization tasks within a robust build environment. Leveraging CMake's flexibility in managing complex build configurations, developers can seamlessly integrate CP Optimizer into their projects, ensuring efficient resource allocation, scheduling, and constraint satisfaction. This synergy empowers teams to tackle intricate optimization challenges while maintaining a structured, manageable codebase, enhancing productivity and solution quality.

Hello Ross,

Here is a link that should help you: https://www.ibm.com/docs/en/icos/22.1.1?topic=models-modeling-sequence-dependent-setup-times

Here is a link to an example: https://ibmdecisionoptimization.github.io/docplex-doc/cp/visu.setup_times.py.html

Regards,

An "interval variable type" in this context is essentially an integer label that categorizes different types of interval variables. This type is used to define a transition matrix, specifying transition times between different interval types.

How to Define Interval Variable Types

1. Assign an Integer Type to Each Interval Variable:
   You need to associate each interval variable with an integer type. This integer serves as an identifier for that interval in the transition matrix.

2. Define the Transition Matrix Using Tuples:
   The transition times are then modeled as tuples:
   (interval_type_1, interval_type_2, transition_time) Here, interval_type_1 and interval_type_2 are the integer types of the interval variables.

Example:

Let's assume you have three types of interval variables in a scheduling model:

• Task A (Type 1)

• Task B (Type 2)

• Task C (Type 3)

You can define transition times as:

python


CopyEdit


transition_times = [
    (1, 2, 5),  # 5 time units from Type 1 (Task A) to Type 2 (Task B)
    (2, 3, 10), # 10 time units from Type 2 (Task B) to Type 3 (Task C)
    (1, 3, 7)   # 7 time units from Type 1 (Task A) to Type 3 (Task C)
]

In your model, you should ensure that each interval variable has a corresponding type, and use this type to look up transition times in the matrix.

Would you like more details on how to integrate this with a specific solver (e.g., CPLEX, Google OR-Tools)? 🚀