Troubleshooting OMP Error #15: How to Resolve Libiomp5.dylib Initialization Issues

OpenMP (OMP) is a well-known parallel programming model that is widely used for shared-memory multiprocessing in a variety of programming languages. However, when working with OpenMP, you might encounter an error like this:

OMP: Error #15: Initializing libiomp5.dylib, but found libiomp5.dylib already initialized.

This error can be frustrating, but don't worry! In this guide, we'll walk you through the steps to resolve the Libiomp5.dylib initialization issues.

Table of Contents

Understanding the Error

The error message "OMP: Error #15: Initializing libiomp5.dylib, but found libiomp5.dylib already initialized" occurs when there are multiple instances of the OpenMP runtime library in your environment. This can happen if you have installed packages that depend on different versions of the same library.

To resolve this issue, you need to identify the conflicting libraries, remove the unnecessary one, and re-install the required version.

Step-by-Step Solution

Step 1: Identify the Conflicting Libraries

First, you'll need to find out which libraries are conflicting. You can use the otool command to check the library dependencies of your binary file.

otool -L <your_binary_file>

This command will display a list of dependent libraries. Look for multiple instances of libiomp5.dylib or other OpenMP libraries (like libgomp or libomp) in the list.

Step 2: Uninstall the Conflicting Library

Once you've identified the conflicting library, you need to uninstall it. If the library was installed using a package manager like Homebrew, you can use the following command to uninstall the package:

brew uninstall <package_name>

Alternatively, if the library was installed manually, you can remove the library file from the /usr/local/lib directory:

rm /usr/local/lib/libiomp5.dylib

Step 3: Reinstall the Required Library

After uninstalling the conflicting library, you'll need to reinstall the required version of the library. If you're using Homebrew, you can run:

brew install <required_package_name>

Otherwise, you can manually download and install the required library from the official OpenMP website.

Step 4: Test Your Code

Finally, recompile and run your code to check if the error has been resolved. If the error persists, double-check the library dependencies and try reinstalling the required library again.


Q: What is OpenMP?

A: OpenMP is an API for multi-platform shared-memory parallel programming in C, C++, and Fortran. It provides a portable, scalable model for developers to build parallel applications.

Q: What is Libiomp5.dylib?

A: Libiomp5.dylib is the macOS dynamic library for Intel's OpenMP runtime implementation. It provides support for executing OpenMP directives in your code.

Q: Can I use OpenMP with languages other than C, C++, and Fortran?

A: While OpenMP was primarily designed for C, C++, and Fortran, there are some projects and libraries that provide OpenMP-like functionality for other languages, such as PyMP for Python.

Q: How can I check if my compiler supports OpenMP?

A: To check if your compiler supports OpenMP, you can run the following command:

<your_compiler> --version

Most modern compilers, such as GCC, Clang, and Intel's compilers, support OpenMP by default.

Q: Are there any alternatives to OpenMP for parallel programming?

A: Yes, there are several alternatives for parallel programming, including MPI (Message Passing Interface), Pthreads (POSIX Threads), and CUDA for GPU programming.

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