Installing OR-Tools .Net from Source on MacOS

Introduction

This guide explains how to install OR-Tools from source, with support for .Net, on MacOS. Unless you plan to modify the source code or use a third-party solver with OR-Tools, we recommend the binary installation.

Although these instructions might also work on other MacOS variants, we have only tested them on machines meeting the following requirements:

• MacOS 11.6 (Big Sur) 64-bit (x86_64)

Note: OR-Tools only supports the x86-64 (also known as amd64) architecture.

Prerequisites

The following sections describe the prerequisites for installing OR-Tools from source.

Xcode Command Line Tools

You must install the Xcode Command Line Tools. To do so, open the Terminal, found in /Applications/Utilities/, and enter:

xcode-select --install

Click “Install” to download and install Xcode Command Line Tools. You don’t need to "Get Xcode" from the App Store. If you have a slow Internet connection, it may take many minutes.

Verify that you’ve successfully installed Xcode Command Line Tools:

xcode-select -p

You should see:

/Applications/Xcode.app/Contents/Developer

Homebrew

To install the remaining prerequisites, we recommend first installing the "missing package manager for macOS" otherwise known as Homebrew. To do so, open a terminal window and enter:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew update

To verify that you’ve successfully installed brew:

brew --version

You should see:

Homebrew 1.6.9-8-g25542d7
Homebrew/homebrew-core (git revision 0e0c84; last commit 2018-06-20)

C++ tools

To install C++ tools, open a terminal window and enter:

brew install cmake wget pkg-config

SWIG tool

To install SWIG tool, open a terminal window and enter:

brew install swig

.Net tools

To install .Net tools, open a terminal window and enter:

brew cask install dotnet-sdk

Download the source code

There are two distinct branches of the OR-Tools source code on GitHub: stable and master. The stable branch has been thoroughly tested and should work flawlessly on all supported platforms. The master branch is where the latest updates and improvements have been applied; it's more current, but less stable.

Download the stable source code

You can get the stable source code for OR-Tools in either of the following ways:

• Clone the stable branch by entering

  git clone https://github.com/google/or-tools

• Download the latest release in a compressed file, by clicking the Clone or download button in GitHub.

Warning: The full path to the installation directory (where you extract the files) must not contain any spaces.

Download the master source code

To retrieve the source code from the master branch, enter

git clone -b master https://github.com/google/or-tools

Download previous releases

You can get the source code for previous releases in either of the following ways:

• Download a previous release from the GitHub release page.
• Assuming you have already created a local repository (by git clone), you can check out a specific release using a Git tag. For example, to work with the v9.1 release instead of the master branch, enter the following commands in your local repo:

  git fetch --all --tags --prune

  git checkout tags/v7.5 -b v7.5

Build third parties

Before building OR-Tools, you'll need to build the required third party software.

Open a terminal and navigate to the directory where you extracted the files. Then enter:

make third_party

Using SCIP

Since v7.8, SCIP is now integrated so you won't have to install it manually.

Warning:While OR-Tools ships with SCIP, please consult the SCIP license to ensure that you are complying with it.

Using Gurobi

Gurobi is now pre-integrated. When needed, at runtime, OR-Tools will search for the Gurobi shared library in the default install path of the Gurobi installers on MAC OS X and Windows, or by using the GUROBI_HOME environment variable.

Using an optional third-party MIP solver

You can also use OR-Tools with any of the following optional third-party MIP solvers whose support is disabled by default:

• CPLEX
• GLPK (Linux and MacOS only)
• Xpress Solver

To configure OR-Tools to use one of these solvers, do the following steps:

1. Install the optional solver following the vendor instruction.
2. Open Makefile.local and add the path to the directory where you have installed the solver. For example, for CPLEX you would add this:

   UNIX_CPLEX_DIR=cplex/install/dir

Build the source code

To build the source code, open a terminal and navigate to the directory where you extracted the files. Then enter the following command to compile OR-Tools:

make dotnet

Test the source code

You can check that everything is running correctly by entering:

make test_dotnet

This runs a selection of examples for OR-Tools. If all the examples run successfully, you are ready to get started with OR-Tools.

Cleaning the build files

If you need to re-install OR-Tools, the command:

make clean_third_party

will remove all compiled dependencies and Makefile.local. This can be useful for resetting to a clean state.

Then re-enter the commands

make third_party

make dotnet