Installation¶

Requirements¶

• GCC 14 or Clang 18 / C++23. MIP++ targets GCC 14 / C++23, though its original target — GCC 15 / C++26 — remains the recommended toolchain. A handful of standard-library features it relies on that some implementations lack (std::views::concat before C++26, std::views::cartesian_product in libc++) are provided by built-in fallbacks, so GCC 14 or Clang 18 in C++23 mode is enough to build it. Clang is tested against libstdc++.
• At least one solver installed on the machine that runs your program (see below). Nothing is needed at compile time.

MIP++ is header-only and has no library dependency: there is nothing to build, and your binary never links against a solver SDK. Solver libraries are opened at runtime through the platform loader (dlopen on Linux and macOS, LoadLibrary on Windows).

Getting the headers¶

git clone https://github.com/fhamonic/mippp && cd mippp
conan create . -u -b=missing -pr=<your_conan_profile>

add_subdirectory(dependencies/mippp)
target_link_libraries(<target> INTERFACE mippp)

git clone https://github.com/fhamonic/mippp && cd mippp
cmake -S . -B build -DCMAKE_INSTALL_PREFIX=<prefix>
cmake --install build

Making solver libraries discoverable¶

The first model of a backend constructed in a process locates and loads the solver's shared library (through the backend's <solver>_api object, see Choosing a solver). Resolution proceeds in this order — first match wins:

1. An explicit path given to <solver>_api::load: highs_lp model(highs_api::load("/path/to/libhighs.so")); loads exactly that file.

2. The MIPPP_<SOLVER>_LIBRARY environment variable, used verbatim as the full path of the library file. This is the way to pin an exact file when several versions are installed, or when only a version-suffixed soname exists:

   export MIPPP_HIGHS_LIBRARY="/path/to/HiGHS/build/lib/libhighs.so.1.10.0"
   

   Recognized keys: GUROBI, CPLEX, XPRESS, MOSEK, COPT, SCIP, HIGHS, SOPLEX, CLP, CBC, GLPK.

3. The dynamic loader's search directories — LD_LIBRARY_PATH and the system library directories on Linux (with /etc/ld.so.conf honored), DYLD_LIBRARY_PATH and the usual locations on macOS, PATH on Windows. The first directory holding any of the backend's library names wins, as it would for the loader; when a backend drives several releases (libgurobi130.so, libgurobi120.so, …) and a directory holds more than one, the newest is taken. The conventional decorated name (libhighs.so) is preferred; if only version-suffixed variants exist (libhighs.so.1.10.0), the lexicographically greatest filename — usually the highest version — is picked. The result of this search is remembered for the rest of the process.

Whichever way the library was found, the backend then checks the release it reports against the ranges it has been validated on (the compatibility table) and warns on stderr when it lies outside them; the library is used regardless, and MIPPP_NO_VERSION_WARNING silences the warning.

Solvers installed through the system package manager (e.g. apt install coinor-clp coinor-libclp-dev libglpk-dev) are found without any configuration. Commercial and source-built solvers usually live outside the system directories, so export their locations from your shell profile, adjusting the base paths to your installation:

# Gurobi
export GUROBI_HOME="/path/to/solvers/gurobi1201/linux64"
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$GUROBI_HOME/lib"

# HiGHS
export HIGHS_HOME="/path/to/solvers/HiGHS"
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$HIGHS_HOME/lib"

# CPLEX
export CPLEX_STUDIO_BINARIES="/path/to/solvers/cplex-community/cplex/bin/x86-64_linux"
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$CPLEX_STUDIO_BINARIES"

# FICO Xpress (also needs its license variable)
export XPRESS_HOME="/path/to/solvers/xpressmp"
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$XPRESS_HOME/lib"
export XPAUTH_PATH="$XPRESS_HOME/bin"

(The same pattern applies to COPT, MOSEK, and COIN-OR builds — see CONTRIBUTING.md for the full list.)

Only export the solvers you actually have. If a library cannot be located, the model constructor throws a std::runtime_error naming the files it tried, the platform's search variable, and MIPPP_<SOLVER>_LIBRARY with its current value, quoted.

Checking that everything works¶

Build and run any of the examples — the smallest is simple_lp, which uses HiGHS. Each example folder is a complete Conan + CMake project that can be copied as the starting point of your own. If you cloned the repository, the test suite can also be run with make CONAN_PROFILE=<your_profile>, and restricted to one or a few backends with make test highs CONAN_PROFILE=<your_profile> or make test "clp;cbc" CONAN_PROFILE=<your_profile>; backends whose runtime library is missing are skipped automatically.

Next¶

A first model — the two-variable LP, line by line.